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Sample records for monocytogenes inoculated 4-5

  1. Effect of Listeria monocytogenes inoculation, sodium acetate and ...

    African Journals Online (AJOL)

    Jane

    2011-08-08

    Aug 8, 2011 ... monocytogenes has been isolated from surface fresh waters and ... been reported that contamination of aquatic products with ..... In fish sausage treated with nisin, the peroxide value was lower in comparison with that of control (Raju et al., 2003). TBA assay is usually used as indicator for the assessment of.

  2. Inhibitory Effect of Nisin on Listeria monocytogenes Inoculated into Surimi and Minced Meat

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    Masoud Rezaei

    2012-02-01

    Full Text Available Background & Objective: Listeria monocytogenes has already established as an important food born pathogen which induce listeriosis in human. Use of bacteriocins to provide food safety has been increased dramatically. Nisin has a wide spectrum inhibitory effect than the other bacteriocins and inhibits food-borne pathogens such as L. monocytogenes and many other Gram-positive spoilage microorganisms. The purpose of this study was to investigate the inhibitory effect of Nisin on population of Listeria monocytogenes and the role of changes in food components on the antilisterial properties of Nisin. Materials & Methods: The minced meat and surimi samples were inoculated by 1×104 cfu/g of L. monocytogenes. Then samples exposed to Nisin at the levels of 500 or 1000 IU/g were prepared. All treatments after packaging in plastic bags were kept for 12 days at refrigerator temperature. Samples were cultured on CHROMagarTM Listeria every 2 days and the number of listeria monocytogenes was counted. Results: two different concentrations of Nisin (500 or 1000 IU/g was not able to inhibit L. monocytogenes below the acceptable level for raw food (100 cells per g in minced meat and surimi of silver carp. But the number of bacteria reduces more in fish surimi as compared to the mince meal. Also, antilisterial activity of Nisin was reduced during the storage period. Conclusion: Inhibitory property of Nisin against L. monocytogenes in surimi significantly was higher than the minced (P<0.05. So it is possible the antilisterial properties of Nisin will increase by elimination of some enzymes during processing.

  3. Effects of irradiation and fumaric acid treatment on the inactivation of Listeria monocytogenes and Salmonella typhimurium inoculated on sliced ham

    Science.gov (United States)

    Song, Hyeon-Jeong; Lee, Ji-Hye; Song, Kyung Bin

    2011-11-01

    To examine the effects of fumaric acid and electron beam irradiation on the inactivation of foodborne pathogens in ready-to-eat meat products, sliced ham was inoculated with Listeria monocytogenes and Salmonella typhimurium. The inoculated ham slices were treated with 0.5% fumaric acid or electron beam irradiation at 2 kGy. Fumaric acid treatment reduced the populations of L. monocytogenes and S. typhimurium by approximately 1 log CFU/g compared to control populations. In contrast, electron beam irradiation decreased the populations of S. typhimurium and L. monocytogenes by 3.78 and 2.42 log CFU/g, respectively. These results suggest that electron beam irradiation is a better and appropriate technique for improving the microbial safety of sliced ham.

  4. Effects of irradiation and fumaric acid treatment on the inactivation of Listeria monocytogenes and Salmonella typhimurium inoculated on sliced ham

    International Nuclear Information System (INIS)

    Song, Hyeon-Jeong; Lee, Ji-Hye; Song, Kyung Bin

    2011-01-01

    To examine the effects of fumaric acid and electron beam irradiation on the inactivation of foodborne pathogens in ready-to-eat meat products, sliced ham was inoculated with Listeria monocytogenes and Salmonella typhimurium. The inoculated ham slices were treated with 0.5% fumaric acid or electron beam irradiation at 2 kGy. Fumaric acid treatment reduced the populations of L. monocytogenes and S. typhimurium by approximately 1 log CFU/g compared to control populations. In contrast, electron beam irradiation decreased the populations of S. typhimurium and L. monocytogenes by 3.78 and 2.42 log CFU/g, respectively. These results suggest that electron beam irradiation is a better and appropriate technique for improving the microbial safety of sliced ham. - Highlights: → We compare irradiation and fumaric acid treatment on the inactivation of pathogens. → We examine changes in the populations of L. monocytogenes and S. typhimurium. → Irradiation at 2 kGy is more effective in sliced ham than fumaric acid treatment. → Low-dose irradiation can improve the microbial safety of sliced ham during storage.

  5. Effects of irradiation and fumaric acid treatment on the inactivation of Listeria monocytogenes and Salmonella typhimurium inoculated on sliced ham

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hyeon-Jeong; Lee, Ji-Hye [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Song, Kyung Bin, E-mail: kbsong@cnu.ac.kr [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2011-11-15

    To examine the effects of fumaric acid and electron beam irradiation on the inactivation of foodborne pathogens in ready-to-eat meat products, sliced ham was inoculated with Listeria monocytogenes and Salmonella typhimurium. The inoculated ham slices were treated with 0.5% fumaric acid or electron beam irradiation at 2 kGy. Fumaric acid treatment reduced the populations of L. monocytogenes and S. typhimurium by approximately 1 log CFU/g compared to control populations. In contrast, electron beam irradiation decreased the populations of S. typhimurium and L. monocytogenes by 3.78 and 2.42 log CFU/g, respectively. These results suggest that electron beam irradiation is a better and appropriate technique for improving the microbial safety of sliced ham. - Highlights: > We compare irradiation and fumaric acid treatment on the inactivation of pathogens. > We examine changes in the populations of L. monocytogenes and S. typhimurium. > Irradiation at 2 kGy is more effective in sliced ham than fumaric acid treatment. > Low-dose irradiation can improve the microbial safety of sliced ham during storage.

  6. Effect of several food ingredients on radiation inactivation of Escherichia coli and Listeria monocytogenes inoculated into ground pork

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyejeong [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lacroix, Monique [Canadian Irradiation Center, Research Laboratory in Science Applied to Food, INRS-Institut Armand-Frappier, Qebec (Canada); Jung, Samooel [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Keehyuk [Department of Culinary Nutrition, Woosong University, Daejeon 300-718 (Korea, Republic of); Lee, Ju Woon [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Jo, Cheorun, E-mail: cheorun@cnu.ac.kr [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2011-09-15

    The objective of this study was to examine the effects of several food ingredients on the relative radiation sensitivity (RRS) of Escherichia coli and Listeria monocytogenes inoculated onto ground pork. Garlic, leek, onion, and ginger were prepared in 3 different forms; pressurized, freeze-dried, and 70% ethanol extracted. The prepared food ingredients were subdivided into 2 groups, non-irradiated and irradiated with 5 kGy of gamma irradiation, before addition to ground pork. The prepared food ingredients were added at concentrations of 1% and 5% (w/w) into radiation-sterilized ground pork and inoculated with E. coli and L. monocytogenes (10{sup 6} CFU/mL). For E. coli inoculated pork, the most efficient ingredient was ethanol extracted leek (RRS=3.89), followed by freeze-dried ginger and leek (RRS=3.66 and 3.63, respectively) when used without pasteurization. However, when the food ingredients were irradiation-pasteurized, the freeze-dried ginger showed the highest RRS (4.10). When 5% natural materials were added, RRS was the highest for freeze-dried and ethanol extracted onion (4.44 and 4.65, respectively). For L. monocytogenes, the RRS was relatively lower than E. coli in general. The most efficient material was pressurized and freeze-dried onion (RRS=2.13 and 2.08, respectively) at a concentration of 1%. No increase in RRS was observed at increased concentration of food ingredients. These results suggest that the addition of particular food ingredients increased the efficiency of radiation-sterilization. However, changes in RRS were dependent on the species of microorganism as well as the form of the food ingredients. - Highlights: > Several food ingredients increased the efficiency of irradiation sterilization. > Different forms of food ingredients may affect the efficiency. > The increase of efficiency decreased the required irradiation dose, thereby avoiding sensory impairments of food.

  7. Effect of several food ingredients on radiation inactivation of Escherichia coli and Listeria monocytogenes inoculated into ground pork

    International Nuclear Information System (INIS)

    Yun, Hyejeong; Lacroix, Monique; Jung, Samooel; Kim, Keehyuk; Lee, Ju Woon; Jo, Cheorun

    2011-01-01

    The objective of this study was to examine the effects of several food ingredients on the relative radiation sensitivity (RRS) of Escherichia coli and Listeria monocytogenes inoculated onto ground pork. Garlic, leek, onion, and ginger were prepared in 3 different forms; pressurized, freeze-dried, and 70% ethanol extracted. The prepared food ingredients were subdivided into 2 groups, non-irradiated and irradiated with 5 kGy of gamma irradiation, before addition to ground pork. The prepared food ingredients were added at concentrations of 1% and 5% (w/w) into radiation-sterilized ground pork and inoculated with E. coli and L. monocytogenes (10 6 CFU/mL). For E. coli inoculated pork, the most efficient ingredient was ethanol extracted leek (RRS=3.89), followed by freeze-dried ginger and leek (RRS=3.66 and 3.63, respectively) when used without pasteurization. However, when the food ingredients were irradiation-pasteurized, the freeze-dried ginger showed the highest RRS (4.10). When 5% natural materials were added, RRS was the highest for freeze-dried and ethanol extracted onion (4.44 and 4.65, respectively). For L. monocytogenes, the RRS was relatively lower than E. coli in general. The most efficient material was pressurized and freeze-dried onion (RRS=2.13 and 2.08, respectively) at a concentration of 1%. No increase in RRS was observed at increased concentration of food ingredients. These results suggest that the addition of particular food ingredients increased the efficiency of radiation-sterilization. However, changes in RRS were dependent on the species of microorganism as well as the form of the food ingredients. - Highlights: → Several food ingredients increased the efficiency of irradiation sterilization. → Different forms of food ingredients may affect the efficiency. → The increase of efficiency decreased the required irradiation dose, thereby avoiding sensory impairments of food.

  8. Effect of several food ingredients on radiation inactivation of Escherichia coli and Listeria monocytogenes inoculated into ground pork

    Science.gov (United States)

    Yun, Hyejeong; Lacroix, Monique; Jung, Samooel; Kim, Keehyuk; Lee, Ju Woon; Jo, Cheorun

    2011-09-01

    The objective of this study was to examine the effects of several food ingredients on the relative radiation sensitivity (RRS) of Escherichia coli and Listeria monocytogenes inoculated onto ground pork. Garlic, leek, onion, and ginger were prepared in 3 different forms; pressurized, freeze-dried, and 70% ethanol extracted. The prepared food ingredients were subdivided into 2 groups, non-irradiated and irradiated with 5 kGy of gamma irradiation, before addition to ground pork. The prepared food ingredients were added at concentrations of 1% and 5% (w/w) into radiation-sterilized ground pork and inoculated with E. coli and L. monocytogenes (10 6 CFU/mL). For E. coli inoculated pork, the most efficient ingredient was ethanol extracted leek (RRS=3.89), followed by freeze-dried ginger and leek (RRS=3.66 and 3.63, respectively) when used without pasteurization. However, when the food ingredients were irradiation-pasteurized, the freeze-dried ginger showed the highest RRS (4.10). When 5% natural materials were added, RRS was the highest for freeze-dried and ethanol extracted onion (4.44 and 4.65, respectively). For L. monocytogenes, the RRS was relatively lower than E. coli in general. The most efficient material was pressurized and freeze-dried onion (RRS=2.13 and 2.08, respectively) at a concentration of 1%. No increase in RRS was observed at increased concentration of food ingredients. These results suggest that the addition of particular food ingredients increased the efficiency of radiation-sterilization. However, changes in RRS were dependent on the species of microorganism as well as the form of the food ingredients.

  9. Effectiveness of different antimicrobial washes combined with freezing against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes inoculated on blueberries

    Science.gov (United States)

    To ensure the microbial safety of produce including blueberries, sanitization is a critical step. This study evaluated the efficacy of sanitizers when coupled with frozen storage, in inactivating Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes inoculated on wild blueberri...

  10. Simultaneous and individual quantitative estimation of Salmonella, Shigella and Listeria monocytogenes on inoculated Roma tomatoes (Lycopersicon esculentum var. Pyriforme) and Serrano peppers (Capsicum annuum) using an MPN technique.

    Science.gov (United States)

    Cabrera-Díaz, E; Martínez-Chávez, L; Sánchez-Camarena, J; Muñiz-Flores, J A; Castillo, A; Gutiérrez-González, P; Arvizu-Medrano, S M; González-Aguilar, D G; Martínez-Gonzáles, N E

    2018-08-01

    Simultaneous and individual enumeration of Salmonella, Shigella and Listeria monocytogenes was compared on inoculated Roma tomatoes and Serrano peppers using an Most Probable Number (MPN) technique. Samples consisting of tomatoes (4 units) or peppers (8 units) were individually inoculated with a cocktail of three strains of Salmonella, Shigella or L. monocytogenes, or by simultaneous inoculation of three strains of each pathogen, at low (1.2-1.7 log CFU/sample) and high (2.2-2.7 log CFU/sample) inocula. Samples were analyzed by an MPN technique using universal pre-enrichment (UP) broth at 35 °C for 24 ± 2 h. The UP tubes from each MPN series were transferred to enrichment and plating media following adequate conventional methods for isolating each pathogen. Data were analyzed using multifactorial analysis of variance (p  simultaneous), type of bacteria (Salmonella > Shigella and L. monocytogenes), type of sample (UP broth > pepper and tomato), and inoculum level (high > low). The MPN technique was effective for Salmonella on both commodities. Shigella counts were higher on tomatoes compared to peppers, (p < 0.05), and for L. monocytogenes on peppers (p < 0.05). Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Chemical Composition, Antioxidant and Antimicrobial Activities of Thymus capitata Essential Oil with Its Preservative Effect against Listeria monocytogenes Inoculated in Minced Beef Meat

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    Nariman El Abed

    2014-01-01

    Full Text Available The chemical composition, antioxidant and antimicrobial activities, and the preservative effect of Thymus capitata essential oil against Listeria monocytogenes inoculated in minced beef meat were evaluated. The essential oil extracted was chemically analyzed by gas chromatography-mass spectrometry. Nineteen components were identified, of which carvacrol represented (88.89% of the oil. The antioxidant activity was assessed in vitro by using both the DPPH and the ABTS assays. The findings showed that the essential oil exhibited high antioxidant activity, which was comparable to the reference standards (BHT and ascorbic acid with IC50 values of 44.16 and 0.463 μg/mL determined by the free-radical scavenging DPPH and ABTS assays, respectively. Furthermore, the essential oil was evaluated for its antimicrobial activity using disc agar diffusion and microdilution methods. The results demonstrated that the zone of inhibition varied from moderate to strong (15–80 mm and the minimum inhibition concentration values ranged from 0.32 to 20 mg/mL. In addition, essential oil evaluated in vivo against Listeria monocytogenes showed clear and strong inhibitory effect. The application of 0.25 or 1% (v/w essential oil of T. capitata to minced beef significantly reduced the L. monocytogenes population when compared to those of control samples (P-value  <0.01.

  12. Citrus lemon essential oil: chemical composition, antioxidant and antimicrobial activities with its preservative effect against Listeria monocytogenes inoculated in minced beef meat.

    Science.gov (United States)

    Ben Hsouna, Anis; Ben Halima, Nihed; Smaoui, Slim; Hamdi, Naceur

    2017-08-03

    Lemon (Citrus limon) is a flowing plant belonging to the Rutaceae family. Citrus plants constitute one of the main valuable sources of essential oil used in foods and medicinal purposes. In this study, we assessed chemical composition, antioxidant and antimicrobial activities of C. limon essential oil (ClEO) with its preservative effect against Listeria monocytogenes inoculated in minced beef meat. Gas chromatography/mass spectrometry (GC-MS) was used to identify the major components of the obtained ClEO. The antioxidant activities of this ClEO were determined according to the β-carotene bleaching assay, as well as by 2.2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. For antimicrobial activity, agar well diffusion method was used and the minimum inhibitory concentrations (MICs) as well as the minimum fungicidal concentrations (MFCs) were determined. The in situ effect of the ClEO was evaluated through physicochemical parameters (pH and thiobarbituric acid reactive substances (TBARS), as well as against L. monocytogenes in minced beef meat model. Twenty one components were identified in the ClEO and the two dominant compounds were limonene (39.74%) and β-Pinene (25.44%). This ClEO displayed an excellent DPPH scavenging ability with an extract concentration providing 50% inhibition (IC 50 ) of 15.056 μg/ml and a strong β-carotene bleaching inhibition after 120 min of incubation with an IC 50 of 40.147 μg/ml. The MICs varied from 0.039 to 1.25 mg/ml for Gram positive bacteria and from 0.25 to 2.5 mg/ml for Gram-negative bacteria. The meat preserving potential of ClEO was investigated against L. monocytogenes. ClEO successfully inhibited development of L. monocytogenes in minced beef meat. The application of ClEO at a 0.06 and 0.312 mg/g, may open new promising opportunities for the prevention of contamination from and growth of pathogenic bacteria, particularly L. monocytogenes, during minced beef meat storage at 4 °C. Additionally, during

  13. Inhibitory activity of Syzygium aromaticum and Cymbopogon citratus (DC. Stapf. essential oils against Listeria monocytogenes inoculated in bovine ground meat

    Directory of Open Access Journals (Sweden)

    Thales Leandro Coutinho de Oliveira

    2013-01-01

    Full Text Available This research evaluated the antimicrobial effect of the clove (Syzygium aromaticum and lemongrass (Cymbopogon citratus (DC. Stapf. essential oils (EOs against Listeria monocytogenes ATCC 19117 growth added to bovine ground meat stored under refrigeration (5 ± 2 °C for three days. The EOs, extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS, were tested in vitro using an agar well diffusion methodology for determination of Minimum Inhibitory Concentration (MIC. The MIC concentrations for both essential oils on culture tested of L. monocytogenes were 1.56%. The EOs concentrations applied in contaminated ground beef were 1.56, 3.125 and 6.25% (w/v based on MIC levels and possible activity reductions by food constituents. The bacteria populations were significantly reduced (p < 0.05 after one day of storage in ground meat samples treated with clove and lemongrass EOs at concentrations of 1.56%. There were no significant counts of L. monocytogenes in samples at the other concentrations of the two oils applied after the second day of storage. The sensory acceptability evaluation of the bovine ground meat samples treated with EOs showed that the addition at concentrations higher than 1.56% promote undesirable alterations of taste, odor and characteristic color. The application of EOs at low concentrations in food products can be used in combination with other preservation methods, such as refrigeration, to control pathogens and spoilage bacteria during shelf-life; which goes according to current market trends, where consumers are requesting natural products.

  14. Inhibitory activity of Syzygium aromaticum and Cymbopogon citratus (DC.) Stapf. essential oils against Listeria monocytogenes inoculated in bovine ground meat.

    Science.gov (United States)

    de Oliveira, Thales Leandro Coutinho; das Graças Cardoso, Maria; de Araújo Soares, Rodrigo; Ramos, Eduardo Mendes; Piccoli, Roberta Hilsdorf; Tebaldi, Victor Maximiliano Reis

    2013-01-01

    This research evaluated the antimicrobial effect of the clove (Syzygium aromaticum) and lemongrass (Cymbopogon citratus (DC.) Stapf.) essential oils (EOs) against Listeria monocytogenes ATCC 19117 growth added to bovine ground meat stored under refrigeration (5 ± 2 °C) for three days. The EOs, extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), were tested in vitro using an agar well diffusion methodology for determination of Minimum Inhibitory Concentration (MIC). The MIC concentrations for both essential oils on culture tested of L. monocytogenes were 1.56%. The EOs concentrations applied in contaminated ground beef were 1.56, 3.125 and 6.25% (w/v) based on MIC levels and possible activity reductions by food constituents. The bacteria populations were significantly reduced (p ≤ 0.05) after one day of storage in ground meat samples treated with clove and lemongrass EOs at concentrations of 1.56%. There were no significant counts of L. monocytogenes in samples at the other concentrations of the two oils applied after the second day of storage. The sensory acceptability evaluation of the bovine ground meat samples treated with EOs showed that the addition at concentrations higher than 1.56% promote undesirable alterations of taste, odor and characteristic color. The application of EOs at low concentrations in food products can be used in combination with other preservation methods, such as refrigeration, to control pathogens and spoilage bacteria during shelf-life; which goes according to current market trends, where consumers are requesting natural products.

  15. Viability of Listeria monocytogenes surface inoculated onto slices of pork scrapple during storage at 4 Degrees, 10 Degrees, and 21 Degrees C

    Science.gov (United States)

    We evaluated the fate of Listeria monocytogenes on scrapple, a regionally-popular, ready-to-eat (RTE) savory mush of pork trimmings, cornmeal, and flour. We also conducted an informal survey to address consumer practices for storing and reheating scrapple. Regarding the survey, of some 125 consumers...

  16. CHALLENGE TESTS WITH LISTERIA MONOCYTOGENES IN SALAMI: PRELIMINARY RESULTS

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    R. Mioni

    2013-02-01

    Full Text Available Challenge tests are the preferable methodology to study the behaviour of Listeria monocytogenes on ready to eat foods, according to Regulation (EC 2073/2005. Challenge testing using L. monocytogenes in seasoned salami from different food business operators showed, after seasoning of the product, a count reduction of the inoculated organisms without any further growth of the pathogen; however differences of L. monocytogenes behaviour could be observed according to different production protocols.

  17. In vitro activity of naturally occurring peptides (defensins against Listeria monocytogenes Ação in vitro de peptídeos naturais (defensinas sobre Listeria monocytogenes

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    Maria da Graça F. Nascimento

    1994-12-01

    Full Text Available Autoclaved distilled water samples were inoculated with L. monocytogenes strain V7 and strain VPH-1, and incubated aerobically, at 30 C for 48 hours. Each strain was tested individually, and growth curves were determined at 1, 2, 3, 4, 5, 21, 24, and 48 hours. The growth or survival of L. monocytogenes was similar for both strains, with survivors at 24 hour-incubation. The microbicidal activity of one synthetic cationic peptide (NP-2 was examined against L. monocytogenes strain V7, in a water system. Antibacterial activity of NP-2 (1, 5, and 10 g/ml was best expressed at 60 minute-incubation, with 10 g/ml of peptide, at 30 C.Amostras de água destilada, autoclavadas, foram inoculadas com L. monocytogenes cepa V7 e cepa VPH-1, e incubadas, aerobicamente, a 30ºC por 48 horas. Cada cepa foi testada individualmente, e determinou-se curvas de crescimento a 1, 2, 3, 4, 5, 21, 24, e 48 horas. O crescimento ou sobrevivência das duas cepas foi semelhante e encontrou-se sobreviventes em 24 horas de incubação. Examinou-se a atividade bactericida de um dos peptídeos catiônicos sintéticos (NP-2 contra L. monocytogenes cepa V7, em sistema aquoso. A atividade antibacteriana de NP-2 (1, 5, and 10µg/ml foi melhor aos 60 minutos de incubação, com 10µg/ml de peptídeo, a 30 C.

  18. LISTERIA MONOCYTOGENES RISK EVALUATION IN READY TO EAT DELI PRODUCTS

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    T Civera

    2013-02-01

    Full Text Available Listeria monocytogenes has become one of the major concerns for food safety. Its ability to survive and replicate at low temperature, pH and high salt concentration, makes the bacterium a threat, mostly for RTE products. For these reasons, the present research was aimed at detecting the ability of growth of L. monocytogenes in RTE products retrieved from one deli store. Samples were analysed for L. monocytogenes detection, then inoculated with the pathogen (105cell/ml and stored at refrigeration temperature for the duration of their shelf-life (15-60 days. In all the products L. monocytogenes was not detected before experimental contamination. The challenge test evidenced that experimentally inoculated L. monocytogenes was not able to multiply for the duration of the entire shelf-life. These results indicated that the tested products could be considered as foods which are not able to support the growth of L. monocytogenes, as indicated by E.C. Regulation 2073/05. However, in order to guarantee consumer’s safety, it needs to be emphasized the need of a correct application of the GMPs, required for lowering the risk of initial contamination.

  19. Incidence of Listeria monocytogenes and Other Bacteria in ...

    African Journals Online (AJOL)

    Prof. Ogunji

    Abstract. The involvement of Listeria monocytogenes in spontaneous abortion in Jos was investigated. One hundred blood and 100 placenta samples were collected from spontaneous abortion patients in Jos. The samples were inoculated first into Listeria enrichment broth. Incubation was at 37o C, followed by cold ...

  20. Incidence of Listeria monocytogenes and Other Bacteria in ...

    African Journals Online (AJOL)

    The involvement of Listeria monocytogenes in spontaneous abortion in Jos was investigated. One hundred blood and 100 placenta samples were collected from spontaneous abortion patients in Jos. The samples were inoculated first into Listeria enrichment broth. Incubation was at 37o C, followed by cold enrichment at ...

  1. Lactobacillus plantarum inhibits growth of Listeria monocytogenes in an in vitro continuous flow gut model, but promotes invasion of L. monocytogenes in the gut of gnotobiotic rats

    DEFF Research Database (Denmark)

    Bernbom, Nete; Licht, Tine Rask; Saadbye, Peter

    2006-01-01

    The ability of the pediocin AcH producing Lactobacillus plantarum DDEN 11007 and its non-producing plasmid-cured isogenic variant, DDEN 12305 to prevent the persistence and growth of Listeria monocytogenes EP2 in two gastrointestinal (GI) tract models was examined. In vitro studies conducted...... in a two-stage continuous flow system showed that L. plantarum DDEN 11007 inhibited L. monocytogenes EP2 under these conditions, while less effect was seen of the non-bacteriocin producing variant. The inhibitory effect was more pronounced at pH 5 than at pH 7. No effect on persistence of L. monocytogenes...... in the GI tract was seen in gnotobiotic rats colonized with either the pediocin AcH producing or the non-bacteriocin producing variant of L. plantarum when compared to rats inoculated with L. monocytogenes EP2 alone. Surprisingly, inoculation of the gnotobiotic animals with either of the L. plantarum...

  2. Effect of starter cultures on survival of Listeria monocytogenes in Čajna sausage

    Science.gov (United States)

    Bošković, M.; Tadić, V.; Đorđević, J.; Glišić, M.; Lakićević, B.; Dimitrijević, M.; Baltić, M. Ž.

    2017-09-01

    The aim of the study was to evaluate the survival of Listeria monocytogenes during the production of Čajna sausage with short maturation time. Sausage batter was inoculated with three different serotypes 4b and serotype 1/2a of L. monocytogenes. Control sausages were without any starter culture added; the second batch was inoculated with strains of Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus, and the third batch was inoculated with strains of Debaryomyces hansenii, Lactobacillus sakei, Pediococcus acidilactici, Pediococcus pentosaceus, Staphylococcus carnosus and Staphylococcus xylosus. After 18 days of ripening, L. monocytogenes was not detected in any of the sausages, but during this fermentation and drying, the numbers of this pathogen was lower in the sausages inoculated with starter cultures.

  3. Effect of a bacteriophage cocktail in combination with modified atmosphere packaging in controlling Listeria monocytogenes on fresh-cut spinach

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    Boyacioglu O.

    2016-06-01

    Full Text Available A Listeria monocytogenes-specific bacteriophage cocktail was evaluated for its activity against a nalidixic acid-resistant L. monocytogenes (Lm-NalR isolate on fresh-cut spinach stored under modified atmosphere packaging at various temperatures. Pieces (~2 × 2 cm2 of fresh spinach inoculated with 4.5 log CFU/cm2 Lm-NalR were sprayed with the phage cocktail (6.5 log plaque-forming units [PFU]/cm2 or a control. The samples were stored at 4°C or 10°C for up to 14 d in sealed packages filled with either atmospheric air (AA or modified atmosphere (MA. At 4°C under AA, the phages significantly (P ≤ 0.05 lowered the Lm-NalR populations on spinach, compared to control-treated inoculated samples, by 1.12 and 1.51 log CFU/cm2 after 1 and 14 d, respectively. At 4°C under MA, Lm-NalR was significantly reduced by 1.95 log CFU/cm2 compared to control leaves after both 1 and 14 d. At 10°C under AA, the phages significantly reduced Lm-NalR by 1.50 and 2.51 log CFU/cm2 after 1 and 14 d compared to the control. Again at 10°C under MA, the phages significantly reduced Lm-NalR by 1.71 and 3.24 log CFU/cm2 compared to control after 1 and 14 d, respectively. The results support the potential of lytic bacteriophages in effectively reducing populations of L. monocytogenes on freshcut leafy produce, under both AA and MA conditions.

  4. Effect of co-culture with enterocinogenic E. faecium on L. monocytogenes key virulence gene expression

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    Eleftherios H. Drosinos

    2016-08-01

    Full Text Available The aim of the present study was to assess the expression of key virulence genes during co-culture of L. monocytogenes with a bacteriocinogenic E. faecium strain in liquid growth medium. For that purpose, BHI broth was inoculated with 7 log CFU·mL–1 L. monocytogenes and 4, 5 or 6 log CFU·mL–1 E. faecium. Sampling took place after 8 and 24 h of incubation, corresponding to the maximum and minimum of enterocin production, respectively. The RNA was extracted, stabilized and expression of prfA, sigB, hly, plcA, plcB, inlA, inlB, inlC and inlJ, was assessed by RT-qPCR. Most of the genes were downregulated during co-culture at 5 °C. Moreover, a statistically significant effect of the inoculum level was evident in most of the cases. On the contrary, no effect on the transcription level of most of the genes was observed during co-culture at 37 °C.

  5. Behaviour of Listeria monocytogenes in packaged fresh mushrooms (Agaricus bisporus).

    Science.gov (United States)

    González-Fandos, E; Olarte, C; Giménez, M; Sanz, S; Simón, A

    2001-11-01

    The aim of this study was to evaluate the potential of Listeria monocytogenes to grow in mushrooms packaged in two different types of PVC films when stored at 4 degrees C and 10 degrees C. Mushrooms were packed in two polymeric films (perforated and nonperforated PVC) and stored at 4 degrees C and 10 degrees C. The carbon dioxide and oxygen content inside the packages, aerobic mesophiles, psychrotrophs, Pseudomonas spp., Listeria monocytogenes, faecal coliforms, Escherichia coli, anaerobic spores and major sensory factors were determined. The mushrooms packaged in nonperforated film and stored at 4 degrees C had the most desirable quality parameters (texture, development stage and absence of moulds). Listeria monocytogenes was able to grow at 4 degrees C and 10 degrees C in inoculated mushrooms packaged in perforated and nonperforated films between 1 and 2 log units during the first 48 h. After 10 d of storage, the populations of L. monocytogenes were higher in mushrooms packaged in nonperforated film and stored at 10 degrees C. MAP followed by storage at 4 degrees C or 10 degrees C extends the shelf life by maintaining an acceptable appearance, but allows the growth and survival of L. monocytogenes. According to this study additional hurdles must be studied in order to prevent the growth of L. monocytogenes.

  6. Inactivation of Listeria monocytogenes in milk by pulsed electric field.

    Science.gov (United States)

    Reina, L D; Jin, Z T; Zhang, Q H; Yousef, A E

    1998-09-01

    Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25 degrees C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50 degrees C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

  7. Animal models for oral transmission of Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Sarah E F D'Orazio

    2014-02-01

    Full Text Available Listeria monocytogenes has been recognized as a food borne pathogen in humans since the 1980s, but we still understand very little about oral transmission of L. monocytogenes or the host factors that determine susceptibility to gastrointestinal infection, due to the lack of an appropriate small animal model of oral listeriosis. Early feeding trials suggested that many animals were highly resistant to oral infection, and the more reproducible intravenous or intraperitoneal routes of inoculation soon came to be favored. There are a fair number of previously published studies using an oral infection route, but the work varies widely in terms of bacterial strain choice, the methods used for oral transmission, and various manipulations used to enhance infectivity. This mini review will summarize the published literature using oral routes of L. monocytogenes infection and will highlight recent technological advances that have made oral infection a more attractive model system.

  8. Viable but non-culturable Listeria monocytogenes on parsley leaves and absence of recovery to a culturable state.

    Science.gov (United States)

    Dreux, N; Albagnac, C; Federighi, M; Carlin, F; Morris, C E; Nguyen-the, C

    2007-10-01

    To investigate the presence of viable but non-culturable Listeria monocytogenes during survival on parsley leaves under low relative humidity (RH) and to evaluate the ability of L. monocytogenes to recover from VBNC to culturable state under satured humidity. Under low RH (47-69%) on parsley leaves, the initial number of L. monocytogenes populations counted on non selective media (10(9) L. monocytogenes per leaf on TSA) was reduced by 6 log10 scales in 15 days, whereas number of viable L. monocytogenes counted under the microscope was reduced by 3-4 log10 scales, indicating the presence of VBNC cells. This was demonstrated on three L. monocytogenes strains (EGDe, Bug 1995 and LmP60). Changing from low to 100% RH permitted an increase of the culturable counts of L. monocytogenes and this growth was observed only when residual culturable cells were present. Moreover, VBNC L. monocytogenes inoculated on parsley leaves did not become culturable after incubation under 100% RH. Dry conditions induced VBNC L. monocytogenes on parsley leaves but these VBNC were likely unable to recover culturability after transfer to satured humidity. Enumeration on culture media presumably under-estimates the number of viable L. monocytogenes on fresh produce after exposure to low RH.

  9. Commensal microbes provide first line defense against Listeria monocytogenes infection

    Science.gov (United States)

    Littmann, Eric R.; Kim, Sohn G.; Morjaria, Sejal M.; Ling, Lilan; Gyaltshen, Yangtsho; Taur, Ying; Leiner, Ingrid M.

    2017-01-01

    Listeria monocytogenes is a foodborne pathogen that causes septicemia, meningitis and chorioamnionitis and is associated with high mortality. Immunocompetent humans and animals, however, can tolerate high doses of L. monocytogenes without developing systemic disease. The intestinal microbiota provides colonization resistance against many orally acquired pathogens, and antibiotic-mediated depletion of the microbiota reduces host resistance to infection. Here we show that a diverse microbiota markedly reduces Listeria monocytogenes colonization of the gut lumen and prevents systemic dissemination. Antibiotic administration to mice before low dose oral inoculation increases L. monocytogenes growth in the intestine. In immunodeficient or chemotherapy-treated mice, the intestinal microbiota provides nonredundant defense against lethal, disseminated infection. We have assembled a consortium of commensal bacteria belonging to the Clostridiales order, which exerts in vitro antilisterial activity and confers in vivo resistance upon transfer into germ free mice. Thus, we demonstrate a defensive role of the gut microbiota against Listeria monocytogenes infection and identify intestinal commensal species that, by enhancing resistance against this pathogen, represent potential probiotics. PMID:28588016

  10. Listeria monocytogenes: diagnostic problems

    NARCIS (Netherlands)

    Beumer, R.R.; Hazeleger, W.C.

    2003-01-01

    The first isolation methods for the detection of Listeria spp. were generally based on the direct culture of samples on simple agar media, but isolation of the pathogenic Listeria monocytogenes was difficult. In time, new techniques were developed, based on a variety of selective and elective agents

  11. [Analysis of antibiotic susceptibility of foodborne Listeria monocytogenes in China].

    Science.gov (United States)

    Yang, Yang; Fu, Ping; Guo, Yunchang; Liu, Xiurmei

    2008-03-01

    To study the antibiotic susceptibility of foodborne Listeria monocytogenes in China. The susceptibilities of 476 strains of foodborne Listeria monocytogenes to antibiotics were determined in Broth Microdilution Susceptibility Testing in Clinical and Laboratory Standards Institute. The antibiotics of gentamicin, ampicillin, penicillin, tetracycline, doxycycline, imipenem, erythromycin, ciprofloxacin, levofloxacin, cephalothin, rifampin, vancomycin, chloramphenicol, Trimethoprim-sulfamethoxazole, ampicillin-sulbactam were used. The rates of antibiotic resistance in 467 is olates were 4.5%. Tetracycline resistance was most prevalent, accouting for 4.07% . The foods that the rates of antibiotic resistance were highest were vegetable (10%). Among 14 provinces, Jilin, Hubei and Hebei were the third top, the rate of which were 19.6% and 9.1% and 8%, respectively. It was suggested that antibiotic resistance exists in foodborne Listeria monocytogenes to a certain extent in China. It should pay more attention to the use of drugs in prevention and clinic treatment to reduce the antibiotic resistant strains.

  12. Efficacy of chlorine dioxide against Listeria monocytogenes in brine chilling solutions.

    Science.gov (United States)

    Valderrama, W B; Mills, E W; Cutter, C N

    2009-11-01

    Chilled brine solutions are used by the food industry to rapidly cool ready-to-eat meat products after cooking and before packaging. Chlorine dioxide (ClO(2)) was investigated as an antimicrobial additive to eliminate Listeria monocytogenes. Several experiments were performed using brine solutions made of sodium chloride (NaCl) and calcium chloride (CaCl(2)) inoculated with L. monocytogenes and/or treated with 3 ppm of ClO(2). First, 10 and 20% CaCl(2) and NaCl solutions (pH 7.0) were inoculated with a five-strain cocktail of L. monocytogenes to obtain approximately 7 log CFU/ml and incubated 8 h at 0 degrees C. The results demonstrated that L. monocytogenes survived in 10% CaCl(2), 10 and 20% NaCl, and pure water. L. monocytogenes levels were reduced approximately 1.2 log CFU/ml in 20% CaCl(2). Second, inoculated ( approximately 7 log CFU/ml) brine solutions (10 and 20% NaCl and 10% CaCl(2)) treated with 3 ppm of ClO(2) resulted in a approximately 4-log reduction of the pathogen within 90 s. The same was not observed in a solution of 20% CaCl(2); further investigation demonstrated that high levels of divalent cations interfere with the disinfectant. Spent brine solutions from hot dog and ham chilling were treated with ClO(2) at concentrations of 3 or 30 ppm. At these concentrations, ClO(2) did not reduce L. monocytogenes. Removal of divalent cations and organic material in brine solutions prior to disinfection with ClO(2) should be investigated to improve the efficacy of the compound against L. monocytogenes. The information from this study may be useful to processing establishments and researchers who are investigating antimicrobials in chilling brine solutions.

  13. Thermal inactivation of Listeria monocytogenes and Salmonella spp. in sous-vide processed marinated chicken breast

    Science.gov (United States)

    The heat resistance of a cocktail of five Salmonella strains and five L. monocytogenes strains was determined in teriyaki-marinated chicken breasts. Inoculated meat, packaged in bags, were completely immersed in a circulating water bath and cooked to a final temperature of 55, 57.5 or 60C in one h...

  14. Efficacy of ultraviolet light exposure against survival of Listeria monocytogenes on conveyor belts.

    Science.gov (United States)

    Morey, Amit; McKee, Shelly R; Dickson, James S; Singh, Manpreet

    2010-06-01

    Listeria monocytogenes has been repeatedly isolated from foods and food-processing facilities including food contact surfaces such as conveyor belts (CB). CBs are often difficult to clean and require rigorous sanitation programs for decontamination. Ultraviolet (UV) light has exhibited microbicidal properties on food contact surfaces and this study was conducted to determine the efficacy of UV against L. monocytogenes on CB made of different materials. A four-strain cocktail of L. monocytogenes (serotypes 3A, 4A, 4B, and 4C) was made to give a suspension of approximately 10(7) CFU/mL. CBs made from four different types of materials, (1) Ropanyl DM 8/2 A2 + 04 (belt 1), (2) Volta FRMW-3.0 (belt 2), (3) Volta FRMB-3.0 (belt 3), and (4) Ropanyl DM (belt 4), were inoculated with 1 mL of the four-strain cocktail (approximately 10(7) CFU/mL) of the bacterial suspension. CBs were treated with UV light (254 nm) for 1 and 3 sec at 5.53 and 5.95 mW/cm(2). Three replications of the experiments were conducted. Two-way analysis of variance of survival populations of L. monocytogenes showed that bacterial counts were significantly reduced (p belt types irrespective of UV light intensities and times of exposure. L. monocytogenes populations were reduced (p belts 1, 2, and 3 after exposure to 5.95 mW/cm(2) UV light intensity for 3 sec. L. monocytogenes-inoculated CBs that were exposed to 5.53 mW/cm(2) showed higher (p Belt 4 showed survival populations of L. monocytogenes ranging from 1.42 to 1.73 log(10) CFU/cm(2) after UV light treatment for 1 and 3 sec. UV light can be effectively used to reduce L. monocytogenes contamination on CBs.

  15. Control of Listeria monocytogenes in turkey deli loaves using organic acids as formulation ingredients.

    Science.gov (United States)

    Lloyd, T; Alvarado, C Z; Brashears, M M; Thompson, L D; McKee, S R; Berrang, M

    2009-10-01

    The growth of Listeria monocytogenes in further-processed meat products has become a major concern and an important food safety issue. The meat and poultry industries have incorporated interventions such as organic acids in marinades to inhibit the growth of L. monocytogenes. In this study, organic acids were utilized in the raw product and as a postcook dip to determine their inhibitory effect on the growth of L. monocytogenes in turkey deli loaves. The turkey deli loaves were processed, cooked, cooled, inoculated with streptomycin-resistant L. monocytogenes, and then dipped. Treatments were potassium lactate (PL) in the raw product with sodium lactate (SL), sodium diacetate (SD) dip, PL with SL/PL/SD dip, SL with SL/SD dip, and SL with SL/PL/SD dip. There was also a positive (inoculated) and negative (noninoculated) control, which was dipped in distilled water. Days 0, 7, 14, 21, 28, 42, and 56 were sampled for L. monocytogenes. There were no differences (P>0.05) among the organic acid treatments in the turkey deli loaves at any time points; therefore, all of the treatments increased the lag phase of L. monocytogenes, extending the shelf-life of the product. However, there was a difference between the treatments and the positive control at d 7, 14, 21, 28, 42, and 56. The growth of L. monocytogenes increased immediately in the positive control, whereas the negative control appeared to have no growth. These organic acids can provide meat processors with a useful method for extending the lag phase of L. monocytogenes in ready-to-eat meat and poultry products.

  16. Effect of Listeria seeligeri or Listeria welshimeri on Listeria monocytogenes detection in and recovery from buffered Listeria enrichment broth.

    Science.gov (United States)

    Dailey, Rachel C; Welch, Lacinda J; Hitchins, Anthony D; Smiley, R Derike

    2015-04-01

    The presence of multiple species of Listeria in regulated food products is not uncommon and can complicate the recovery of Listeria monocytogenes particularly on a non-differentiating medium. The potential complications of Listeria seeligeri and Listeria welshimeri on the recovery of L. monocytogenes from inoculated food test samples using the U.S. Food and Drug Administration's (FDA) selective enrichment procedure was investigated. Post-enrichment enumeration, in the absence of food product, indicates that some L. seeligeri and L. monocytogenes pairings may have population differentials as great as 2.7 ± 0.1 logs with L. seeligeri being the predominant species. A similar observation was noted for L. welshimeri and L. monocytogenes pairings which resulted in population differentials as large as 3.7 ± 0.2 logs with L. welshimeri being the predominant species. Select strain pairings were used to inoculate guacamole, crab meat, broccoli, and cheese with subsequent recovery by the FDA Bacteriological Analytical Manual (BAM) method with 10 colonies per sample selected for confirmation. The presence of L. seeligeri had little effect on the recovery of L. monocytogenes. The presence of L. welshimeri resulted in the failure to recover L. monocytogenes in three out of the four food matrices. This work extends the observation that non-pathogenic species of Listeria can complicate the recovery of L. monocytogenes and that competition during selective enrichment is not limited to the presence of just Listeria innocua. Published by Elsevier Ltd.

  17. Effect of Listeria seeligeri or Listeria welshimeri on Listeria monocytogenes detection in and recovery from buffered Listeria enrichment broth☆

    Science.gov (United States)

    Dailey, Rachel C.; Welch, Lacinda J.; Hitchins, Anthony D.; Smiley, R. Derike

    2016-01-01

    The presence of multiple species of Listeria in regulated food products is not uncommon and can complicate the recovery of Listeria monocytogenes particularly on a non-differentiating medium. The potential complications of Listeria seeligeri and Listeria welshimeri on the recovery of L. monocytogenes from inoculated food test samples using the U.S. Food and Drug Administration's (FDA) selective enrichment procedure was investigated. Post-enrichment enumeration, in the absence of food product, indicates that some L. seeligeri and L. monocytogenes pairings may have population differentials as great as 2.7 ± 0.1 logs with L. seeligeri being the predominant species. A similar observation was noted for L. welshimeri and L. monocytogenes pairings which resulted in population differentials as large as 3.7 ± 0.2 logs with L. welshimeri being the predominant species. Select strain pairings were used to inoculate guacamole, crab meat, broccoli, and cheese with subsequent recovery by the FDA Bacteriological Analytical Manual (BAM) method with 10 colonies per sample selected for confirmation. The presence of L. seeligeri had little effect on the recovery of L. monocytogenes. The presence of L. welshimeri resulted in the failure to recover L. monocytogenes in three out of the four food matrices. This work extends the observation that non-pathogenic species of Listeria can complicate the recovery of L. monocytogenes and that competition during selective enrichment is not limited to the presence of just Listeria innocua. PMID:25475325

  18. Listeria monocytogenes Monographic Study

    Directory of Open Access Journals (Sweden)

    Emil Tirziu

    2010-05-01

    Full Text Available Listeria monocytogenes is a ubiquitous bacteria with a remarkable resistance in discordant condition which produce listeriosis, an infectious disease that affects multiple domestic and wild animals’ species, but also humans. Receptive to listeriosis are the majority of domestic or wild mammals and birds, in the last years being registered an increase of receptivity in humans. The concept of listeriosis in human pathology, a disease caused by eating or drinking contaminated food and water, appeared for the first time in 1981, during an outbreak in Canada with seven cases in adults and 34 cases of maternalfetal listeriosis. The alimentary origin of human listeriosis can be easily explained if considered some general characteristics of the bacteria. Thus, resistance in various conditions, especially at lower temperatures, justifies its dissemination and food contamination, particularly when is conserved by refrigeration. Also, L. monocytogenes has a significant presence in alimentary products. Some studies showed that 4% of the milk products, 29% of the meat products, 5% of the vegetable products and 26% of the products obtained from fishes and shell fishes are positive for L. monocytogenes, which allows us to say that battle against these bacteria is a war against microbial contamination.

  19. 27 CFR 4.5 - Related regulations.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Related regulations. 4.5 Section 4.5 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Scope § 4.5 Related regulations. The following...

  20. Growth characteristics of Listeria monocytogenes as affected by a native microflora in cooked ham under refrigerated and temperature abuse conditions.

    Science.gov (United States)

    Hwang, Cheng-An; Sheen, Shiowshuh

    2011-05-01

    This study examined the growth characteristics of Listeria monocytogenes as affected by a native microflora in cooked ham at refrigerated and abuse temperatures. A five-strain mixture of L. monocytogenes and a native microflora, consisting of Brochothrix spp., isolated from cooked meat were inoculated alone (monocultured) or co-inoculated (co-cultured) onto cooked ham slices. The growth characteristics, lag phase duration (LPD, h), growth rate (GR, log(10) cfu/h), and maximum population density (MPD, log(10) cfu/g), of L. monocytogenes and the native microflora in vacuum-packed ham slices stored at 4, 6, 8, 10, and 12 °C for up to 5 weeks were determined. At 4-12 °C, the LPDs of co-cultured L. monocytogenes were not significantly different from those of monocultured L. monocytogenes in ham, indicating the LPDs of L. monocytogenes at 4-12 °C were not influenced by the presence of the native microflora. At 4-8 °C, the GRs of co-cultured L. monocytogenes (0.0114-0.0130 log(10) cfu/h) were statistically but marginally lower than those of monocultured L. monocytogenes (0.0132-0.0145 log(10) cfu/h), indicating the GRs of L. monocytogenes at 4-8 °C were reduced by the presence of the native microflora. The GRs of L. monocytogenes were reduced by 8-7% with the presence of the native microflora at 4-8 °C, whereas there was less influence of the native microflora on the GRs of L. monocytogenes at 10 and 12 °C. The MPDs of L. monocytogenes at 4-8 °C were also reduced by the presence of the native microflora. Data from this study provide additional information regarding the growth suppression of L. monocytogenes by the native microflora for assessing the survival and growth of L. monocytogenes in ready-to-eat meat products. Published by Elsevier Ltd.

  1. Morphological Change and Decreasing Transfer Rate of Biofilm-Featured Listeria monocytogenes EGDe.

    Science.gov (United States)

    Lee, Yuejia; Wang, Chinling

    2017-03-01

    Listeria monocytogenes , a lethal foodborne pathogen, has the ability to resist the hostile food processing environment and thus frequently contaminates ready-to-eat foods during processing. It is commonly accepted that the tendency of L. monocytogenes ' to generate biofilms on various surfaces enhances its resistance to the harshness of the food processing environment. However, the role of biofilm formation in the transferability of L. monocytogenes EGDe remains controversial. We examined the growth of Listeria biofilms on stainless steel surfaces and their effect on the transferability of L. monocytogenes EGDe. The experiments were a factorial 2 × 2 design with at least three biological replicates. Through scanning electron microscopy, a mature biofilm with intensive aggregates of cells was observed on the surface of stainless steel after 3 or 5 days of incubation, depending on the initial level of inoculation. During biofilm development, L. monocytogenes EGDe carried out binary fission vigorously before a mature biofilm was formed and subsequently changed its cellular morphology from rod shaped to sphere shaped. Furthermore, static biofilm, which was formed after 3 days of incubation at 25°C, significantly inhibited the transfer rate of L. monocytogenes EGDe from stainless steel blades to 15 bologna slices. During 7 days of storage at 4°C, however, bacterial growth rate was not significantly impacted by whether bacteria were transferred from biofilm and the initial concentrations of transferred bacteria on the slice. In conclusion, this study is the first to report a distinct change in morphology of L. monocytogenes EGDe at the late stage of biofilm formation. More importantly, once food is contaminated by L. monocytogenes EGDe, contamination proceeds independently of biofilm development and the initial level of contamination when food is stored at 4°C, even if contamination with L. monocytogenes EGDe was initially undetectable before storage.

  2. First Trimester Listeria monocytogenes Septicemia

    NARCIS (Netherlands)

    Goddijn, M.; Schipper, H. G.; Spanjaard, L.; Wolf, H.

    1997-01-01

    Background: Little is known about fetal outcome after Listeria monocytogenes septicemia in the first trimester of pregnancy.Case: A primigravida with L. monocytogenes septicemia at 9 weeks gestation was treated with amoxicillin. At 40 weeks gestation a healthy female infant was born.Conclusion: This

  3. Growth of Listeria monocytogenes in Camembert and other soft cheeses at refrigeration temperatures.

    Science.gov (United States)

    Back, J P; Langford, S A; Kroll, R G

    1993-08-01

    Listeria monocytogenes survived and, under most conditions, multiplied when inoculated directly into the cheese milk of laboratory made Camembert cheeses. The rate and extent of growth was reduced at lower storage temperatures. Significantly higher rates of growth occurred at the surface compared with the centre of the cheeses, and these were probably associated with increased pH and proteolysis at the cheese surface due to the mould ripening process. Similar results were obtained with Camenbert cheeses surface inoculated after manufacture. There was also temperature-dependent growth of List. monocytogenes on a range of inoculated commercially manufactured soft cheeses. Significant growth occurred in Cambazola, French and English Brie, blue and white Lymeswold, French Camembert and Brie with garlic. Little if any growth occurred in blue and white Stilton, Mycella, Chaume and full fat soft cheese with garlic and herbs at the temperatures examined.

  4. Listeria monocytogenes Growth Kinetics in Milkshakes Made from Naturally and Artificially Contaminated Ice Cream

    Directory of Open Access Journals (Sweden)

    Joelle K. Salazar

    2018-01-01

    Full Text Available This study assessed the growth of Listeria monocytogenes in milkshakes made using the process-contaminated ice cream associated with a listeriosis outbreak in comparison to milkshakes made with artificially contaminated ice cream. For all temperatures, growth kinetics including growth rates, lag phases, maximum populations, and population increases were determined for the naturally and artificially derived contaminants at 5, 10, 15, and 25°C storage for 144 h. The artificially inoculated L. monocytogenes presented lower growth rates and shorter lag phases than the naturally contaminated populations at all temperatures except for 5°C, where the reverse was observed. At 25°C, lag phases of the naturally and artificially contaminated L. monocytogenes were 11.6 and 7.8 h, respectively. The highest increase in population was observed for the artificially inoculated pathogen at 15°C after 96 h (6.16 log CFU/mL of storage. Growth models for both contamination states in milkshakes were determined. In addition, this study evaluated the antimicrobial effectiveness of flavoring agents, including strawberry, chocolate and mint, on the growth of the pathogen in milkshakes during 10°C storage. All flavor additions resulted in decreased growth rates of L. monocytogenes for both contamination states. The addition of chocolate and mint flavoring also resulted in significantly longer lag phases for both contamination states. This study provides insight into the differences in growth between naturally and artificially contaminated L. monocytogenes in a food product.

  5. Listeria monocytogenes Growth Kinetics in Milkshakes Made from Naturally and Artificially Contaminated Ice Cream.

    Science.gov (United States)

    Salazar, Joelle K; Bathija, Vriddi M; Carstens, Christina K; Narula, Sartaj S; Shazer, Arlette; Stewart, Diana; Tortorello, Mary Lou

    2018-01-01

    This study assessed the growth of Listeria monocytogenes in milkshakes made using the process-contaminated ice cream associated with a listeriosis outbreak in comparison to milkshakes made with artificially contaminated ice cream. For all temperatures, growth kinetics including growth rates, lag phases, maximum populations, and population increases were determined for the naturally and artificially derived contaminants at 5, 10, 15, and 25°C storage for 144 h. The artificially inoculated L. monocytogenes presented lower growth rates and shorter lag phases than the naturally contaminated populations at all temperatures except for 5°C, where the reverse was observed. At 25°C, lag phases of the naturally and artificially contaminated L. monocytogenes were 11.6 and 7.8 h, respectively. The highest increase in population was observed for the artificially inoculated pathogen at 15°C after 96 h (6.16 log CFU/mL) of storage. Growth models for both contamination states in milkshakes were determined. In addition, this study evaluated the antimicrobial effectiveness of flavoring agents, including strawberry, chocolate and mint, on the growth of the pathogen in milkshakes during 10°C storage. All flavor additions resulted in decreased growth rates of L. monocytogenes for both contamination states. The addition of chocolate and mint flavoring also resulted in significantly longer lag phases for both contamination states. This study provides insight into the differences in growth between naturally and artificially contaminated L. monocytogenes in a food product.

  6. Thermal Inactivation of Listeria monocytogenes and Salmonella during Water and Steam Blanching of Vegetables.

    Science.gov (United States)

    Ceylan, Erdogan; McMahon, Wendy; Garren, Donna M

    2017-09-01

    Thermal inactivation of Listeria monocytogenes and Salmonella was evaluated on peas, spinach, broccoli, potatoes, and carrots that were treated with hot water and steam. One gram-positive bacterium, L. monocytogenes, and one gram-negative bacterium, Salmonella, were selected as pertinent human pathogens for evaluation. Samples were inoculated with a composite of five strains each of L. monocytogenes and Salmonella to achieve approximately 10 8 to 10 9 CFU/g. Inoculated samples were treated with hot water at 85 and 87.8°C and with steam at 85 and 96.7°C for up to 3.5 min. A greater than 5-log reduction of L. monocytogenes and Salmonella was achieved on all products within 0.5 min by hot water blanching at 85 and 87.8°C. Steam blanching at 85°C reduced Salmonella populations by greater than 5 log on spinach and peas within 2 min and on carrots and broccoli within 3.5 min. Populations of Salmonella were reduced by more than 5 log within 1 min on carrot, spinach, and broccoli and within 2 min on peas by steam blanching at 96.7°C. Steam blanching at 85°C reduced L. monocytogenes populations by more than 5 log on carrots and spinach within 2 min and on broccoli and peas within 3.5 min. L. monocytogenes populations were reduced more than 5 log within 1 min on carrot, spinach, peas and broccoli by steam blanching at 96.7°C. Longer treatment times and higher temperatures were required for steam-blanched samples than for samples blanched with hot water. Results suggest that hot water and steam blanching practices commonly used by the frozen vegetable industry will achieve the desired 5-log lethality of L. monocytogenes and Salmonella and will enhance microbiological safety prior to freezing.

  7. Antimicrobial treatments to control Listeria monocytogenes in queso fresco.

    Science.gov (United States)

    Lourenço, António; Kamnetz, Mary B; Gadotti, Camila; Diez-Gonzalez, Francisco

    2017-06-01

    Queso fresco, is a Hispanic non-fermented cheese highly susceptible to contamination with L. monocytogenes. This research was aimed to determine the effect of GRAS antimicrobial ingredients to control L. monocytogenes. Antimicrobials included caprylic acid (CA), Nisaplin ® (N, 2.5% nisin), a mixture of sodium lactate and sodium diacetate (SL/SD), Lactococcus lactis sbp. lactis DPC 3147, monolaurin, and lactic acid (LA). Batches of queso fresco curds were inoculated with 10 4  CFU/g and stored at 4 °C for three weeks. During storage the count of L. monocytogenes reached 7 to 8 Log CFU/g in control samples. Most individual antimicrobial treatments resulted in less than 1 Log CFU/g reductions in final counts, with the exception of N (0.5 g/kg) and CA (2.9 g/kg) that caused more than 3 and 5 Log CFU/g differences with controls, respectively. Mixtures of ingredients were more effective in inhibiting L. monocytogenes growth, and treatments with N and CA consistently delivered 6 Log CFU/g less counts than controls. Supplementation of 12 g/kg LA to treatments with SL/SD (3%/0.22%) caused differences of more than 4 Log CFU/g in final Listeria populations. Samples treated with the binary mixtures of N and CA (0.5 and 0.7 g/kg, respectively) were evaluated in a consumer panel (n = 67). Panelists slightly preferred control and commercial over treated samples, but all samples were in average rated between "slightly liking" and "moderately liking." These experiments indicated that combined use of antimicrobial ingredients may be an effective way to control the population of Listeria monocytogenes in queso fresco. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Inhibition of Listeria monocytogenes by Lactobacillus bavaricus MN in beef systems at refrigeration temperatures.

    OpenAIRE

    Winkowski, K; Crandall, A D; Montville, T J

    1993-01-01

    The ability of Lactobacillus bavaricus, a meat isolate, to inhibit the growth of three Listeria monocytogenes strains was examined in three beef systems: beef cubes, beef cubes in gravy, and beef cubes in gravy containing glucose. The beef was minimally heat treated, inoculated with L. bavaricus at 10(5) or 10(3) CFU/g and L. monocytogenes at 10(2) CFU/g, vacuum sealed, and stored at 4 or 10 degrees C. The meat samples were monitored for microbial growth, pH, and bacteriocin production. The p...

  9. Diferenciação entre Listeria monocytogenes e Erysipelothrix rhusiopathiae com o clorêto de Trifeniltetrazólio

    Directory of Open Access Journals (Sweden)

    Vinicius Moreira Dias

    1958-12-01

    Full Text Available Experiências foram realizadas com bactérias dos gêneros Listeria e Erysipelothrix, em meios líquido e sólido, utilizando o clorêto de 2, 3, 5 - trifeniltetrazólio. A atividade enzimática redutora das listérias para o TTC foi diferente da do E. rhusiopathiae, principalmente em meio líquido e nas horas iniciais de observação. Preparações feitas para microscopia ótica e electrônica dos germes tratados com TTC revelaram a presença de granulações polares, bipolares e centrais dentro do corpo das listérias. A evidenciação de granulações coradas de formazana, intracelulares nas listérias, confirma estudos anteriores quanto à possibilidade da existência de mitocôndrias nas bactérias.Based on a similarity of cultural and biochemical properties, WILSON and MILLES (6 compared the microorganisms of listeriosis with those of swine erysipelas including them in the genus Erysipelothrix with the species E. monocytogenes and E. rhusiopathiae. However, BARBER (1 and JULIANELLE (4, in a comparative study of both microorganisms, do not admit that possibility. Observing the morphological and citochemical characteristics of L. monocytogenes (N.º 7 973, 5 348, 5 105, 5 214, of the Seeliger collection and E. ehusiopathiae cultures (N.º 1, 7, 11, 27, 37, of the WIX collection, both in phase "S", we were able to verify their comparative behavior when in contact with 2-3-5-triphenyltetrazolium chloride (TTC, "Synthetical Laboratories, Chicago, U.S.A". 1. To 1,0 ml of cultures of both microorganisms grown in plain broth plus 5% horse serum for 24 hours at 37ºC, 0.1 ml of sterilized 1% aqueous solution of TTC was added. The tubes were left at room temperature (± 25ºC or in the incubator (37ºC. In the tubes with L. monocytogenes immediately appeared a red coloration (fig. 1 characteristic of formazan production, that became gradually more pronounced, from bottom to top (figs. 2, 3, 4, 5; at the and of 24 hours the color was intense the tube

  10. Validation of the ANSR(®) Listeria monocytogenes Method for Detection of Listeria monocytogenes in Selected Food and Environmental Samples.

    Science.gov (United States)

    Caballero, Oscar; Alles, Susan; Le, Quynh-Nhi; Gray, R Lucas; Hosking, Edan; Pinkava, Lisa; Norton, Paul; Tolan, Jerry; Mozola, Mark; Rice, Jennifer; Chen, Yi; Ryser, Elliot; Odumeru, Joseph

    2016-01-01

    Work was conducted to validate performance of the ANSR(®) for Listeria monocytogenes method in selected food and environmental matrixes. This DNA-based assay involves amplification of nucleic acid via an isothermal reaction based on nicking enzyme amplification technology. Following single-step sample enrichment for 16-24 h for most matrixes, the assay is completed in 40 min using only simple instrumentation. When 50 distinct strains of L. monocytogenes were tested for inclusivity, 48 produced positive results, the exceptions being two strains confirmed by PCR to lack the assay target gene. Forty-seven nontarget strains (30 species), including multiple non-monocytogenes Listeria species as well as non-Listeria, Gram-positive bacteria, were tested, and all generated negative ANSR assay results. Performance of the ANSR method was compared with that of the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure for detection of L. monocytogenes in hot dogs, pasteurized liquid egg, and sponge samples taken from an inoculated stainless steel surface. In addition, ANSR performance was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method for detection of L. monocytogenes in Mexican-style cheese, cantaloupe, sprout irrigation water, and guacamole. With the single exception of pasteurized liquid egg at 16 h, ANSR method performance as quantified by the number of positives obtained was not statistically different from that of the reference methods. Robustness trials demonstrated that deliberate introduction of small deviations to the normal assay parameters did not affect ANSR method performance. Results of accelerated stability testing conducted using two manufactured lots of reagents predicts stability at the specified storage temperature of 4°C of more than 1 year.

  11. 16 CFR 4.5 - Fees.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Fees. 4.5 Section 4.5 Commercial Practices... same fees and mileage as are paid witnesses in the courts of the United States. (b) Presiding officers... in the courts of the United States. (c) Responsibility. The fees and mileage referred to in this...

  12. Thermal resistance of Listeria monocytogenes in sausage meat.

    Science.gov (United States)

    Farber, J M; Hughes, A; Holley, R; Brown, B

    1989-01-01

    The heat resistance of a mixture of 10 different strains of Listeria monocytogenes inoculated into ground meat and ground meat plus cure was examined. D-values for ground meat ranged from 1.01 min at 62 degrees C to 13.18 min at 56 degrees C. The D-values obtained for ground meat plus cure were approximately 5-8 fold times higher than those for ground meat alone. These results imply that rare meats and possibly some cooked fermented meats may not be heated adequately to inactivate Listeria.

  13. Predicted and observed growth of Listeria monocytogenes in seafood challenge tests and in naturally contaminated cold smoked salmon

    DEFF Research Database (Denmark)

    Dalgaard, Paw; Jørgensen, Lasse Vigel

    1998-01-01

    with various types of seafoods. Storage trials clearly showed the growth of L. monocytogenes in naturally contaminated cold-smoked salmon to be markedly slower than growth in inoculated challenge tests. Consequently, all four models substantially overestimated growth in the naturally contaminated products...

  14. N-(4,5-Diazafluoren-9-ylideneaniline

    Directory of Open Access Journals (Sweden)

    Hui Cang

    2008-07-01

    Full Text Available In the molecule of the title compound, C17H11N3, the 4,5-diazafluorenylidene unit is nearly planar and is oriented with respect to the phenyl ring at a dihedral angle of 75.75 (3°. In the crystal structure, the molecules are aligned in the [100] direction in such a way that neighbouring 4,5-diazafluorenylidene planes face each other in an antiparallel fashion.

  15. Inhibition of Listeria monocytogenes by piscicolin 126 in milk and Camembert cheese manufactured with a thermophilic starter.

    Science.gov (United States)

    Wan, J; Harmark, K; Davidson, B E; Hillier, A J; Gordon, J B; Wilcock, A; Hickey, M W; Coventry, M J

    1997-03-01

    The effect of bacteriocin, piscicolin 126, on the growth of Listeria monocytogenes and cheese starter bacteria was investigated in milk and in Camembert cheese manufactured from milk challenged with 10(2) cfu ml(-1) L. monocytogenes. In milk incubated at 30 degrees C, piscicolin 126 added in the range of 512-2,048 AU ml(-1) effectively inhibited growth of L. monocytogenes for more than 20 d when challenged with approximately 10(2) cfu ml(-1) L. monocytogenes. At higher challenge levels (10(4) and 10(6) cfu ml(-1)), piscicolin 126 reduced the viable count of L. monocytogenes by 4-5 log units immediately after addition of the bacteriocin; however, growth of Listeria occurred within 24 h. The minimum inhibitory concentration (MIC) of piscicolin 126 against lactic acid cheese starter bacteria was generally greater than 204,800 AU ml(-1) , and the viable count and acid production of these starter cultures in milk were not affected by the addition of 2,048 AU ml(-1) piscicolin 126. Camembert cheeses made from milk challenged with L. monocytogenes and with added piscicolin 126 showed a viable count of L. monocytogenes 3-4 log units lower than those without piscicolin 126. Inactivation of piscicolin 126 by proteolytic enzymes from cheese starter bacteria and mould together with the emergence of piscicolin 126-resistant isolates was responsible for the recovery of L. monocytogenes in the cheeses during ripening.

  16. Changes in gene expression during adaptation of Listeria monocytogenes to the soil environment.

    Science.gov (United States)

    Piveteau, Pascal; Depret, Géraldine; Pivato, Barbara; Garmyn, Dominique; Hartmann, Alain

    2011-01-01

    Listeria monocytogenes is a ubiquitous opportunistic pathogen responsible for listeriosis. In order to study the processes underlying its ability to adapt to the soil environment, whole-genome arrays were used to analyse transcriptome modifications 15 minutes, 30 minutes and 18 h after inoculation of L. monocytogenes EGD-e in soil extracts. Growth was observed within the first day of incubation and large numbers were still detected in soil extract and soil microcosms one year after the start of the experiment. Major transcriptional reprofiling was observed. Nutrient acquisition mechanisms (phosphoenolpyruvate-dependent phosphotransferase systems and ABC transporters) and enzymes involved in catabolism of specific carbohydrates (β-glucosidases; chitinases) were prevalent. This is consistent with the overrepresentation of the CodY regulon that suggests that in a nutrient depleted environment, L. monocytogenes recruits its extensive repertoire of transporters to acquire a range of substrates for energy production.

  17. Antibacterial activity of bacteriocin-like substance P34 on Listeria monocytogenes in chicken sausage

    Directory of Open Access Journals (Sweden)

    Voltaire Sant'Anna

    2013-12-01

    Full Text Available The antimicrobial activity of the bacteriocin-like substance (BLS P34 against Listeria monocytogenes was investigated in chicken sausage. The BLS was applied to chicken sausages (256 AU g-1 previously inoculated with a suspension of 10² cfu g-1 of L. monocytogenes. BLS P34 inhibited the indicator microorganism in situ in all incubation times for up to 10 days at 5 °C. The effectiveness of BLS P34 was increased when it was added in combination with nisin. The bacteriocin was also tested in natural eatable natural bovine wrapping (salty semi-dried tripe against the same indicator microorganism, also showing inhibitory capability in vitro. BLS P34 showed potential to control L. monocytogenes in refrigerated meat products.

  18. Essential oils of thyme and Rosemary in the control of Listeria monocytogenes in raw beef

    Directory of Open Access Journals (Sweden)

    Maíra Maciel Mattos de Oliveira

    2013-12-01

    Full Text Available This study was developed in order to evaluate two alternatives for the control of Listeria monocytogenes in raw bovine meat pieces, both based on the use of Thymus vulgaris and Rosmarinus officinalis essential oils (EOs. The antilisterial activity of different concentrations of the EOs was tested in vitro using agar dilution and disk volatilization techniques. In addition, L. monocytogenes was inoculated in meat pieces, which were submerged in edible gelatin coatings containing 2% (v/v EOs or submitted to the vapor of EOs (0.74 μL.cm-3. L. monocytogenes was quantified after one, 48 and 96 hours of storage (7 °C. In the in vitro tests, the EO of T. vulgaris presented higher activity. The two options used (edible gelatin coating and vapor activity, in spite of exercising effects with differentiated behaviors, presented antibacterial activity against L. monocytogenes inoculated in raw bovine meat (p < 0.05. Greatest antibacterial activity were obtained in the experiment that used edible coatings containing EOs, at 48 hours of storage reductions in bacterial counts between 1.09 and 1.25 Log CFU.g-1 were obtained. In the vapor effect experiment, the EO of T. vulgaris caused the highest reduction in the population of bacteria inoculated in raw bovine meat (p < 0.05, 0.40 Log CFU.g-1 at 96 hours of storage. This study supplied important information regarding new and promising natural alternatives, based on the concept of active packaging, for the control of L. monocytogenes in the meat industry.

  19. Fødevarebetinget listeria monocytogenes endokarditis

    DEFF Research Database (Denmark)

    Frydland, Martin; Bundgaard, Henning; Moser, Claus

    2014-01-01

    Infection with Listeria monocytogenes is rare and mainly seen in immunosuppressed patients. Infection with L. monocytogenes has a mortality rate of 30%. We present a case report of L. monocytogenes bacteraemia and endocarditis in a 70-year-old man with several co-morbidities and following four...... major surgical procedures. This illustrates the findings and characteristics in one of the 16 patients who died in 2013 and 2014 this summer due to sausage-related L. monocytogenes infection....

  20. A Dual Microscopy-Based Assay To Assess Listeria monocytogenes Cellular Entry and Vacuolar Escape.

    Science.gov (United States)

    Quereda, Juan J; Pizarro-Cerdá, Javier; Balestrino, Damien; Bobard, Alexandre; Danckaert, Anne; Aulner, Nathalie; Shorte, Spencer; Enninga, Jost; Cossart, Pascale

    2016-01-01

    Listeria monocytogenes is a Gram-positive bacterium and a facultative intracellular pathogen that invades mammalian cells, disrupts its internalization vacuole, and proliferates in the host cell cytoplasm. Here, we describe a novel image-based microscopy assay that allows discrimination between cellular entry and vacuolar escape, enabling high-content screening to identify factors specifically involved in these two steps. We first generated L. monocytogenes and Listeria innocua strains expressing a β-lactamase covalently attached to the bacterial cell wall. These strains were then incubated with HeLa cells containing the Förster resonance energy transfer (FRET) probe CCF4 in their cytoplasm. The CCF4 probe was cleaved by the bacterial surface β-lactamase only in cells inoculated with L. monocytogenes but not those inoculated with L. innocua, thereby demonstrating bacterial access to the host cytoplasm. Subsequently, we performed differential immunofluorescence staining to distinguish extracellular versus total bacterial populations in samples that were also analyzed by the FRET-based assay. With this two-step analysis, bacterial entry can be distinguished from vacuolar rupture in a single experiment. Our novel approach represents a powerful tool for identifying factors that determine the intracellular niche of L. monocytogenes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. [Design of SCM inoculation device].

    Science.gov (United States)

    Qian, Mingli; Xie, Haiyuan

    2014-01-01

    The first step of bacilli culture is inoculation bacteria on culture medium. Designing a device to increase efficiency of inoculation is significative. The new device is controlled by SCM. The stepper motor can drive the culture medium rotating, accelerating, decelerating, overturn and suspending. The device is high practicability and efficient, let inoculation easy for operator.

  2. Efecto de tiempo y temperatura de cocción en chorizo inoculados artificialmente con Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Ana K. Carrascal-Camacho

    2009-12-01

    Full Text Available Effect of cooking time and temperature on sausages artificially inoculated with Listeria monocytogenes. Objective. To find whetherthe cooking times traditionally used by consumers are enough to inactivate Listeria monocytogenes artificially inoculated into sausages.Materials and methods. A survey asking about sausage cooking habits was completed with 50 housewives. We analyzed 60 samples ofsausages previously inoculated with 103 CFU g-1 from a pool of 5 strains of L. monocytogenes, then the cooking procedures described inthe survey were applied to the samples, and counting was done immediately after. Additionally, a complementary test was carried out byinoculating 20 samples of sausages with 103 CFU g-1 and exposing them to 72 oC and 73 oC for 30 seg. Results. The survey showed that15 minute boiling and 5 minute frying are the most frequent ways of preparing sausages by consumers. We established that the time andcooking conditions used in our assay had a statistically significant effect (p: 0.016 on the inoculated samples. In the complementary assay,statistical data (p: 0.0001 indicated that internal temperatures of 73 oC are enough to inactivate the pathogen at an industrial scale.Conclusion. Cooking by 15 minute boiling and 5 minute frying are enough to inactive concentrations of 103 g-1 of Listeria monocytogenesartificially inoculated into sausages.

  3. Listeria monocytogenes Growth Kinetics in Milkshakes Made from Naturally and Artificially Contaminated Ice Cream

    OpenAIRE

    Salazar, Joelle K.; Bathija, Vriddi M.; Carstens, Christina K.; Narula, Sartaj S.; Shazer, Arlette; Stewart, Diana; Tortorello, Mary Lou

    2018-01-01

    This study assessed the growth of Listeria monocytogenes in milkshakes made using the process-contaminated ice cream associated with a listeriosis outbreak in comparison to milkshakes made with artificially contaminated ice cream. For all temperatures, growth kinetics including growth rates, lag phases, maximum populations, and population increases were determined for the naturally and artificially derived contaminants at 5, 10, 15, and 25°C storage for 144 h. The artificially inoculated L. m...

  4. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes

    International Nuclear Information System (INIS)

    Todoriki, Setsuko; Bari, Latiful; Kitta, Kazumi; Ohba, Mika; Ito, Yasuhiro; Tsujimoto, Yuka; Kanamori, Norihito; Yano, Erika; Moriyama, Tatsuya; Kawamura, Yukio; Kawamoto, Shinichi

    2009-01-01

    The presence of Listeria monocytogenes in fresh produce is a growing concern because of the possibility of food-borne illness. Ionizing radiation is an effective non-thermal means of eliminating pathogenic bacteria in fresh produce; however, the effect of ionizing irradiation on the allergenic properties of the host commodities remains unknown. This study aimed (i) to determine the effective dose of gamma-irradiation in eliminating L. monocytogenes on whole cherry tomatoes and (ii) to evaluate the effect of gamma-irradiation on the allergenic properties of tomato proteins. Cherry tomatoes that were inoculated with a mixture of five L. monocytogenes strains were treated with gamma-rays from a 60 Co source. A 1.25 kGy dose of gamma-irradiation was found to be sufficient to eliminate L. monocytogenes on whole cherry tomatoes. The immunoblot profile of serum samples obtained from two patients with tomato allergy revealed that gamma-irradiation did not affect the allergenicity of tomato proteins for up to 7 days after irradiation when the tomatoes were stored at 20 deg. C. Additionally, the m-RNA levels of β-fructofuranosidase, polygalacturonase, pectin esterase, and superoxide dismutase, the main allergenic proteins in tomato, were not affected by the applied irradiation dose. Thus, this study demonstrated that a 1.25 kGy dose of gamma-irradiation effectively eliminates L. monocytogenes on cherry tomatoes without affecting the expression of allergenic proteins in the fruits.

  5. Gamma irradiation as a means to eliminate Listeria monocytogenes from frozen chicken meat

    International Nuclear Information System (INIS)

    Kamat, A.S.; Nair, M.P.

    1995-01-01

    Cells of Listeria monocytogenes ATCC 35152 were sensitive to gamma irradiation in phosphate buffer, pH 7.00 (D 10 , dose required for 10% survival—0.15 kGy) at 0–5°C. The cells showed higher radiation survival when irradiated under frozen condition, with a D 10 of 0.3 kGy. The protection offered by shrimp/chicken/kheema homogenates (100 g litre−1) was evidenced by even higher D 10 values (0.5 kGy) at both 0–5°C and cryogenic temperature. Boneless chicken meat samples were artificially inoculated with L monocytogenes ATCC 35152 cells at low (5 × 10 3 ) colony-forming unit (cfu) g −1 and high (5 × 10 6 cfu g −1 ) concentrations and irradiated at 1, 3, 4, 6 kGy doses under cryogenic conditions. The efficacy of the radiation process was evaluated by detecting L monocytogenes during storage at 2–4°C in the irradiated samples. These studies, when repeated with three other serotypes of L monocytogenes, clearly suggested the need for a dose of 3 kGy for elimination of 10 3 cfu cells of L monocytogenes g −1 from air-packed frozen chicken meat. (author)

  6. Antimicrobial activity of chitosan coatings and films against Listeria monocytogenes on black radish.

    Science.gov (United States)

    Jovanović, Gordana D; Klaus, Anita S; Nikšić, Miomir P

    2016-01-01

    The antibacterial activity of chitosan coatings prepared with acetic or lactic acid, as well as of composite chitosan-gelatin films prepared with essential oils, was evaluated in fresh shredded black radish samples inoculated with Listeria monocytogenes ATCC 19115 and L. monocytogenes ATCC 19112 during seven days of storage at 4°C. The chitosan coating prepared with acetic acid showed the most effective antibacterial activity. All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of L. monocytogenes on black radish, although a higher inhibition of pathogens was achieved at higher concentrations of chitosan. The antimicrobial effect of chitosan films was even more pronounced with the addition of essential oils. Chitosan-gelatin films with thyme essential oils showed the most effective antimicrobial activity. A reduction of 2.4log10CFU/g for L. monocytogenes ATCC 19115 and 2.1log10CFU/g for L. monocytogenes ATCC 19112 was achieved in the presence of 1% chitosan film containing 0.2% of thyme essential oil after 24h of storage. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Efficacy of household washing treatments for the control of Listeria monocytogenes on salad vegetables.

    Science.gov (United States)

    Nastou, Aikaterini; Rhoades, Jonathan; Smirniotis, Petros; Makri, Ioanna; Kontominas, Michael; Likotrafiti, Eleni

    2012-10-15

    The efficacy of household decontamination methods at reducing Listeria monocytogenes on fresh lettuce (Lactuca sativa), cucumber (Cucumis sativus) and parsley (Petroselinum sativum) was studied. Inoculated vegetable pieces were immersed in washing solutions and surviving L. monocytogenes enumerated. Parameters investigated were storage temperature prior to washing, dipping water temperature, agitation, acetic acid concentration and immersion time. The results indicated that the storage temperature significantly affects the efficacy of dipping vegetables in water for the control of L. monocytogenes, as the reduction in count was greatest when products had been stored at cooler temperatures. Decontamination with acetic acid (up to 2.0% v/v) was shown to have some effect in most cases, but the highest observed decrease in count was 2.6 log cfu/g. Experiments investigating the effect of exposure time to acetic acid (0.5% and 1.0% v/v, up to 30 min immersion) indicated that immersing the vegetables for more than 10 min is of minimal benefit. The most significant factor affecting washing and decontamination efficacy was the vegetable itself: L. monocytogenes colonizing cucumber epidermis was far more resistant to removal by washing and to acid treatment than that on the leafy vegetables, and L. monocytogenes on parsley was the most susceptible. This shows that published decontamination experiments (often performed with lettuce) cannot necessarily be extrapolated to other vegetables. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes

    Science.gov (United States)

    Todoriki, Setsuko; Bari, Latiful; Kitta, Kazumi; Ohba, Mika; Ito, Yasuhiro; Tsujimoto, Yuka; Kanamori, Norihito; Yano, Erika; Moriyama, Tatsuya; Kawamura, Yukio; Kawamoto, Shinichi

    2009-07-01

    The presence of Listeria monocytogenes in fresh produce is a growing concern because of the possibility of food-borne illness. Ionizing radiation is an effective non-thermal means of eliminating pathogenic bacteria in fresh produce; however, the effect of ionizing irradiation on the allergenic properties of the host commodities remains unknown. This study aimed (i) to determine the effective dose of gamma-irradiation in eliminating L. monocytogenes on whole cherry tomatoes and (ii) to evaluate the effect of gamma-irradiation on the allergenic properties of tomato proteins. Cherry tomatoes that were inoculated with a mixture of five L. monocytogenes strains were treated with gamma-rays from a 60Co source. A 1.25 kGy dose of gamma-irradiation was found to be sufficient to eliminate L. monocytogenes on whole cherry tomatoes. The immunoblot profile of serum samples obtained from two patients with tomato allergy revealed that gamma-irradiation did not affect the allergenicity of tomato proteins for up to 7 days after irradiation when the tomatoes were stored at 20 °C. Additionally, the m-RNA levels of β-fructofuranosidase, polygalacturonase, pectin esterase, and superoxide dismutase, the main allergenic proteins in tomato, were not affected by the applied irradiation dose. Thus, this study demonstrated that a 1.25 kGy dose of gamma-irradiation effectively eliminates L. monocytogenes on cherry tomatoes without affecting the expression of allergenic proteins in the fruits.

  9. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes

    Energy Technology Data Exchange (ETDEWEB)

    Todoriki, Setsuko [National Food Research Institute, Tsukuba, Ibaraki 305-8642 (Japan)], E-mail: setsuko@affrc.go.jp; Bari, Latiful; Kitta, Kazumi; Ohba, Mika; Ito, Yasuhiro; Tsujimoto, Yuka [National Food Research Institute, Tsukuba, Ibaraki 305-8642 (Japan); Kanamori, Norihito [Japan International Research Center for Agricultural Science, Tsukuba, Ibaraki 305-8686 (Japan); Yano, Erika; Moriyama, Tatsuya; Kawamura, Yukio [School of Agriculture, Kinki University, Nara-city, Nara 631-8505 (Japan); Kawamoto, Shinichi [National Food Research Institute, Tsukuba, Ibaraki 305-8642 (Japan)

    2009-07-15

    The presence of Listeria monocytogenes in fresh produce is a growing concern because of the possibility of food-borne illness. Ionizing radiation is an effective non-thermal means of eliminating pathogenic bacteria in fresh produce; however, the effect of ionizing irradiation on the allergenic properties of the host commodities remains unknown. This study aimed (i) to determine the effective dose of gamma-irradiation in eliminating L. monocytogenes on whole cherry tomatoes and (ii) to evaluate the effect of gamma-irradiation on the allergenic properties of tomato proteins. Cherry tomatoes that were inoculated with a mixture of five L. monocytogenes strains were treated with gamma-rays from a {sup 60}Co source. A 1.25 kGy dose of gamma-irradiation was found to be sufficient to eliminate L. monocytogenes on whole cherry tomatoes. The immunoblot profile of serum samples obtained from two patients with tomato allergy revealed that gamma-irradiation did not affect the allergenicity of tomato proteins for up to 7 days after irradiation when the tomatoes were stored at 20 deg. C. Additionally, the m-RNA levels of {beta}-fructofuranosidase, polygalacturonase, pectin esterase, and superoxide dismutase, the main allergenic proteins in tomato, were not affected by the applied irradiation dose. Thus, this study demonstrated that a 1.25 kGy dose of gamma-irradiation effectively eliminates L. monocytogenes on cherry tomatoes without affecting the expression of allergenic proteins in the fruits.

  10. Assessment of Listeria monocytogenes virulence in the Galleria mellonella insect larvae model.

    Science.gov (United States)

    Rakic Martinez, Mira; Wiedmann, Martin; Ferguson, Martine; Datta, Atin R

    2017-01-01

    Several animal models have been used to understand the molecular basis of the pathogenicity, infectious dose and strain to strain variation of Listeria monocytogenes. The greater wax worm Galleria mellonella, as an alternative model, provides some useful advantages not available with other models and has already been described as suitable for the virulence assessment of various pathogens including L. monocytogenes. The objectives of this study are: 1) confirming the usefulness of this model with a wide panel of Listeria spp. including non-pathogenic L. innocua, L. seeligeri, L. welshimeri and animal pathogen L. ivanovii; 2) assessment of virulence of several isogenic in-frame deletion mutants in virulence and stress related genes of L. monocytogenes and 3) virulence assessment of paired food and clinical isolates of L. monocytogenes from 14 major listeriosis outbreaks occurred worldwide between 1980 and 2015. Larvae injected with different concentrations of Listeria were incubated at 37°C and monitored over seven days for time needed to kill 50% of larvae (LT50) and to determine change of bacterial population in G. mellonella, 2 and 24 hours post-inoculation. Non-pathogenic members of Listeria and L. ivanovii showed significantly (P monocytogenes strains. Isogenic mutants of L. monocytogenes with the deletions in prfA, plcA, hly, actA and virR genes, also showed significantly (P monocytogenes strains related to non-invasive (gastroenteritis) outbreaks of listeriosis showed significantly (P < 0.05) lower virulence than isolates of the same serotype obtained from outbreaks with invasive symptoms. The difference, however, was dose and strain- dependent. No significant differences in virulence were observed among the serotype tested in this study.

  11. Listeria monocytogenes endophthalmitis following keratoconjunctivitis.

    Science.gov (United States)

    Shoughy, Samir S; Tabbara, Khalid F

    2014-01-01

    Endophthalmitis due to endogenous or exogenous bacteria is a rare infection of the eye. We report a case of endophthalmitis following Listeria monocytogenes keratoconjunctivitis in a 27-year-old healthy white male presenting with hand motion visual acuity, right eye mucopurulent conjunctivitis, elevated intraocular pressure, and pigmented hypopyon 6 months post-keratectomy. The conjunctivitis was unresponsive to a 5-day course of topical tobramycin eye drops, and the patient developed keratitis with pain that progressed to endophthalmitis after 21 days. Diagnostic B-scan revealed vitreous exudates. Intraocular fluid specimen showed Gram-positive organisms and the aqueous culture grew penicillin-/aminoglycoside-sensitive L. monocytogenes. The patient was given intravitreal and systemic vancomycin and ceftazidime. The eye was unresponsive to intravenous penicillin and gentamicin; the anterior chamber progressively flattened and developed phthisis bulbi. L. monocytogenes keratoconjunctivitis may lead to bacterial endophthalmitis. Prompt culture and early antibiotic therapy are recommended.

  12. Inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree by high hydrostatic pressure with/without added ascorbic acid.

    Science.gov (United States)

    Mukhopadhyay, Sudarsan; Sokorai, Kimberly; Ukuku, Dike; Fan, Xuetong; Juneja, Vijay; Sites, Joseph; Cassidy, Jennifer

    2016-10-17

    The objective of this research was to evaluate and develop a method for inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree (CP) by high hydrostatic pressure (HHP). Cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. Freshly prepared CP with or without 0.1% ascorbic acid (AA) was inoculated with a bacterial cocktail composed of a three serotype mixture of S. enterica (S. Poona, S. Newport H1275 and S. Stanley H0558) and a mixture of three strains of L. monocytogenes (Scott A, 43256 and 51742) to a population of ca. 10(8)CFU/g. Double sealed and double bagged inoculated CP (ca. 5g) were pressure treated at 300, 400 and 500MPa at 8°C and 15°C for 5min. Data indicated increased inactivation of both Salmonella and Listeria spp. with higher pressure. Log reduction for CP at 300MPa, 8°C for 5min was 2.4±0.2 and 1.6±0.5logCFU/g for Salmonella and Listeria, respectively. Survivability of the pathogens was significantly compromised at 400MPa and 8°C, inactivating 4.5±0.3logCFU/g of Salmonella and 3.0±0.4logCFU/g of Listeria spp. Complete inactivation of the pathogens in the puree (log reduction >6.7logCFU/g), with or without AA, was achieved when the pressure was further increased to 500MPa, except that for Listeria containing no AA at 8°C. Listeria presented higher resistance to pressure treatment compared to Salmonella spp. Initial temperatures (8 and 15°C) had no significant influence on Salmonella log reductions. Log reduction of pathogens increased but not significantly with increase of temperature. AA did not show any significant antimicrobial activity. Viable counts were about 0.2-0.4logCFU/g less in presence of 0.1% AA. These data validate that HHP can be used as an effective method for decontamination of cantaloupe puree. Published by Elsevier B.V.

  13. .NET 4.5 parallel extensions

    CERN Document Server

    Freeman, Bryan

    2013-01-01

    This book contains practical recipes on everything you will need to create task-based parallel programs using C#, .NET 4.5, and Visual Studio. The book is packed with illustrated code examples to create scalable programs.This book is intended to help experienced C# developers write applications that leverage the power of modern multicore processors. It provides the necessary knowledge for an experienced C# developer to work with .NET parallelism APIs. Previous experience of writing multithreaded applications is not necessary.

  14. Nisin, rosemary, and ethylenediaminetetraacetic acid affect the growth of Listeria monocytogenes on ready-to-eat turkey ham stored at four degrees Celsius for sixty-three days.

    Science.gov (United States)

    Ruiz, A; Williams, S K; Djeri, N; Hinton, A; Rodrick, G E

    2009-08-01

    The objectives of this study were to determine the anti-Listeria and general antimicrobial properties of nisin, rosemary, and EDTA alone and in combination on Listeria monocytogenes inoculated on ready-to-eat vacuum-packaged diced turkey ham and to ascertain the effects of the treatments on pH and objective color. The turkey hams were cut into 0.5-cm pieces, inoculated with a L. monocytogenes cocktail containing 5 strains of the bacterium, and treated with either no treatment and no inoculum (negative control), inoculum only (positive control), 0.5% nisin, 20 mM EDTA, 1% rosemary, 0.5% nisin + 20 mM EDTA, 0.5% nisin + 1% rosemary, 0.5% nisin + 20 mM EDTA + 1% rosemary, or 20 mM EDTA + 1% rosemary. All samples were vacuum-packaged, stored for 63 d at 4 degrees C +/- 1 degrees C, and analyzed at 1-wk intervals for total aerobes, L. monocytogenes, lactic acid organisms, pH, and objective color. Nisin, nisin with rosemary, nisin with EDTA, and nisin with rosemary and EDTA treatments reduced (P hams treated with nisin. The EDTA and rosemary treatments alone and in combination were ineffective in inhibiting growth of L. monocytogenes. Although none of the treatments completely eliminated L. monocytogenes, the results indicated that ready-to-eat turkey ham can have significantly decreased L. monocytogenes when treated with nisin alone or in combination with rosemary or EDTA, or both.

  15. Listeria monocytogenes endophthalmitis following keratoconjunctivitis

    Directory of Open Access Journals (Sweden)

    Shoughy SS

    2014-01-01

    Full Text Available Samir S Shoughy,1 Khalid F Tabbara1–31The Eye Center and The Eye Foundation for Research in Ophthalmology, Riyadh, Saudi Arabia; 2Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 3The Wilmer Ophthalmological Institute of The Johns Hopkins University School of Medicine, Baltimore, MD, USAAbstract: Endophthalmitis due to endogenous or exogenous bacteria is a rare infection of the eye. We report a case of endophthalmitis following Listeria monocytogenes keratoconjunctivitis in a 27-year-old healthy white male presenting with hand motion visual acuity, right eye mucopurulent conjunctivitis, elevated intraocular pressure, and pigmented hypopyon 6 months post-keratectomy. The conjunctivitis was unresponsive to a 5-day course of topical tobramycin eye drops, and the patient developed keratitis with pain that progressed to endophthalmitis after 21 days. Diagnostic B-scan revealed vitreous exudates. Intraocular fluid specimen showed Gram-positive organisms and the aqueous culture grew penicillin-/aminoglycoside-sensitive L. monocytogenes. The patient was given intravitreal and systemic vancomycin and ceftazidime. The eye was unresponsive to intravenous penicillin and gentamicin; the anterior chamber progressively flattened and developed phthisis bulbi. L. monocytogenes keratoconjunctivitis may lead to bacterial endophthalmitis. Prompt culture and early antibiotic therapy are recommended.Keywords: conjunctivitis, L. monocytogenes, endophthalmitis

  16. Real-time PCR detection of Listeria monocytogenes in infant formula and lettuce following macrophage-based isolation and enrichment.

    Science.gov (United States)

    Day, J B; Basavanna, U

    2015-01-01

    To develop a rapid detection procedure for Listeria monocytogenes in infant formula and lettuce using a macrophage-based enrichment protocol and real-time PCR. A macrophage cell culture system was employed for the isolation and enrichment of L. monocytogenes from infant formula and lettuce for subsequent identification using real-time PCR. Macrophage monolayers were exposed to infant formula and lettuce contaminated with a serial dilution series of L. monocytogenes. As few as approx. 10 CFU ml(-1) or g(-1) of L. monocytogenes were detected in infant formula and lettuce after 16 h postinfection by real-time PCR. Internal positive PCR controls were utilized to eliminate the possibility of false-negative results. Co-inoculation with Listeria innocua did not reduce the L. monocytogenes detection sensitivity. Intracellular L. monocytogenes could also be isolated on Listeria selective media from infected macrophage lysates for subsequent confirmation. The detection method is highly sensitive and specific for L. monocytogenes in infant formula and lettuce and establishes a rapid identification time of 20 and 48 h for presumptive and confirmatory identification, respectively. The method is a promising alternative to many currently used q-PCR detection methods which employ traditional selective media for enrichment of contaminated food samples. Macrophage enrichment of L. monocytogenes eliminates PCR inhibitory food elements and contaminating food microflora which produce cleaner samples that increase the rapidity and sensitivity of detection. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  17. Inhibition of Listeria monocytogenes by propionic acid-based ingredients in cured deli-style Turkey.

    Science.gov (United States)

    Glass, Kathleen A; McDonnell, Lindsey M; Von Tayson, Roxanne; Wanless, Brandon; Badvela, Mani

    2013-12-01

    Listeria monocytogenes growth can be controlled on ready-to-eat meats through the incorporation of antimicrobial ingredients into the formulation or by postlethality kill steps. However, alternate approaches are needed to provide options that reduce sodium content but maintain protection against pathogen growth in meats after slicing. The objective of this study was to determine the inhibition of L. monocytogenes by propionic acid-based ingredients in high-moisture, cured turkey stored at 4 or 7°C. Six formulations of sliced, cured (120 ppm of NaNO2 ), deli-style turkey were tested, including control without antimicrobials, 3.2% lactate-diacetate blend (LD), 0.4% of a liquid propionate-benzoate-containing ingredient, or 0.3, 0.4, and 0.5% of a liquid propionate-containing ingredient. Products were inoculated with 5 log CFU L. monocytogenes per 100-g package (3 log CFU/ml rinsate), vacuum-sealed, and stored at 4 or 7°C for up to 12 weeks; and populations were enumerated by plating on modified Oxford agar. As expected, the control without antimicrobials supported rapid growth, with >2 log average per ml rinsate increase within 4 weeks of storage at 4°C, whereas growth was observed at 6 weeks for the LD treatment. For both replicate trials, all treatments that contained liquid propionate or propionate-benzoate limited L. monocytogenes growth to an increase of 1-log increase) was observed in individual samples for all propionate-containing treatments at weeks 10, 11, and 12. As expected, L. monocytogenes grew more rapidly when products were stored at 7°C, but trends in relative inhibition were similar to those observed at 4°C. These results verify that propionate-based ingredients inhibit growth of L. monocytogenes on sliced, high-moisture, cured turkey and can be considered as an alternative to reduce sodium-based salts while maintaining food safety.

  18. Inoculation Technique for Fungus Cultures

    Science.gov (United States)

    Fusaro, Ramon M.

    1972-01-01

    A plastic straw and wood applicator stick serve as a simple, inexpensive, and disposable inoculation unit for fungal studies. The method gives a uniform and intact inoculum. The technique is especially useful because a large number of agar plates can be inoculated rapidly. Images PMID:5059618

  19. Biocontrole de Listeria monocytogenes por Pediococcus acidilactici em couve minimamente processada Biocontrol of Listeria monocytogenes by Pediococcus acidilactici in fresh-cut kale

    Directory of Open Access Journals (Sweden)

    Wanessa Altimiras Costa

    2009-12-01

    selected as a possible biological control bacterium. The population of L. monocytogenes inoculated in minimally processed kale increased 3.7 and 4.7 logarithmic cycles at 5 and 10 °C, respectively, after 20 days of storage and 4.6 logarithmic cycles at 15 °C after eight days. However, when 10(8 CFU.g-1 of P. acidilactici CCA3 was inoculated into processed product a reduction of L. monocytogenes of 2.3 logarithmic cycles under extreme temperature conditions (15 °C occurred. P. acidilactici CCA3 did not alter the titratable acidity or the kale sensorial characteristics during the shelf life period. These results suggest the potential application of biopreservatives on minimally processed kale that need to be associated with refrigeration and sanitation to assure safety.

  20. Antilisterial properties of marinades during refrigerated storage and microwave oven reheating against post-cooking inoculated chicken breast meat.

    Science.gov (United States)

    Fouladkhah, Aliyar; Geornaras, Ifigenia; Nychas, George-John; Sofos, John N

    2013-02-01

    This study evaluated growth of Listeria monocytogenes inoculated on cooked chicken meat with different marinades and survival of the pathogen as affected by microwave oven reheating. During aerobic storage at 7 °C, on days 0, 1, 2, 4, and 7, samples were reheated by microwave oven (1100 W) for 45 or 90 s and analyzed microbiologically. L. monocytogenes counts on nonmarinated (control) samples increased (P 2.4 to 5.0 (90 s) log CFU/g. With similar trends across different marinates, the high levels of L. monocytogenes survivors found after microwave reheating, especially after storage for more than 2 d, indicate that length of storage and reheating time need to be considered for safe consumption of leftover cooked chicken. © 2013 Institute of Food Technologists®

  1. Combined effect of ultrasound and essential oils to reduce Listeria monocytogenes on fresh produce.

    Science.gov (United States)

    Özcan, Gülçin; Demirel Zorba, Nükhet Nilüfer

    2016-06-01

    Salads prepared from contaminated fresh produce have a high risk of causing food-borne illnesses. Essential oils obtained from plants have antimicrobial activity and may provide a natural approach to reduce the pathogens on fresh produce. Additionally, ultrasound treatments have been shown to reduce the microbial counts on different foods. The objective of this study was to investigate the antimicrobial activities of cinnamon and lemon essential oils in vitro and in food applications. Mixtures of lettuce, parsley and dill were inoculated with Listeria monocytogenes and then dip-treated for 5 min in one of the following treatments: sterile tap water, chlorinated water, 1% lemon essential oil, 2% cinnamon essential oil or 2% cinnamon essential oil + ultrasound. The samples were stored at 4 ℃ and collected at d 0, 1, 3, 5, 7 and 9 post inoculation. The 1% lemon (4 log) and 2% cinnamon (2 log) essential oil washes provided partial inhibition against L. monocytogenes by d 1. The combined application of 2% cinnamon oil and ultrasound resulted in only 0.85 log inhibition by d 1; however, the number of L. monocytogenes increased during storage and became nearly equal to the control at d 9. Therefore, different combinations of essential oils with other antimicrobials or novel technologies are required. © The Author(s) 2015.

  2. Radiation sensitivities of Listeria monocytogenes isolated from chicken meat and their growth at refrigeration temperatures

    International Nuclear Information System (INIS)

    Harsojo; Banati, D.; Ito, H.

    1997-01-01

    Listeria monocytogenes were isolated in 5 lots, more than one cell in each 25-g sample of 10 lots of chicken meat, which was obtained from several different areas in Japan. From taxonomic study, the psychrotrophic type of 3 isolates grew well at 4°C on Trypticase soy agar slant, whereas 2 isolates grew poorly. Cells of all isolates were sensitive to γ-irradiation in phosphate buffer, and the D 10 values obtained were 0.16 to 0.18 kGy under aerobic irradiation conditions similar to the values of salmonellae. In the chicken meat sample, the D 10 value obtained was 0.42 kGy the same value as in phosphate buffer under anaerobic irradiation conditions, and the necessary dose for inactivation of L. monocytogenes was estimated to be 2 kGy in raw chicken meat below 10 -4 CFU (colony forming unit) per gram. In the storage study of chicken meat which was inoculated with about 3×10 3 CFU per gram of L. monocytogenes, the psychrotrophic type of the isolates grew quickly at 7 to 10°C storage. However, a dose of 1 kGy was also effective to suppress the growth of L. monocytogenes at refrigeration temperatures below 10°C

  3. Modelling the growth of Listeria monocytogenes in fresh green coconut (Cocos nucifera L.) water.

    Science.gov (United States)

    Walter, Eduardo H M; Kabuki, Dirce Y; Esper, Luciana M R; Sant'Ana, Anderson S; Kuaye, Arnaldo Y

    2009-09-01

    The behaviour of Listeria monocytogenes in the fresh coconut water stored at 4 degrees C, 10 degrees C and 35 degrees C was studied. The coconut water was aseptically extracted from green coconuts (Cocos nucifera L.) and samples were inoculated in triplicate with a mixture of 5 strains of L. monocytogenes with a mean population of approximately 3 log(10) CFU/mL. The kinetic parameters of the bacteria were estimated from the Baranyi model, and compared with predictions of the Pathogen Modelling Program so as to predict its behaviour in the beverage. The results demonstrated that fresh green coconut water was a beverage propitious for the survival and growth of L. monocytogenes and that refrigeration at 10 degrees C or 4 degrees C retarded, but did not inhibit, growth of this bacterium. Temperature abuse at 35 degrees C considerably reduced the lagtimes. The study shows that L. monocytogenes growth in fresh green coconut water is controlled for several days by storage at low temperature, mainly at 4 degrees C. Thus, for risk population this product should only be drunk directly from the coconut or despite the sensorial alterations should be consumed pasteurized.

  4. Modeling the effect of temperature on survival rate of Listeria monocytogenes in yogurt.

    Science.gov (United States)

    Szczawiński, J; Szczawińska, M E; Łobacz, A; Jackowska-Tracz, A

    2016-01-01

    The aim of the study was to (i) evaluate the behavior of Listeria monocytogenes in a commercially produced yogurt, (ii) determine the survival/inactivation rates of L. monocytogenes during cold storage of yogurt and (iii) to generate primary and secondary mathematical models to predict the behavior of these bacteria during storage at different temperatures. The samples of yogurt were inoculated with the mixture of three L. monocytogenes strains and stored at 3, 6, 9, 12 and 15°C for 16 days. The number of listeriae was determined after 0, 1, 2, 3, 5, 7, 9, 12, 14 and 16 days of storage. From each sample a series of decimal dilutions were prepared and plated onto ALOA agar (agar for Listeria according to Ottaviani and Agosti). It was found that applied temperature and storage time significantly influenced the survival rate of listeriae (pbacteria was found in the samples stored at 6°C (D-10 value = 243.9 h), whereas the highest reduction in the number of the bacteria was observed in the samples stored at 15°C (D-10 value = 87.0 h). The number of L. monocytogenes was correlated with the pH value of the samples (pyogurt stored under temperature range from 3 to 15°C, however, the polynomial model gave a better fit to the experimental data.

  5. Exposure to minimally processed pear and melon during shelf life could modify the pathogenic potential of Listeria monocytogenes.

    Science.gov (United States)

    Colás-Medà, Pilar; Viñas, Inmaculada; Oliveira, Márcia; Anguera, Marina; Serrano, Jose C E; Abadias, Maribel

    2017-04-01

    Survival and virulence of foodborne pathogens can be influenced by environmental factors such as the intrinsic properties of food as well as the extrinsic properties that contribute to food shelf life (e.g., temperature and gas atmosphere). The direct contribution of food matrix characteristics on the survival of L. monocytogenes during fresh-cut fruit shelf life is not very well understood. In addition, the gastrointestinal tract is the primary route of listeriosis infection and penetration of the intestinal epithelial cell barrier is the first step in the infection process. Hence, the pathogenic potential of L. monocytogenes, measured as the capability for the organism to survive a simulated gastrointestinal tract and the proportion of cells able to subsequently adhere to and invade differentiated Caco-2 cells, subjected to fresh-cut pear and melon shelf life, was investigated. Samples were inoculated, stored at 10 °C for 7 days and evaluated after inoculation and again after 2 and 7 days of storage. A decrease in L. monocytogenes' capacity to survive a simulated gastrointestinal tract was observed with increasing storage time, regardless of the fruit matrix evaluated. Furthermore, L. monocytogenes placed on fresh-cut pear and melon was subjected to an attachment and invasion assay after crossing the simulated gastrointestinal tract. After inoculation, pathogen on fresh-cut pear showed 5-fold more capacity to adhere to Caco-2 cells than pathogen on fresh-cut melon. After 2 days of storage, L. monocytogenes grown on fresh-cut melon showed similar adhesive capacity (1.11%) than cells grown on pear (1.83%), but cells grown on melon had the higher invasive capacity (0.0093%). We can conclude that minimally processed melon could represent a more important hazard than pear under the studied shelf life. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Purification of leucocin A for use on wieners to inhibit Listeria monocytogenes in the presence of spoilage organisms.

    Science.gov (United States)

    Balay, Danielle R; Dangeti, Ramana V; Kaur, Kamaljit; McMullen, Lynn M

    2017-08-16

    The aims of this study were to improve the method for purification of leucocin A to increase yield of peptide and to evaluate the efficacy of leucocin A and an analogue of leucocin A (leucocin N17L) to inhibit the growth of Listeria monocytogenes on wieners in the presence of spoilage organisms. Leucocin A was produced by Leuconostoc gelidum UAL187 and purified with a five-fold increase in yield; leucocin N17L was synthesized replacing asparagine at residue 17 with leucine. Five strains of L. monocytogenes associated with foodborne illness were used to assess bacteriocin efficacy in vitro and in situ. Minimum inhibitory concentrations could not be determined in broth; however, on agar the minimum inhibitory concentrations ranged from 11.7-62.5μM and 62.5->500μM for leucocin A and leucocin N17L, respectively. Leucocin N17L was less effective than the native bacteriocin at controlling the growth of L. monocytogenes. The inactivation profiles of L. monocytogenes in broth in the presence of leucocin A suggested each isolate had different levels of resistance to the bacteriocin as determined by the initial bactericidal effect. The formation of spontaneously resistance subpopulations were also observed for each strain of L. monocytogenes. In situ, wieners were inoculated with the spoilage organisms, Carnobacterium divergens and Brochothrix thermosphacta, followed by surface application of purified leucocin A, and inoculated with a cocktail of L. monocytogenes. Wieners were vacuum packaged and stored at 7°C for 16d. Leucocin A reduced the counts L. monocytogenes on wieners during storage, regardless of the presence of C. divergens. B. thermosphacta was unaffected by the presence of leucocin A on wieners over the duration of storage. This study suggests that leucocin A may be beneficial to industry as a surface application on wieners to help reduce L. monocytogenes counts due to post-processing contamination even in the presence of spoilage organisms. However, further

  7. Inoculation Expedition of Agar wood

    International Nuclear Information System (INIS)

    Peng, C.S.; Mohd Fajri Osman; Rusli Zakaria

    2015-01-01

    Inoculation expedition of agar wood is a main field works for researcher in Nuclear Malaysia to prove the real inoculation of agar wood in real jungle. These expeditions was conducted fourth times in the jungles of Malaysia including Gunung Tebu in Terengganu, Murum in Belaga, Sarawak, Kampung Timbang in Kota Belud, Sabah and Nuclear Malaysia itself. This expedition starts from preparation of samples and equipment, transportation into the jungle, searching and recognition of agar wood and lastly, inoculation of the agar wood. Safety aspects precedence set out in the preparation and implementation of this expedition. (author)

  8. Microstructural examination of V-(4-5%) Cr-(4-5%)Ti irradiated in X530

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States); Chung, H.M. [Argonne Natinonal Lab., IL (United States)

    1997-08-01

    Microstructural examination results are reported for two heats of V-(4-5%)Cr-(4-5%)Ti irradiated in the X530 experiment to {approximately}400{degrees}C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to be affected by preirradiation heat treatment at 950-1125{degrees}C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations.

  9. Atlas(®) Listeria monocytogenes LmG2 Detection Assay Using Transcription Mediated Amplification to Detect Listeria monocytogenes in Selected Foods and Stainless Steel Surface.

    Science.gov (United States)

    Bres, Vanessa; Yang, Hua; Hsu, Ernie; Ren, Yan; Cheng, Ying; Wisniewski, Michele; Hanhan, Maesa; Zaslavsky, Polina; Noll, Nathan; Weaver, Brett; Campbell, Paul; Reshatoff, Michael; Becker, Michael

    2014-01-01

    The Atlas Listeria monocytogenes LmG2 Detection Assay, developed by Roka Bioscience Inc., was compared to a reference culture method for seven food types (hot dogs, cured ham, deli turkey, chicken salad, vanilla ice cream, frozen chocolate cream pie, and frozen cheese pizza) and one surface (stainless steel, grade 316). A 125 g portion of deli turkey was tested using a 1:4 food:media dilution ratio, and a 25 g portion for all other foods was tested using 1:9 food:media dilution ratio. The enrichment time and media for Roka's method was 24 to 28 h for 25 g food samples and environmental surfaces, and 44 to 48 h for 125 g at 35 ± 2°C in PALCAM broth containing 0.02 g/L nalidixic acid. Comparison of the Atlas Listeria monocytogenes LmG2 Detection Assay to the reference method required an unpaired approach. For each matrix, 20 samples inoculated at a fractional level and five samples inoculated at a high level with a different strain of Listeria monocytogenes were tested by each method. The Atlas Listeria monocytogenes LmG2 Detection Assay was compared to the Official Methods of Analysis of AOAC INTERNATIONAL 993.12 method for dairy products, the U.S. Department of Agriculture, Food Safety and Inspection Service, Microbiology Laboratory Guidebook 8.08 method for ready-to-eat meat and environmental samples, and the U.S. Food and Drug Administration Bacteriological Analytical Manual, Chapter 10 method for frozen foods. In the method developer studies, Roka's method, at 24 h (or 44 h for 125 g food samples), had 126 positives out of 200 total inoculated samples, compared to 102 positives for the reference methods at 48 h. In the independent laboratory studies, vanilla ice cream, deli turkey and stainless steel grade 316 were evaluated. Roka's method, at 24 h (or 44 h for 125 g food samples), had 64 positives out of 75 total inoculated samples compared to 54 positives for the reference methods at 48 h. The Atlas Listeria monocytogenes LmG2 Detection Assay detected all 50

  10. Inoculation in Political Campaign Communication.

    Science.gov (United States)

    Pfau, Michael; Burgoon, Michael

    1988-01-01

    Posits a strategy of resistance to the influence of attack messages in political campaigns. Finds that political campaign messages can be designed to inoculate supporters of candidates against subsequent attack messages of opposing candidates. (MS)

  11. Inhibition of Listeria monocytogenes on Ready-to-Eat Meats Using Bacteriocin Mixtures Based on Mode-of-Action

    Directory of Open Access Journals (Sweden)

    Paul Priyesh Vijayakumar

    2017-03-01

    Full Text Available Bacteriocin-producing (Bac+ lactic acid bacteria (LAB comprising selected strains of Lactobacillus curvatus, Lactococcus lactis, Pediococcus acidilactici, and Enterococcus faecium and thailandicus were examined for inhibition of Listeria monocytogenes during hotdog challenge studies. The Bac+ strains, or their cell-free supernatants (CFS, were grouped according to mode-of-action (MOA as determined from prior studies. Making a mixture of as many MOAs as possible is a practical way to obtain a potent natural antimicrobial mixture to address L. monocytogenes contamination of RTE meat products (i.e., hotdogs. The heat resistance of the bacteriocins allowed the use of pasteurization to eliminate residual producer cells for use as post-process surface application or their inclusion into hotdog meat emulsion during cooking. The use of Bac+ LAB comprising 3× MOAs directly as co-inoculants on hotdogs was not effective at inhibiting L. monocytogenes. However, the use of multiple MOA Bac+ CFS mixtures in a variety of trials demonstrated the effectiveness of this approach by showing a >2-log decrease of L. monocytogenes in treatment samples and 6–7 log difference vs. controls. These data suggest that surface application of multiple mode-of-action bacteriocin mixtures can provide for an Alternative 2, and possibly Alternative 1, process category as specified by USDA-FSIS for control of L. monocytogenes on RTE meat products.

  12. Listeria monocytogenes inhibition by defatted mustard meal-based edible films.

    Science.gov (United States)

    Lee, Hahn-Bit; Noh, Bong Soo; Min, Sea C

    2012-02-01

    An antimicrobial edible film was developed from defatted mustard meal (Sinapis alba) (DMM), a byproduct from the bio-fuel industry, without incorporating external antimicrobials and its antimicrobial activity against Listeria monocytogenes and physical properties were investigated. The DMM colloidal solution consisting of 184 g water, 14 g DMM, and 2g glycerol was homogenized and incubated at 37°C for 0.2, 0.5, 24 or 48 h to prepare a film-forming solution. The pH of a portion of the film-forming solution (pH 5.5) was adjusted to 2.0 or 4.0. Films were formed by drying the film-forming solutions at 23°C for 48 h. The film-forming solution incubated for 48 h inhibited L. monocytogenes in broth and on agar media. Antimicrobial effects of the film prepared from the 48 h-incubated solution increased with decrease in pH of the solution from 5.5 to 2.0. The film from the film forming solution incubated for 48 h (pH 2.0) initially inhibited more than 4.0 log CFU/g of L. monocytogenes inoculated on film-coated salmon. The film-coating retarded the growth of L. monocytogenes in smoked salmon at 5, 10, and 15°C and the antimicrobial effect during storage was more noticeable when the coating was applied before inoculation than when it was applied after inoculation. The tensile strength, percentage elongation, solubility in watercxu, and water vapor permeability of the anti microbial film were 2.44 ± 0.19 MPa, 6.40 ± 1.13%, 3.19 ± 0.90%, and 3.18 ± 0.63 gmm/kPa hm(2), respectively. The antimicrobial DMM films have demonstrated a potential to be applied to foods as wraps or coatings to control the growth of L. monocytogenes. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Assessment of Listeria monocytogenes virulence in the Galleria mellonella insect larvae model.

    Directory of Open Access Journals (Sweden)

    Mira Rakic Martinez

    Full Text Available Several animal models have been used to understand the molecular basis of the pathogenicity, infectious dose and strain to strain variation of Listeria monocytogenes. The greater wax worm Galleria mellonella, as an alternative model, provides some useful advantages not available with other models and has already been described as suitable for the virulence assessment of various pathogens including L. monocytogenes. The objectives of this study are: 1 confirming the usefulness of this model with a wide panel of Listeria spp. including non-pathogenic L. innocua, L. seeligeri, L. welshimeri and animal pathogen L. ivanovii; 2 assessment of virulence of several isogenic in-frame deletion mutants in virulence and stress related genes of L. monocytogenes and 3 virulence assessment of paired food and clinical isolates of L. monocytogenes from 14 major listeriosis outbreaks occurred worldwide between 1980 and 2015. Larvae injected with different concentrations of Listeria were incubated at 37°C and monitored over seven days for time needed to kill 50% of larvae (LT50 and to determine change of bacterial population in G. mellonella, 2 and 24 hours post-inoculation. Non-pathogenic members of Listeria and L. ivanovii showed significantly (P < 0.05 higher LT50 (lower virulence than the wild type L. monocytogenes strains. Isogenic mutants of L. monocytogenes with the deletions in prfA, plcA, hly, actA and virR genes, also showed significantly (P < 0.05 higher LT50 than the wild type strain at the inoculum of 106CFU/larva. Food isolates had significantly (P < 0.05 lower virulence than the paired clinical isolates, at all three inoculum concentrations. L. monocytogenes strains related to non-invasive (gastroenteritis outbreaks of listeriosis showed significantly (P < 0.05 lower virulence than isolates of the same serotype obtained from outbreaks with invasive symptoms. The difference, however, was dose and strain- dependent. No significant differences in

  14. Solar irradiance limits the long-term survival of Listeria monocytogenes in seawater.

    Science.gov (United States)

    NicAogáin, K; Magill, D; O'Donoghue, B; Conneely, A; Bennett, C; O'Byrne, C P

    2018-03-01

    Seafood has often been implicated in outbreaks of food-borne illness caused by Listeria monocytogenes but the source of contamination is usually not known. In this study we investigated the possibility that this pathogen could survive in seawater for an extended time period. Freshly collected seawater samples were inoculated with 1 × 10 8  CFU per ml of L. monocytogenes EGD-e and survival was monitored by plate counting for up to 25 days. When incubated in the dark, either at ambient temperatures (4-14°C) or at 16°C, >10 4  CFU per ml survivors were present after 25 days. However, when the seawater cell suspensions were exposed to ambient light (solar irradiation) and temperatures, L. monocytogenes lost viability rapidly and no survivors could be detected after the 80 h time point. Both UV-A and visible light in the blue region of the spectrum (470 nm) were found to contribute to this effect. The stress inducible sigma factor σ B was found to play a role in survival of L. monocytogenes in seawater. Together these data demonstrate that solar irradiation is a critical determinant of L. monocytogenes survival in marine environments. The data further suggest the possibility of controlling this food-borne pathogen in food-processing environments using visible light. Listeria monocytogenes is a food-borne bacterial pathogen capable of causing the life-threatening infection, listeriosis. In seafood the route of contamination from the environment is often not well understood as this pathogen is not generally thought to survive well in seawater. Here we provide evidence that L. monocytogenes is capable of surviving for long periods of time in seawater when light is excluded. Sunlight is demonstrated to have a significant effect on the survival of this pathogen in seawater, and both visible (470 nm) and UV-A light are shown to contribute to this effect. © 2017 The Society for Applied Microbiology.

  15. Growth potential of Listeria monocytogenes in sliced turkey bresaola packed in modified atmosphere

    Directory of Open Access Journals (Sweden)

    Elena Dalzini

    2014-02-01

    Full Text Available According to EC Regulation No 2073/2005, for food business operators that produce ready-to-eat (RTE product, it is crucial to be able to demonstrate if the product supports the growth of Listeria monocytogenes. The objective of the study was therefore to evaluate the behaviour of L. monocytogenes in sliced RTE turkey bresaola (made by cured turkey breast 4.5% NaCl, 1% sodium lactate, sodium nitrite 150 ppm and flavouring during the shelf life of the product, simulating a contamination during the slicing operation. Considering a shelf life of 90 days, as defined by manufacturer, the packages of sliced bresaola were stored at 5°C for 7 days and at 8°C for the remaining storage time (83 days. L. monocytogenes count decreased during storage test from 1.43/1.98 log cfu/g in the three batches tested to 1.03 log cfu/g in one batch and to undetectable levels in the other two batches. The results show that the investigated product is unable to support the growth of L. monocytogenes.

  16. Effect of packaging and storage time on survival of Listeria monocytogenes on kippered beef steak and turkey tenders.

    Science.gov (United States)

    Uppal, Kamaldeep K; Getty, Kelly J K; Boyle, Elizabeth A E; Harper, Nigel M; Lobaton-Sulabo, April Shayne S; Barry, Bruce

    2012-01-01

    The objective of our study was to determine effect of packaging method and storage time on reducing Listeria monocytogenes in shelf-stable meat snacks. Commercially available kippered beef steak strips and turkey tenders were dipped into a 5-strain L. monocytogenes cocktail, and dried at 23 °C until a water activity of 0.80 was achieved. Inoculated samples were packaged with 4 treatments: (1) vacuum, (2) nitrogen flushed with oxygen scavenger, (3) heat sealed with oxygen scavenger, and (4) heat sealed without oxygen scavenger. Samples were stored at 23 °C and evaluated for L. monocytogenes levels at 0, 24, 48, and 72 h. Initial levels (time 0) of L. monocytogenes were approximately 5.7 log CFU/cm² for steak and tenders. After 24 h of storage time, a 1 log CFU/cm² reduction of L. monocytogenes was observed for turkey tenders for all packaging treatments. After 48 h, turkey tenders showed >1 log CFU/cm² reduction of L. monocytogenes for all packaging treatments except for vacuum, where only 0.9 log CFU/cm² reduction was observed. After 72 h, reductions for all packaging treatments for turkey tenders ranged from 1.5 to 2.4 log CFU/cm². For kippered beef steak, there was no interaction between the packaging treatments and all storage times (P > 0.05) whereas, time was different (P packaging treatments and a 2.1 log CFU/ cm² L. monocytogenes reduction at 72 h of storage time. Processors of kippered beef steak and turkey tenders could use a combination of vacuum or nitrogen-flushing or heat sealed with an oxygen scavenger packaging methods and a holding time of 24 h prior to shipping to reduce potential L. monocytogenes numbers by ≥1 log. However, processors should be encouraged to hold packaged product a minimum of 72 h to enhance the margin of safety for L. monocytogenes control. © 2011 Institute of Food Technologists®

  17. Biological Inoculants in Forage Conservation

    Directory of Open Access Journals (Sweden)

    Judit Peter Szucs

    2011-05-01

    Full Text Available 3rd generation biological inoculants –containing lactic acid bacteria and enzymes – are prefered nowadays in order to coordinate the fermentation in such a way that they increase lactic acid production by leaps and bounds at the beginning of the fermentation and improve the quality and stability of silage during the fermentation and feeding. The quality of raw material (maturity of plant, chop lenght, spreading of inoculant uniformly and the proper filling, compacting, covering and wrapping have a great influence on the effectiveness of the inoculant. The mycotoxin content of malfermented silages is an undesirable risk factor. The authors established, that the Lactobacillus buchneri and enzymes containing inoculant protected better the carotene content of low, medium- and high wilteed lucerne haylages (P<0,05 compare to untreated ones Aerobic stability experiment by Honnig 1990 method was carried out with medium wilted (36 % DM lucerne haylage which was treatedtreated before ensilage with , the dosage of 105 CFU/g Pediococcus acidilactici, 1,5x105 CFU/g Lactobacillus buchneri and cellulase and hemicellulase enzimes (20 000 CMC /g remained stabyle, unspoiled after 9 days exposure to the air, while the untreated haylages spoiled after 2;4;or 7days on aerobic condition. The different Lactobacillus plantarum strains (50.000 CFU of Lactobacillus plantarum DSM 16568 + 50.000 CFU of Lactobacillus plantarum DSM 4784/ g FM of maize applied together were able to improve the aerobic stability of silomaize silage.

  18. Characteristics of 2,4,5,2',4',5'-hexachlorobiphenyl distribution among lipoproteins in vitro

    International Nuclear Information System (INIS)

    Vomachka, M.S.; Vodicnik, M.J.; Lech, J.J.

    1983-01-01

    The uptake, distribution, and transfer of 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) were examined in vitro with human and rat whole blood, plasma, and lipoprotein fractions. 6-CB distribution between plasma and erythrocytes as well as among lipoproteins was determined following sedimentation of erythrocytes and ultracentrifugal fractionation of plasma. In both rat and human whole blood, 70 to 75% of 6-CB partitioned into plasma and 25 to 30% into erythrocytes. The uptake of 6-CB into plasma was extremely rapid and the rate of uptake was found to be dependent upon temperature. The distribution of 6-CB among lipoproteins was relatively homogeneous with 20 to 30% being distributed in very low-density lipoproteins (VLDL, d . 0.95-1.006 g/ml), 15 to 20% in low-density lipoproteins (LDL, d . 1.006-1.063 g/ml), and 15 to 25% in high-density lipoproteins (HDL, d . 1.063-1.21 g/ml). Over 25% of 6-CB was found in the remaining bottom fraction. In addition, each isolated fraction when incubated alone with 6-CB was shown capable of uptake. The relative proportion of 6-CB among the lipoproteins was independent of the level taken up by plasma. 6-CB was also found to transfer among lipoproteins. This exchange of 6-CB proved to be dependent upon the concentrations of both protein and triacylglycerol in the incubations. Two proteins in the bottom fraction (Bf), albumin and a steroid binding globulin, were capable of competing with the lipoproteins for 6-CB uptake

  19. Highly specific fiber optic immunosensor coupled with immunomagnetic separation for detection of low levels of Listeria monocytogenes and L. ivanovii

    Science.gov (United States)

    2012-01-01

    Background Immunomagnetic separation (IMS) and immunoassays are widely used for pathogen detection. However, novel technology platforms with highly selective antibodies are essential to improve detection sensitivity, specificity and performance. In this study, monoclonal antibodies (MAbs) against Internalin A (InlA) and p30 were generated and used on paramagnetic beads of varying diameters for concentration, as well as on fiber-optic sensor for detection. Results Anti-InlA MAb-2D12 (IgG2a subclass) was specific for Listeria monocytogenes and L. ivanovii, and p30-specific MAb-3F8 (IgM) was specific for the genus Listeria. At all bacterial concentrations (103–108 CFU/mL) tested in the IMS assay; the 1-μm diameter MyOne beads had significantly higher capture efficiency (P Listeria antibody (9 %). Furthermore, capture efficiency for MyOne-2D12 was highly specific for L. monocytogenes and L. ivanovii. Subsequently, we captured L. monocytogenes by MyOne-2D12 and MyOne-3F8 from hotdogs inoculated with mono- or co-cultures of L. monocytogenes and L. innocua (10–40 CFU/g), enriched for 18 h and detected by fiber-optic sensor and confirmed by plating, light-scattering, and qPCR assays. The detection limit for L. monocytogenes and L. ivanovii by the fiber-optic immunosensor was 3 × 102 CFU/mL using MAb-2D12 as capture and reporter antibody. Selective media plating, light-scattering, and qPCR assays confirmed the IMS and fiber-optic results. Conclusions IMS coupled with a fiber-optic sensor using anti-InlA MAb is highly specific for L. monocytogenes and L. ivanovii and enabled detection of these pathogens at low levels from buffer or food. PMID:23176167

  20. 45 CFR 4.5 - Effect of regulations.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Effect of regulations. 4.5 Section 4.5 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION SERVICE OF PROCESS § 4.5 Effect of regulations. The regulations in this part are intended solely to identify Department officials who are...

  1. Pregnancy - associated human listeriosis: Virulence and genotypic analysis of Listeria monocytogenes from clinical samples.

    Science.gov (United States)

    Soni, Dharmendra Kumar; Singh, Durg Vijai; Dubey, Suresh Kumar

    2015-09-01

    Listeria monocytogenes, a life-threatening pathogen, poses severe risk during pregnancy, may cause abortion, fetal death or neonatal morbidity in terms of septicemia and meningitis. The present study aimed at characterizing L. monocytogenes isolated from pregnant women based on serotyping, antibiotic susceptibility, virulence genes, in vivo pathogenicity test and ERIC- and REP-PCR fingerprint analyses. The results revealed that out of 3700 human clinical samples, a total of 30 (0.81%) isolates [12 (0.80%) from placental bit (1500), 18 (0.81%) from vaginal swab (2200)] were positive for L. monocytogenes. All the isolates belonged to serogroup 4b, and were + ve for virulence genes tested i.e. inlA, inlC, inlJ, plcA, prfA, actA, hlyA, and iap. Based on the mice inoculation tests, 20 isolates showed 100% and 4 isolates 60% relative virulence while 6 isolates were non-pathogenic. Moreover, 2 and 10 isolates were resistant to ciprofloxacin and cefoxitin, respectively, while the rest susceptible to other antibiotics used in this study. ERIC- and REP-PCR collectively depicted that the isolates from placental bit and vaginal swab had distinct PCR fingerprints except a few isolates with identical patterns. This study demonstrates prevalence of pathogenic strains mostly resistant to cefoxitin and/or ciprofloxacin. The results indicate the importance of isolating and characterizing the pathogen from human clinical samples as the pre-requisite for accurate epidemiological investigations.

  2. Survival of bioluminescent Listeria monocytogenes and Escherichia coli O157:H7 in soft cheeses.

    Science.gov (United States)

    Ramsaran, H; Chen, J; Brunke, B; Hill, A; Griffiths, M W

    1998-07-01

    Pasteurized and raw milks that had been inoculated at 10(4) cfu/ml with bioluminescent strains of Listeria monocytogenes and Escherichia coli O157:H7 were used in the manufacture of Camembert and Feta cheeses with or without nisin-producing starter culture. Survival of both organisms was determined during the manufacture and storage of Camembert and Feta cheeses at 2 +/- 1 degree C for 65 and 75 d, respectively. Bacterial bioluminescence was used as an indicator to enumerate the colonies plated on selective Listeria agar and on MacConkey agar. Escherichia coli O157:H7 survived the manufacturing process of both cheeses and was present at the end of the storage period in greater numbers than in the initial inoculum. At the end of 75 d of storage, E. coli O157:H7 was found in the brine of Feta cheese. The counts of L. monocytogenes increased as the pH of the Camembert cheese increased, and there were significant differences between the counts from samples taken from the inside and the counts from samples obtained near the surface of the cheese. The Feta cheese that contained nisin was the only cheese in which L. monocytogenes was at the level of the initial inoculum after 75 d of storage.

  3. Behavior of Escherichia coli O157:H7 and Listeria monocytogenes during fermentation and storage of camel yogurt.

    Science.gov (United States)

    Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Ayyash, Mutamed M; Abushelaibi, Aisha; Jaradat, Ziad W; Shaker, Reyad; Al-Taani, Mahmoud; Holley, Richard A

    2016-03-01

    In addition to its nutritional and therapeutic properties, camel milk has the ability to suppress the growth of a wide range of foodborne pathogens, but there is a lack of information regarding the behavior of these pathogens in products such as yogurt produced from camel milk. The objective of the current study was to investigate the behavior of Listeria monocytogenes and Escherichia coli O157:H7 during manufacture and storage of camel yogurt. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 was fermented at 43° C for 5h using freeze-dried lactic acid bacteria (LAB) starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) and stored at 4 or 10 °C for 14 d. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 without starter culture was also prepared. During fermentation, the numbers of L. monocytogenes and E. coli O157:H7 increased 0.3 and 1.6 log cfu/mL, respectively, in the presence of LAB, and by 0.3 and 2.7 log cfu/mL in the absence of LAB. During storage at 4 or 10 °C, L. monocytogenes increased 0.8 to 1.2 log cfu/mL by 14 d in camel milk without LAB, but in the presence of LAB, the numbers of L. monocytogenes were reduced by 1.2 to 1.7 log cfu/mL by 14 d. Further, E. coli O157:H7 numbers in camel milk were reduced by 3.4 to 3.5 log cfu/mL in the absence of LAB, but E. coli O157:H7 was not detected (6.3 log cfu/mL reduction) by 7d in camel yogurt made with LAB and stored at either temperature. Although camel milk contains high concentrations of natural antimicrobials, L. monocytogenes was able to tolerate these compounds in camel yogurt stored at refrigerator temperatures. Therefore, appropriate care should be taken during production of yogurt from camel milk to minimize the potential for postprocess contamination by this and other foodborne pathogens. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Phosphatidylinositol 4,5-bisphosphate optical uncaging potentiates exocytosis

    DEFF Research Database (Denmark)

    Walter, Alexander M; Müller, Rainer; Tawfik, Bassam

    2017-01-01

    Phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] is essential for exocytosis. Classical ways of manipulating PI(4,5)P2 levels are slower than metabolism, making it difficult to distinguish effects of PI(4,5)P2 from those of its metabolites. We developed a membrane-permeant, photoactivatable PI(4......,5)P2, which is loaded into cells in an inactive form and activated by light, allowing sub-second increases in PI(4,5)P2 levels. By combining this compound with electrophysiological measurements in mouse adrenal chromaffin cells, we show that PI(4,5)P2 uncaging potentiates exocytosis and identify...... synaptotagmin-1 (the Ca(2+) sensor for exocytosis) and Munc13-2 (a vesicle priming protein) as the relevant effector proteins. PI(4,5)P2 activation of exocytosis did not depend on the PI(4,5)P2-binding CAPS-proteins, suggesting that PI(4,5)P2 uncaging bypasses CAPS-function. Finally, PI(4,5)P2 uncaging...

  5. A novel model to assess the efficacy of steam surface pasteurization of cooked surimi gels inoculated with realistic levels of Listeria innocua.

    Science.gov (United States)

    Skåra, Torstein; Valdramidis, Vasilis P; Rosnes, Jan Thomas; Noriega, Estefanía; Van Impe, Jan F M

    2014-12-01

    Steam surface pasteurization is a promising decontamination technology for reducing pathogenic bacteria in different stages of food production. The effect of the artificial inoculation type and initial microbial load, however, has not been thoroughly assessed in the context of inactivation studies. In order to optimize the efficacy of the technology, the aim of this study was to design and validate a model system for steam surface pasteurization, assessing different inoculation methods and realistic microbial levels. More specifically, the response of Listeria innocua, a surrogate organism of Listeria monocytogenes, on a model fish product, and the effect of different inoculation levels following treatments with a steam surface pasteurization system was investigated. The variation in the resulting inoculation level on the samples was too large (77%) for the contact inoculation procedure to be further considered. In contrast, the variation of a drop inoculation procedure was 17%. Inoculation with high levels showed a rapid 1-2 log decrease after 3-5 s, and then no further inactivation beyond 20 s. A low level inoculation study was performed by analysing the treated samples using a novel contact plating approach, which can be performed without sample homogenization and dilution. Using logistic regression, results from this method were used to model the binary responses of Listeria on surfaces with realistic inoculation levels. According to this model, a treatment time of 23 s will result in a 1 log reduction (for P = 0.1). Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Prior frozen storage enhances the effect of edible coatings against Listeria monocytogenes on cold-smoked salmon during subsequent refrigerated storage.

    Science.gov (United States)

    Ye, M; Neetoo, H; Chen, H

    2011-10-01

    Listeria monocytogenes is a major safety concern for ready-to-eat foods. The overall objective of this study was to investigate whether prior frozen storage could enhance the efficacy of edible coatings against L. monocytogenes on cold-smoked salmon during subsequent refrigerated storage. A formulation consisting of sodium lactate (SL, 1·2-2·4%) and sodium diacetate (SD, 0·125-0·25%) or 2·5% Opti.Form (a commercial formulation of SL and SD) was incorporated into each of five edible coatings: alginate, κ-carrageenan, pectin, gelatin and starch. The coatings were applied onto the surface of cold-smoked salmon slices inoculated with L. monocytogenes at a level of 500 CFU cm⁻². In the first phase, the slices were first frozen at -18°C for 6 days and stored at 22°C for 6 days. Alginate, gelatin and starch appeared to be the most effective carriers. In the second phase, cold-smoked salmon slices were inoculated with L. monocytogenes, coated with alginate, gelatin or starch with or without the antimicrobials and stored frozen at -18°C for 12 months. Every 2 months, samples were removed from the freezer and kept at 4°C for 30 days. Prior frozen storage at -18°C substantially enhanced the antilisterial efficacy of the edible coatings with or without antimicrobials during the subsequent refrigerated storage. Plain coatings with ≥ 2 months frozen storage and antimicrobial edible coatings represent an effective intervention to inhibit the growth of L. monocytogenes on cold-smoked salmon. This study demonstrates the effectiveness of the conjunct application of frozen storage and edible coatings to control the growth of L. monocytogenes to enhance the microbiological safety of cold-smoked salmon. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  7. Control of Listeria monocytogenes in goat's milk and goat's jben by the bacteriocinogenic Enterococcus faecium F58 strain.

    Science.gov (United States)

    Achemchem, Fouad; Abrini, Jamal; Martínez-Bueno, Manuel; Valdivia, Eva; Maqueda, Mercedes

    2006-10-01

    The bacteriocinogenic Enterococcus faecium F58 strain, a natural goat's jben cheese isolate, lacks decarboxylase activity involved in most biogenic amine formation. It was also sensitive to 13 antibiotics assayed and free of virulence and vancomycin resistance genes. The F58 strain reached the stationary phase after 12 h of growth in sterile goat's milk, and the production of enterocin F-58 (Ent L50) was first detected after 48 h (400 AU/ml), thereafter remaining stable up to 5 days. The effectiveness of the F58 strain in controlling Listeria monocytogenes serovar 4b in reduced fat and whole goat's milk, and in goat's jben has been examined. Coculture experiments of F58-L. monocytogenes in both types of milk demonstrated that listeriae were not eliminated, although reductions by 1 to 4 log units were found. Nevertheless, when the F58 strain was previously inoculated in whole milk and left to grow for 12 h before contamination, the pathogen was completely eliminated after 130 h of coculture. Production of jben cheese contaminated with L. monocytogenes prior to packaging, using preparations of F58-producer strain, caused a significant decrease in the number of viable listeriae, which were undetectable after 1 week of cheese storage at 22 degrees C. Altogether, results from this study suggest that E. faecium F58 strain may be used as an adjunct culture in cheese to control contamination and growth of L. monocytogenes by in situ enterocin production, thus providing an additional hurdle to enhance control of this pathogen.

  8. Inoculation Effects of Cast Iron

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2012-12-01

    Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

  9. Effect of inoculum size, bacterial species, type of surfaces and contact time to the transfer of foodborne pathogens from inoculated to non-inoculated beef fillets via food processing surfaces.

    Science.gov (United States)

    Gkana, E; Chorianopoulos, N; Grounta, A; Koutsoumanis, K; Nychas, G-J E

    2017-04-01

    The objective of the present study was to determine the factors affecting the transfer of foodborne pathogens from inoculated beef fillets to non-inoculated ones, through food processing surfaces. Three different levels of inoculation of beef fillets surface were prepared: a high one of approximately 10 7  CFU/cm 2 , a medium one of 10 5  CFU/cm 2 and a low one of 10 3  CFU/cm 2 , using mixed-strains of Listeria monocytogenes, or Salmonella enterica Typhimurium, or Escherichia coli O157:H7. The inoculated fillets were then placed on 3 different types of surfaces (stainless steel-SS, polyethylene-PE and wood-WD), for 1 or 15 min. Subsequently, these fillets were removed from the cutting boards and six sequential non-inoculated fillets were placed on the same surfaces for the same period of time. All non-inoculated fillets were contaminated with a progressive reduction trend of each pathogen's population level from the inoculated fillets to the sixth non-inoculated ones that got in contact with the surfaces, and regardless the initial inoculum, a reduction of approximately 2 log CFU/g between inoculated and 1st non-inoculated fillet was observed. S. Typhimurium was transferred at lower mean population (2.39 log CFU/g) to contaminated fillets than E. coli O157:H7 (2.93 log CFU/g), followed by L. monocytogenes (3.12 log CFU/g; P < 0.05). Wooden surfaces (2.77 log CFU/g) enhanced the transfer of bacteria to subsequent fillets compared to other materials (2.66 log CFU/g for SS and PE; P < 0.05). Cross-contamination between meat and surfaces is a multifactorial process strongly depended on the species, initial contamination level, kind of surface, contact time and the number of subsequent fillet, according to analysis of variance. Thus, quantifying the cross-contamination risk associated with various steps of meat processing and food establishments or households can provide a scientific basis for risk management of such products. Copyright © 2016 Elsevier Ltd

  10. Cleaning and Disinfection of Biofilms Composed of Listeria monocytogenes and Background Microbiota from Meat Processing Surfaces

    Science.gov (United States)

    Møretrø, Trond; Heir, Even; Briandet, Romain; Langsrud, Solveig

    2017-01-01

    ABSTRACT Surfaces of food processing premises are exposed to regular cleaning and disinfection (C&D) regimes, using biocides that are highly effective against bacteria growing as planktonic cells. However, bacteria growing in surface-associated communities (biofilms) are typically more tolerant toward C&D than their individual free-cell counterparts, and survival of pathogens such as Listeria monocytogenes may be affected by interspecies interactions within biofilms. In this study, Pseudomonas and Acinetobacter were the most frequently isolated genera surviving on conveyor belts subjected to C&D in meat processing plants. In the laboratory, Pseudomonas, Acinetobacter, and L. monocytogenes dominated the community, both in suspensions and in biofilms formed on conveyor belts, when cultures were inoculated with eleven-genus cocktails of representative bacterial strains from the identified background flora. When biofilms were exposed to daily C&D cycles mimicking treatments used in food industry, the levels of Acinetobacter and Pseudomonas mandelii diminished, and biofilms were instead dominated by Pseudomonas putida (65 to 76%), Pseudomonas fluorescens (11 to 15%) and L. monocytogenes (3 to 11%). The dominance of certain species after daily C&D correlated with high planktonic growth rates at 12°C and tolerance to C&D. In single-species biofilms, L. monocytogenes developed higher tolerance to C&D over time, for both the peracetic acid and quaternary ammonium disinfectants, indicating that a broad-spectrum mechanism was involved. Survival after C&D appeared to be a common property of L. monocytogenes strains, as persistent and sporadic subtypes showed equal survival rates in complex biofilms. Biofilms established preferentially in surface irregularities of conveyor belts, potentially constituting harborage sites for persistent contamination. IMPORTANCE In the food industry, efficient production hygiene is a key measure to avoid the accumulation of spoilage bacteria and

  11. Cleaning and disinfection of biofilms composed of Listeria monocytogenes and background microbiota from meat processing surfaces.

    Science.gov (United States)

    Fagerlund, Annette; Møretrø, Trond; Heir, Even; Briandet, Romain; Langsrud, Solveig

    2017-06-30

    Surfaces of food processing premises are exposed to regular cleaning and disinfection (C&D) regimes, using biocides that are highly effective against bacteria growing as planktonic cells. However, bacteria growing in surface associated communities (biofilms) are typically more tolerant towards C&D than their individual free cells counterparts, and survival of pathogens such as Listeria monocytogenes may be affected by interspecies interactions within biofilms. In this study, Pseudomonas and Acinetobacter were the most frequently isolated genera surviving on conveyor belts subjected to C&D in meat processing plants. In the laboratory, Pseudomonas , Acinetobacter and L. monocytogenes dominated the community both in suspensions and in biofilms formed on conveyor belts, when cultures were inoculated with eleven-genera cocktails of representative bacterial strains from the identified background flora. When biofilms were exposed to daily C&D cycles, mimicking treatments used in food industry, the levels of Acinetobacter and Pseudomonas mandelii diminished, and biofilms were instead dominated by Pseudomonas putida (65-76%), Pseudomonas fluorescens (11-15%) and L. monocytogenes (3-11%). The dominance of certain species after daily C&D correlated with high planktonic growth rates at 12°C and tolerance to C&D. In single-species biofilms, L. monocytogenes developed higher tolerance to C&D over time, both for the peracetic acid and quaternary ammonium disinfectant, indicating that a broad-spectrum mechanism was involved. Survival after C&D appeared to be a common property of L. monocytogenes strains, as both persistent and sporadic subtypes showed equal survival in complex biofilms. Biofilms established preferentially in surface irregularities of conveyor belts, potentially constituting harborage sites for persistent contamination. IMPORTANCE In food industry, efficient production hygiene is a key measure to avoid accumulation of spoilage bacteria and eliminate pathogens

  12. 78 FR 27939 - Draft Interagency Risk Assessment-Listeria monocytogenes

    Science.gov (United States)

    2013-05-13

    ... Listeria (L.) monocytogenes contamination of certain ready-to-eat (RTE) foods, for example cheese, deli... Scott, V.N., Survey of Listeria monocytogenes in ready-to-eat foods. Journal of Food Protection, 2003... monocytogenes in ready-to-eat processed meat and poultry collected in four FoodNet states in International...

  13. Occurrence of Listeria monocytogenes in smoked fish in Sokoto ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... monocytogenes and other Listeria species are common contaminant of smoked fish, and this may pose serious public health implications. Key words: Smoked fish, Listeria monocytogenes, contamination, public health. INTRODUCTION ... L. monocytogenes belong to the recently emerging psychrotrophic ...

  14. Listeria monocytogenes infection in pregnancy and neonatal sepsis

    Directory of Open Access Journals (Sweden)

    Francesca Pascale

    2008-06-01

    Full Text Available Authors report a fatal neonatal sepsis caused by Listeria monocytogenes. While the diagnostic procedure aimed to identify the microrganism is described, it is emphasized the importance to recover Streptococcus agalactiae (GBS and L. monocytogenes by means of vaginal-rectal swab culture. The intrapartum screening for L. monocytogenes, by Polymerase Chain Reaction (PCR providing results in 75 minutes is also evaluated.

  15. Bacteriophage biocontrol of Listeria monocytogenes on soft ripened white mold and red-smear cheeses.

    Science.gov (United States)

    Guenther, Susanne; Loessner, Martin J

    2011-03-01

    Soft-ripened cheeses belong to the type of food most often contaminated with Listeria monocytogenes, and they have been implicated in several outbreaks of listeriosis. Bacteriophages represent an attractive way to combat foodborne pathogens without affecting other properties of the food. We used the broad host range, virulent Listeria phage A511 for control of L. monocytogenes during the production and ripening phases of both types of soft-ripened cheeses, white mold (Camembert-type) cheese, as well as washed-rind cheese with a red-smear surface (Limburger-type). The surfaces of young, unripened cheese were inoculated with 10(1)-10(3) cfu/cm(2)L. monocytogenes strains Scott A (serovar 4b) or CNL 10(3)/2005 (serovar 1/2a). Phage was applied at defined time points thereafter, in single or repeated treatments, at 3 × 10(8) or 1 × 10(9) pfu/cm(2). With Scott A (10(3) cfu/cm(2)) and a single dose of A511 (3 × 10(8) pfu/cm(2)) on camembert-type cheese, viable counts dropped 2.5 logs at the end of the 21 day ripening period. Repeated phage application did not further inhibit the bacteria, whereas a single higher dose (1 × 10(9) pfu/cm(2)) was found to be more effective. On red-smear cheese ripened for 22 days, Listeria counts were down by more than 3 logs. Repeated application of A511 further delayed re-growth of Listeria, but did not affect bacterial counts after 22 days. With lower initial Listeria contamination (10(1)-10(2) cfu/cm(2)), viable counts dropped below the limit of detection, corresponding to more than 6 logs reduction compared to the control. Our data clearly demonstrate the potential of bacteriophage for biocontrol of L. monocytogenes in soft cheese.

  16. Modelling and predicting the simultaneous growth of Listeria monocytogenes and psychrotolerant lactic acid bacteria in processed seafood and mayonnaise-based seafood salads

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Dalgaard, Paw

    2015-01-01

    . using the classical Jameson effect to model microbial interaction. Maximum population density (MPD) values of L. monocytogenes were accurately predicted in processed seafood with a known initial cell concentration of Lactobacillus spp. For these experiments, average MPD values of 4.5 and 4.3 log (cfu...

  17. Prevalence of Listeria species in camel sausages from retail markets in Aydin province in Turkey and RAPD analysis of Listeria monocytogenes isolates

    OpenAIRE

    Ozbey, Gokben; Ertas, Hasan Basri; Kok, Filiz

    2006-01-01

    Abstract Samples were taken from 100 camel sausages from the different retail markets in Aydin province in the south-west of Turkey and they were tested for the presence of Listeria spp by biochemical methods. Samples were enriched using Listeria Enrichment Broth and they were inoculated onto Listeria Selective Agar. Listeria monocytogenes was isolated from nine samples (9%), Listeria innocua from 14 samples (14%) and Listeria welshimeri from two samples(2%). A 701 bp fragment of listeriolysi...

  18. Antimicrobial behavior of phage endolysin PlyP100 and its synergy with nisin to control Listeria monocytogenes in Queso Fresco.

    Science.gov (United States)

    Ibarra-Sánchez, Luis A; Van Tassell, Maxwell L; Miller, Michael J

    2018-06-01

    Hispanic-style fresh cheeses, such as Queso Fresco (QF), have been linked to numerous listeriosis outbreaks in the United States. In this work, we have studied the antilisterial behavior and effectiveness of the Listeria phage endolysin PlyP100 in QF, as well as the potential synergy between PlyP100 and nisin. PlyP100 showed similar bacterial reduction regardless of varying L. monocytogenes inoculum size in QF, and when the inoculation size was 1 Log CFU/g, no pathogen recovery after cheese enrichment was observed. PlyP100 was stable in QF for up to 28 days of cold storage exhibiting similar antilisterial activity regardless of when contamination with L. monocytogenes occurred. PlyP100 alone exhibited a strong listeriostatic effect in QF, on the contrary, nisin alone was not effective to control the pathogen in QF during cold storage. The combination of nisin and PlyP100 showed a strong synergy in QF with non-enumerable levels of L. monocytogenes after 4 weeks of refrigerated storage. Moreover, L. monocytogenes isolates from cheeses treated with nisin, PlyP100, and their combination did not develop resistance to nisin or PlyP100. Our results support the use of PlyP100 combined with nisin as an efficient L. monocytogenes control measure in QF. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

    Directory of Open Access Journals (Sweden)

    Martina Janoušková

    Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

  20. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Science.gov (United States)

    Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Inoculation with arbuscular mycorrhizal fungi (AMF) may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation. PMID:28738069

  1. Survival of Listeria monocytogenes and Salmonella typhimurium and quality attributes of cooked pork chops and cured ham after irradiation

    International Nuclear Information System (INIS)

    Fu, A.H.; Sebranek, J.G.; Murano, E.A.

    1995-01-01

    Cooked pork chops (pumped with salt/polyphosphate brine or untreated) and cured hams were inoculated with Listeria monocytogenes and Salmonella typhimurium. The samples were irradiated at low (0.75 to 0.90 kGy) or medium doses (1.8 to 2.0 kGy), and each dose was delivered at either a low (2.5 M/min conveyor speed) or high (5.4 M/min) dose rate. Low-dose irradiation reduced L. monocytogenes by more than 2 log and S. typhimurium by 1 to 3 log. Pathogen populations and total plate counts (TPC) were reduced to undetectable levels by medium doses. No meat quality attributes were affected, and no dose rate effect was observed. Nitrite reduced (P 0.05) both pathogens and TPC during 7 degrees C storage in ham, especially when combined with low-dose irradiation

  2. Synergistic effect of nisin and cone essential oil of Metasequoia glyptostroboides Miki ex Hu against Listeria monocytogenes in milk samples.

    Science.gov (United States)

    Yoon, Jung In; Bajpai, Vivek K; Kang, Sun Chul

    2011-01-01

    This study was undertaken to evaluate the effect of nisin and cone essential oil of Metasequoia glyptostroboides against Listeria monocytogenes ATCC 19116 inoculated in whole (8%), low (1%) and skim (no fat content) milks. Essential oil at the concentrations of 2% and 5% revealed strong antilisterial effect against L. monocytogenes ATCC 19116 in all categories of milks. Nisin at the concentrations of 250 and 500 IU/ml displayed a remarkable antilisterial effect as compared to the control group. Also, the synergistic combinations of cone essential oil (1% and 2%) and nisin (62.5, 125, 250 and 500 IU/ml) had a remarkable antilisterial activity in all categories of whole, low and skim milks after 14 days. Results of this study indicate that the cone essential oil of M. glyptostroboides might be a useful candidate for using in food industry to control the growth of pathogenic microorganisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Prevalence and growth of Listeria monocytogenes in naturally contaminated seafood

    DEFF Research Database (Denmark)

    Jørgensen, Lasse Vigel; Huss, Hans Henrik

    1998-01-01

    Listeria monocytogenes contamination of seafood varies with product category. The highest prevalence was found in cold- smoked fish (34-60%), while the lowest was found in heat- treated and cured seafood (4-12%). The prevalence of L. monocytogenes differed greatly in cold-smoked salmon between...... production sites, ranging from monocytogenes. The organism showed moderate growth...... in naturally contaminated cold-smoked, and 'gravad', fish while the growth appeared faster in hot smoked fish. Thus L. monocytogenes is not under control in these products. Finally, the prevalence and growth of L. monocytogenes in naturally contaminated cold-smoked salmon are discussed in relation...

  4. Effekt av ulike desinfeksjonsstrategier mot Listeria monocytogenes

    OpenAIRE

    Fossmo, Sabine

    2013-01-01

    Kontroll med bakterier som Listeria utgjør en stor utfordring for mange matprodusenter. Listeria monocytogenes er hovedsakelig et produksjonshygienisk problem, forbedret hygiene kan derfor være tiltak for å redusere overlevelse og smitteoverføring av bakterien i produksjonsmiljø. Hensikten med forsøkene i oppgaven var å undersøke effekten av ulike desinfeksjonsstrategier på drap av L. monocytogenes, både når bakteriene var i biofilm og i suspensjon. Dette inkluderte bruk av tradisjonelle desi...

  5. Assessing the capacity of growth, survival, and acid adaptive response of Listeria monocytogenes during storage of various cheeses and subsequent simulated gastric digestion.

    Science.gov (United States)

    Kapetanakou, Anastasia E; Gkerekou, Maria A; Vitzilaiou, Eirini S; Skandamis, Panagiotis N

    2017-04-04

    Different physicochemical and microbiological characteristics of cheeses may affect Listeria monocytogenes potential to grow, survive, or exhibit an acid adaptive response during storage and digestion. The objectives of the present study were to assess: i) the survival or growth potential of L.monocytogenes on various cheeses during storage, ii) the effect of initial indigenous microbiota on pathogen growth in comparison to expected growth curves retrieved by existing predictive models, and iii) the impact of habituation on/in cheeses surfaces on the subsequent acid resistance during simulated gastric digestion. Portions of cream (Cottage and Mascarpone), soft (Anthotyros, Camembert, Mastelo®, Manouri, Mozzarella, Ricotta), and semi-hard (Edam, Halloumi, Gouda) cheeses were inoculated with ca. 100CFU/g or cm 2 of L.monocytogenes and stored under vacuum or aerobic conditions at 7°C (n=4). The impact of varying (initial) levels of starter culture or indigenous spoilage microbiota on pathogen growth was evaluated by purchasing cheese packages on different dates in relation to production and expiration date (subsequently reflecting to different batches) mimicking a potential situation of cheese contamination with L.monocytogenes during retail display. Values of pH and a w were also monitored and used to simulate growth of L. monocytogenes by existing models and compare it with the observed data of the study. Survival in simulated gastric fluid (SGF) (pH1.5; HCl; max. 120min) was assessed at three time points during storage. Mascarpone, Ricotta, Mozzarella, Camembert, and Halloumi supported L.monocytogenes growth by 0.5-0.8logCFU/g or cm 2 per day, since low initial levels of total viable counts (TVC) (1.8-3.8logCFU/g or cm 2 ) and high pH/a w values (ca. 6.23-6.64/0.965-0.993) were recorded. On Cottage, Anthotyros, Manouri, Mastelo®, Edam, and Gouda, the pathogen survived at populations similar or lower than the inoculation level due to the high reported competition

  6. C4.5 programs for machine learning

    CERN Document Server

    Quinlan, J Ross

    1992-01-01

    Classifier systems play a major role in machine learning and knowledge-based systems, and Ross Quinlan's work on ID3 and C4.5 is widely acknowledged to have made some of the most significant contributions to their development. This book is a complete guide to the C4.5 system as implemented in C for the UNIX environment. It contains a comprehensive guide to the system's use , the source code (about 8,800 lines), and implementation notes. The source code and sample datasets are also available for download (see below). C4.5 starts with large sets of cases belonging to known classes. The cases,

  7. Prevalence of Listeria monocytogenes in poultry meat

    Directory of Open Access Journals (Sweden)

    Mehmet ELMALI

    2015-01-01

    Full Text Available AbstractThe objectives of this study were i to isolate Listeria spp. and Listeria monocytogenes in broiler wing meat samples, ii to confirm the isolates by PCR, based on prs and hly A gene sequences, iii to determine the seasonal and monthly distribution of the isolates. A total of 120 broiler wing meat samples (60 packaged pieces wrapped using strech film in styrofoam plates and 60 unpackaged pieces bought from different markets in Hatay province were analysed. Listeria spp. was isolated from 57 (47.5% out of 120 samples. Fifty-four, out of 57 Listeria spp. isolates were identified as L. monocytogenes. L. monocytogenes was isolated from the samples collected during the spring, winter, summer, and autumn at the levels of 26.6%, 40%, 53.3%, 60%, respectively. In this study, the isolation rates were found to be the highest in autumn, while the isolation rates were found to be the lowest in spring. As a consequence, high prevalence of Listeria spp. and L. monocytogenes in poultry wing meat samples may pose a risk for human health. We consider that with obeying the rules of good hygiene practices (GHP, good manufacturing practices (GMP and HACCP can minimize the contamination with Listeria spp.

  8. Control options for Listeria monocytogenes in seafoods

    DEFF Research Database (Denmark)

    Huss, Hans Henrik; Jørgensen, Lasse Vigel; Vogel, Birte Fonnesbech

    2000-01-01

    At least three outbreaks of listeriosis associated with seafood have been reported. Listeria monocytogenes is widely distributed in the general environment including fresh water, coastal water and live fish from these areas. Contamination or recontamination of seafood may also take place during...

  9. Listeria monocytogenes : nog steeds een probleem?

    NARCIS (Netherlands)

    Beumer, R.R.

    2011-01-01

    Listeria monocytogenes is net als vele andere bacteriële voedselpathogenen al tientallen jaren bekend. De meeste grondstoffen voor voedingsmiddelen komen uit de akker- en tuinbouw, de veehouderij en de visserij. Besmetting vindt daar plaats met micro-organismen afkomstig uit grond, fecaliën, water,

  10. Control of Listeria monocytogenes on vacuum-packaged frankfurters sprayed with lactic acid alone or in combination with sodium lauryl sulfate.

    Science.gov (United States)

    Byelashov, Oleksandr A; Kendall, Patricia A; Belk, Keith E; Scanga, John A; Sofos, John N

    2008-04-01

    U.S. regulations require that processors employ lethal or inhibitory antimicrobial alternatives in production of ready-to-eat meat and poultry products that support growth of Listeria monocytogenes and may be exposed to the processing environment after a lethality treatment. In this study, lactic acid (LA; 5%, vol/vol) and sodium lauryl sulfate (SLS; 0.5%, wt/vol) were evaluated individually or as a mixture (LASLS) for control of L. monocytogenes on frankfurters. Frankfurters were inoculated with a 10-strain mixture of L. monocytogenes, sprayed for 10 s (20 bar, 23 +/- 2 degrees C) with antimicrobials or distilled water (DW) before (LASLS or DW) or after (LA, SLS, LASLS, or DW) inoculation (4.8 +/- 0.1 log CFU/cm2), vacuum packaged, and stored at 4 degrees C for 90 days. Samples were analyzed for numbers of the pathogen (on PALCAM agar) and for total microbial counts (on tryptic soy agar with yeast extract) during storage. Spraying with DW, LA, or SLS after inoculation reduced numbers of L. monocytogenes by 1.3 +/- 0.2, 1.8 +/- 0.5, and 2.0 +/- 0.4 log CFU/cm2, respectively. The LASLS mixture applied before or after inoculation reduced pathogen populations by 1.8 +/- 0.4 and 2.8 +/- 0.2 log CFU/cm2, respectively. No further reduction by any treatment was observed during storage. The bacterial growth curves (fitted by the model of Baranyi and Roberts) indicated that the lag-phase duration of the bacterium on control samples (13.85 to 15.18 days) was extended by spraying with all solutions containing LA. For example, LA suppressed growth of L. monocytogenes for 39.14 to 41.01 days. Pathogen growth rates also were lower on frankfurters sprayed after inoculation with LA or LASLS compared to those sprayed with DW. Therefore, spraying frankfurters with a mixture of LA and SLS may be a useful antilisterial alternative treatment for ready-to-eat meat and poultry products.

  11. Combined effect of gamma radiation and heating on the destruction of Listeria monocytogenes and Salmonella typhimurium in cook-chill roast beef and gravy.

    Science.gov (United States)

    Grant, I R; Patterson, M F

    1995-10-01

    The effect of heating alone (60, 65 or 70 degrees C), heating after irradiation (0.8 kGy) and heating after irradiation and storage for 14 days at 2-3 degrees C on the destruction of Listeria monocytogenes and Salmonella typhimurium in artifically inoculated minced cook-chill roast beef and gravy was investigated. Inoculated minced roast beef samples (5 g) were heated in Stomacher bags completely immersed in a water bath at each of the test temperatures. Survivors were enumerated and D and z values were determined for each of the pathogens. Observed thermal D values for two strains of L. monocytogenes at 60, 65 and 70 degrees C in the absence of pre-irradiation were 90.0-97.5 s, 34.0-53.0 s and 22.4-28.0 s, respectively, whereas thermal D values after pre-irradiation were 44.0-46.4 s, 15.3-16.8 s and 5.5-7.8 s at 60, 65 and 70 degrees C, respectively. This reduction in D values provides evidence for radiation-induced heat-sensitisation in L. monocytogenes. There was some evidence of heat-sensitisation of S. typhimurium at 60 degrees C, but not at either 65 or 70 degrees C. The z value also decreased as a consequence of pre-irradiation to a dose of 0.8 kGy (11.0-12.7 degrees C). The radiation-induced heat-sensitivity in L. monocytogenes was found to persist for up to 2 weeks storage at 2-3 degrees C prior to heating. As cook-chill products are intended to be reheated prior to consumption the results of the present study suggest that any L. monocytogenes present in a cook-chill product would be more easily killed during reheating if it were to be treated with a low dose of gamma radiation during manufacture.

  12. Detection of Listeria monocytogenes from selective enrichment broth using MALDI-TOF Mass Spectrometry.

    Science.gov (United States)

    Jadhav, Snehal; Sevior, Danielle; Bhave, Mrinal; Palombo, Enzo A

    2014-01-31

    Conventional methods used for primary detection of Listeria monocytogenes from foods and subsequent confirmation of presumptive positive samples involve prolonged incubation and biochemical testing which generally require four to five days to obtain a result. In the current study, a simple and rapid proteomics-based MALDI-TOF MS approach was developed to detect L. monocytogenes directly from selective enrichment broths. Milk samples spiked with single species and multiple species cultures were incubated in a selective enrichment broth for 24h, followed by an additional 6h secondary enrichment. As few as 1 colony-forming unit (cfu) of L. monocytogenes per mL of initial selective broth culture could be detected within 30h. On applying the same approach to solid foods previously implicated in listeriosis, namely chicken pâté, cantaloupe and Camembert cheese, detection was achieved within the same time interval at inoculation levels of 10cfu/mL. Unlike the routine application of MALDI-TOF MS for identification of bacteria from solid media, this study proposes a cost-effective and time-saving detection scheme for direct identification of L. monocytogenes from broth cultures.This article is part of a Special Issue entitled: Trends in Microbial Proteomics. Globally, foodborne diseases are major causes of illness and fatalities in humans. Hence, there is a continual need for reliable and rapid means for pathogen detection from food samples. Recent applications of MALDI-TOF MS for diagnostic microbiology focused on detection of microbes from clinical specimens. However, the current study has emphasized its use as a tool for detecting the major foodborne pathogen, Listeria monocytogenes, directly from selective enrichment broths. This proof-of-concept study proposes a detection scheme that is more rapid and simple compared to conventional methods of Listeria detection. Very low levels of the pathogen could be identified from different food samples post-enrichment in

  13. Adaptive Response of Listeria monocytogenes to Heat, Salinity and Low pH, after Habituation on Cherry Tomatoes and Lettuce Leaves.

    Science.gov (United States)

    Poimenidou, Sofia V; Chatzithoma, Danai-Natalia; Nychas, George-John; Skandamis, Panagiotis N

    2016-01-01

    Pathogens found on fresh produce may encounter low temperatures, high acidity and limited nutrient availability. The aim of this study was to evaluate the effect of habituation of Listeria monocytogenes on cherry tomatoes or lettuce leaves on its subsequent response to inhibitory levels of acid, osmotic and heat stress. Habituation was performed by inoculating lettuce coupons, whole cherry tomatoes or tryptic soy broth (TSB) with a three-strains composite of L. monocytogenes, which were further incubated at 5°C for 24 hours or 5 days. Additionally, cells grown overnight in TSB supplemented with 0.6% yeast extract (TSBYE) at 30°C were used as control cells. Following habituation, L. monocytogenes cells were harvested and exposed to: (i) pH 3.5 adjusted with lactic acid, acetic acid or hydrochloric acid (HCl), and pH 1.5 (HCl) for 6 h; (ii) 20% NaCl and (iii) 60°C for 150 s. Results showed that tomato-habituated L. monocytogenes cells were more tolerant (P lettuce, and habituation on both foods resulted in more stress resistant cells than prior growth in TSB. On the contrary, the highest resistance to heat stress (P lettuce-habituated L. monocytogenes cells followed by TSB-grown cells at 5°C for 24 h, whereas tomato-habituated cells were highly sensitized. Prolonged starvation on fresh produce (5 days vs. 24 h) increased resistance to osmotic and acid stress, but reduced thermotolerance, regardless of the pre-exposure environment (i.e., tomatoes, lettuce or TSB). These results indicate that L. monocytogenes cells habituated on fresh produce at low temperatures might acquire resistance to subsequent antimicrobial treatments raising important food safety implications.

  14. Sensitivity to acetic acid, ability to colonize abiotic surfaces and virulence potential of Listeria monocytogenes EGD-e after incubation on parsley leaves.

    Science.gov (United States)

    Rieu, A; Guzzo, J; Piveteau, P

    2010-02-01

    To investigate how the survival of Listeria monocytogenes on parsley leaves may affect its ability to sustain process-related harsh conditions and its virulence. Parsley seedlings were spot inoculated with stationary phase cells of L. monocytogenes EGD-e and incubated for 15 days. Each day, bacterial cells were harvested and enumerated, and their ability to survive acetic acid challenge (90 min, pH 4.0), to colonize abiotic surfaces and to grow as biofilms was assessed. After a 3-log decrease over the first 48 h, the population stabilized to about 10(6) CFU g(-1) until the sixth day. After the sixth day, L. monocytogenes was no longer detected, even after specific enrichment. Incubation on parsley leaves affected the ability of L. monocytogenes to survive acetic acid challenge (90 min, pH 4.0) and to adhere to stainless steel although the ability to grow as biofilm was preserved. To further investigate these physiological alterations, the mRNA levels of six target genes (bsh, clpC, groEL, inlA, opuC, prfA) was quantified using reverse transcription qPCR after 5 h of incubation on parsley leaves. A decrease was observed in all but one (bsh) target, including groEL and clpC which are involved in resistance to salt and acid. Moreover, the decrease in the levels of inlA, prfA and opuC transcripts after incubation on parsley suggested a repression of some genes involved in pathogenicity. In vitro assessment of mammalian cell adherence and invasion using Caco-2 cells confirmed the repression of the virulence factor InlA; however, the virulence potential in vivo in the chick embryo model was not affected. Listeria monocytogenes did undergo rapid changes to adapt its physiology to the phyllosphere. This study highlights the physiological changes undergone by L. monocytogenes during/after survival on parsley leaves.

  15. Inoculation of sugarcane with diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Nivaldo Schultz

    2014-04-01

    Full Text Available The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer. The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

  16. Seeding Stress Resilience through Inoculation

    Directory of Open Access Journals (Sweden)

    Archana Ashokan

    2016-01-01

    Full Text Available Stress is a generalized set of physiological and psychological responses observed when an organism is placed under challenging circumstances. The stress response allows organisms to reattain the equilibrium in face of perturbations. Unfortunately, chronic and/or traumatic exposure to stress frequently overwhelms coping ability of an individual. This is manifested as symptoms affecting emotions and cognition in stress-related mental disorders. Thus environmental interventions that promote resilience in face of stress have much clinical relevance. Focus of the bulk of relevant neurobiological research at present remains on negative aspects of health and psychological outcomes of stress exposure. Yet exposure to the stress itself can promote resilience to subsequent stressful episodes later in the life. This is especially true if the prior stress occurs early in life, is mild in its magnitude, and is controllable by the individual. This articulation has been referred to as “stress inoculation,” reminiscent of resilience to the pathology generated through vaccination by attenuated pathogen itself. Using experimental evidence from animal models, this review explores relationship between nature of the “inoculum” stress and subsequent psychological resilience.

  17. Synthesis and properties of novel 4,5-diaminonaphthalimides

    International Nuclear Information System (INIS)

    Morris, I.P.

    1999-07-01

    This thesis presents work carried out into the synthesis and properties of Novel 4,5-diaminonaphthalimides. Previous work had identified that these compounds could be synthesised through a short reaction sequence but a very limited number of examples had been produced. With some modifications, the structure of 4,5-diaminonaphthalimides suggests a number of applications. The diamine functionality suggests the formation of complexes and if chiral amines were used asymmetric synthesis is a possibility. Naphthalimides are known to intercalate into DNA and so compounds of this nature may have interesting anti-cancer activity. Finally diaminonaphthalimides are strongly fluorescent and this in combination with the chelation potential of the diamine functionality may afford ion and molecular sensors. The first section of this thesis reviews these areas of research and demonstrates how diaminonaphthalimides might contribute to these areas. The second section describes the synthesis of 4,5-diaminonaphthalimides and illustrates the variety of compounds that may be synthesised. In addition this section explores the applications to fluorescence sensing and asymmetric synthesis. 4,5-Diaminonaphthalimides are shown to undergo chelation enhanced quenching (CHEQ) and chelation enhanced fluorescence (CHEF) with various transition metal ions. The precise features are shown to be dependent on the metal ion present. The mass spectroscopic results discussed in this section show 4,5-diaminonaphthalimides to be a new class of supramolecular compound as they show pre-assembly around alkali earth metal ions. 4,5-Diaminonaphthalimides were also used as catalysts in asymmetric reactions where they show some catalytic activity in the addition of diethylzinc to benzaldehyde. (author)

  18. Novel Cadmium Resistance Determinant in Listeria monocytogenes.

    Science.gov (United States)

    Parsons, Cameron; Lee, Sangmi; Jayeola, Victor; Kathariou, Sophia

    2017-03-01

    Listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables Listeria to tolerate exposure to cadmium is the cadAC efflux system, with CadA being a P-type ATPase. Three different cadA genes (designated cadA1 to cadA3 ) were previously characterized in L. monocytogenes A novel putative cadmium resistance gene ( cadA4 ) was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking. In this study, we characterized cadA4 in L. monocytogenes strain F8027, a cadmium-resistant strain of serotype 4b. By screening a mariner-based transposon library of this strain, we identified a mutant with reduced tolerance to cadmium and that harbored a single transposon insertion in cadA4 The tolerance to cadmium was restored by genetic complementation with the cadmium resistance cassette ( cadA4C ), and enhanced cadmium tolerance was conferred to two unrelated cadmium-sensitive strains via heterologous complementation with cadA4C Cadmium exposure induced cadA4 expression, even at noninhibitory levels. Virulence assessments in the Galleria mellonella model suggested that a functional cadA4 suppressed virulence, potentially promoting commensal colonization of the insect larvae. Biofilm assays suggested that cadA4 inactivation reduced biofilm formation. These data not only confirm cadA4 as a novel cadmium resistance determinant in L. monocytogenes but also provide evidence for roles in virulence and biofilm formation. IMPORTANCE Listeria monocytogenes is an intracellular foodborne pathogen causing the disease listeriosis, which is responsible for numerous hospitalizations and deaths every year. Among the adaptations that enable the survival of Listeria in the environment are the abilities to persist in biofilms, grow in the cold, and

  19. The Efficiency of UVC Radiation in the Inactivation of Listeria monocytogenes on Beef-Agar Food Models

    Directory of Open Access Journals (Sweden)

    Christian James

    2015-01-01

    Full Text Available The aim of this study is to evaluate the eff ect of meat content and surface smoothness on the deactivation of Listeria monocytogenes in beef-agar food models achieved by shortwave ultraviolet (UVC light. Food models with various meat contents were made using chopped beef slices and agar solution. Prepared models together with a Listeria selective agar (LSA plate and a slice of cooked beef were inoculated with L. monocytogenes and then exposed to UVC light. Population of Listeria reduced to below the level of detection on the LSA plates. As the content of beef in the beef-agar models increased, more L. monocytogenes cells survived. Survival was greatest on the treated cooked slice of beef. To bett er understand the effect of surface irregularities, a white light interferometer was used to analyse the surface smoothness of beef-agar media and LSA plates. No correlation was observed between the surface roughness of seven out of nine types of produced beef-agar media and the degree of inactivation resulting from UVC radiation at the given dose, whereas, less bacterial cells were killed as beef content of the food models increased. The findings of the current study show that the chemical composition of the treated sample also plays an important role in pathogen resistance and survival, meaning that two samples with similar surface irregularities but diff erent chemical composition might produce very diff erent inactivation results when exposed to UVC light.

  20. Survival of Listeria monocytogenes on fresh blueberries (Vaccinium corymbosum) stored under controlled atmosphere and ozone.

    Science.gov (United States)

    Concha-Meyer, Anibal; Eifert, Joseph; Williams, Robert; Marcy, Joseph; Welbaum, Gregory

    2014-05-01

    Listeria monocytogenes is a foodborne pathogen that represents a high risk for consumers because it can grow under refrigeration conditions and can also develop acid tolerance. Fresh blueberries are hand-picked, packed, and transported under refrigeration without receiving a microbial inactivation treatment. The aim of this work was to study the survival of L. monocytogenes in fresh highbush blueberries stored at 4 or 12 °C under different controlled atmosphere conditions, including air (control); 5% O2, 15% CO2, 80% N2 (controlled atmosphere storage [CAS]); or ozone gas (O3), 4 ppm at 4 °C or 2.5 ppm at 12 °C, at high relative humidity (90 to 95%) for a total of 10 days. Fresh blueberries inside a plastic clamshell were spot inoculated with the bacteria and were stored at 4 or 12 °C in isolated cabinets under air, CAS, and O3 atmospheric conditions. Samples were evaluated on days 0, 1, 4, 7, and 10 for microbial growth using modified Oxford agar. CAS did not delay or inhibit L. monocytogenes growth in fresh blueberries after 10 days. O3 achieved 3- and 2-log reductions when compared with air treatment at 4 and 12 °C, respectively. Low concentrations of O3 together with proper refrigeration temperature can ensure product safety throughout transportation. O3 is a strong antimicrobial that safely decomposes to oxygen and water without leaving residues and can be used as an alternative method to prevent bacterial growth during a long transport period.

  1. Identifying ingredients that delay outgrowth of Listeria monocytogenes in natural, organic, and clean-label ready-to-eat meat and poultry products.

    Science.gov (United States)

    McDonnell, Lindsey M; Glass, Kathleen A; Sindelar, Jeffrey J

    2013-08-01

    The objective of this study was to identify ingredients that inhibit Listeria monocytogenes in natural, organic, or clean-label ready-to-eat meat and poultry products. Fourteen ingredients were screened in uncured (no-nitrate-or-nitrite-added), traditional-cured (156 ppm of purified sodium nitrite), cultured (alternative cured, natural nitrate source, and Staphylococcus carnosus), or preconverted (alternative cured, natural nitrite source) turkey slurries. Slurries were cooked, cooled, inoculated to yield 3 log CFU/ml L. monocytogenes, stored at 4°C, and tested weekly for 4 weeks. Three antimicrobial ingredients, 1.5 % vinegar-lemon-cherry powder blend, 2.5 % buffered vinegar, and 3.0 % cultured sugar-vinegar blend, were incorporated into alternative-cured ham and uncured roast beef and deli-style turkey breast. Controls included all three meat products without antimicrobial ingredients and a traditional-cured ham with 2.8 % sodium lactate-diacetate. Cooked, sliced products were inoculated with 3 log CFU/g L. monocytogenes, vacuum packed, and stored at 4 or 7°C, for up to 12 weeks. For control products without antimicrobial agents stored at 4°C, a 2-log L. monocytogenes increase was observed at 2 weeks for ham and turkey and at 4 weeks for roast beef. Growth (>1-log increase) in the sodium lactate-diacetate was delayed until week 6. Compared with the control, the addition of either vinegar-lemon-cherry powder blend or buffered vinegar delayed L. monocytogenes growth for an additional 2 weeks, while the addition of cultured sugar-vinegar blend delayed growth for an additional 4 weeks for both ham and turkey. The greatest L. monocytogenes delay was observed in roast beef containing any of the three antimicrobial ingredients, with no growth detected through 12 weeks at 4°C for all the treatments. As expected, L. monocytogenes grew substantially faster in products stored at 7°C than at 4°C. These data suggest that antimicrobial ingredients from a natural source

  2. Thermal conductivity of Cu–4.5 Ti alloy

    Indian Academy of Sciences (India)

    The thermal conductivity (TC) of peak aged Cu–4.5 wt% Ti alloy was measured at different temperatures and studied its variation with temperature. It was found that TC increased with increasing temperature. Phonon and electronic components of thermal conductivity were computed from the results. The alloy exhibits an ...

  3. Impact of dilution ratios on Listeria monocytogenes growth during University of Vermont medium enrichment of deli meats.

    Science.gov (United States)

    Zhang, Lei; Yan, Zhinong; Ryser, Elliot T

    2007-11-01

    In the U.S. Department of Agriculture (USDA) method for Listeria detection, a 25-g composite food sample is enriched in 225 ml of University of Vermont medium (UVM), giving a detection limit of 0.04 CFU/g. However, in a recent large-scale four-state deli meat survey for L. monocytogenes, 125-g samples enriched in 1,125 ml of UVM were requested to increase the detection limit to 0.008 CFU/g. To circumvent problems associated with large volumes of UVM, the impact on L. monocytogenes growth of lower dilution ratios used for enrichment and most-probable-number (MPN) detection was compared with the results obtained using the conventional 1:10 dilution. In this study, 125-g samples of cured turkey, uncured turkey, ham, and roast beef were inoculated with a six-strain L. monocytogenes cocktail to contain approximately 1 x 10(3) CFU/g. This cocktail was then diluted 1:3, 1:5, or 1:10 in UVM, homogenized, enriched at 30 degrees C, and periodically plated on modified Oxford agar to determine generation times during 24 h of incubation. The same enrichment protocol was also assessed in a three-tube MPN assay using 125-g samples inoculated with L. monocytogenes to contain approximately 1 CFU/g. The effects of two homogenization methods, stomaching and pulsifying, on Listeria growth were compared using oven-roasted turkey breast diluted 1:3, 1:5, and 1:10 in UVM. Overall, the growth rates, generation times, and MPN values for each of the four selected deli meats were similar (P > 0.05) using UVM enrichment ratios of 1:3, 1:5, and 1:10, with no significant (P > 0.05) differences in L. monocytogenes growth rate or generation time between experiments using pulsifying and stomaching. These findings indicate that lower volumes of UVM can be used in the USDA procedure when examining deli meats without compromising Listeria recovery.

  4. Heat treatment effects on tensile properties of V-(4-5) wt.% Cr-(4-5) wt.% Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppet, W.K. [Argonne National Lab., IL (United States)

    1997-08-01

    Effects of thermomechanical treatments on microstructures and mechanical properties are of interest for long term application of V-Cr-Ti alloys in fusion reactor systems. Influence of thermal annealing at 1050{degrees}C on stress/strain behavior, maximum engineering strength, and uniform and total elongation were evaluated. The results show that multiple annealing has minimal effect on the tensile properties of V-(4-5)Cr-(4-5)Ti alloys tested at room temperature and at 500{degrees}C.

  5. Spray method for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes.

    Science.gov (United States)

    Back, Kyeong-Hwan; Kim, Sang-Oh; Park, Ki-Hwan; Chung, Myung-Sub; Kang, Dong-Hyun

    2012-10-01

    Selective agar is inadequate for supporting recovery of injured cells. During risk assessment of certain foods, both injured and noninjured cells must be enumerated. In this study, a new method (agar spray method) for recovering sublethally heat-injured microorganisms was developed and used for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes. Molten selective agar was applied as an overlay to presolidified nonselective tryptic soy agar (TSA) by spray application. Heat-injured cells (55°C for 10 min in 0.1% peptone water or 55°C for 15 min in sterilized skim milk) were inoculated directly onto solidified TSA. After a 2-h incubation period for cell repair, selective agar was applied to the TSA surface with a sprayer, and the plates were incubated. The recovery rate for heat-injured Salmonella Typhimurium and L. monocytogenes with the spray method was compared with the corresponding rates associated with TSA alone, selective media alone, and the conventional overlay method (selective agar poured on top of resuscitated cells grown on TSA and incubated for 2 h). No significant differences (P > 0.05) were found in pathogen recovery obtained with TSA, the overlay method, and the spray method. However, a lower recovery rate (P recovery and detection of injured cells.

  6. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging

    Directory of Open Access Journals (Sweden)

    Laura N. Sandoval

    2016-04-01

    Full Text Available A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.

  7. Evaluation of aqueous and alcohol-based quaternary ammonium sanitizers for inactivating Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes on peanut and pistachio shells.

    Science.gov (United States)

    McEgan, Rachel; Danyluk, Michelle D

    2015-05-01

    This study evaluated the efficacy of aqueous (aQUAT) and isopropyl alcohol-based quaternary ammonium (ipQUAT) sanitizers for reducing Salmonella spp., Escherichia coli O157:H7, or Listeria monocytogenes populations on peanut and pistachio shell pieces. Inoculated nutshells were mixed with QUAT sanitizers, water, or 70% ethanol and enumerated immediately or after incubation at 30 °C for 48 h. None of the treatments had any immediate effect on Salmonella or E. coli O157:H7 populations on the peanut or pistachio shells. L. monocytogenes populations declined immediately on the peanut and pistachio shells treated with aQUAT or ipQUAT. After incubation, Salmonella and E. coli O157:H7 populations increased significantly on the water- or aQUAT-treated peanut and pistachio shells. L. monocytogenes populations also increased significantly on the water- or aQUAT-treated peanut shells, but levels did not change on the water-treated pistachio shells and levels were just above the limit of detection on the aQUAT-treated pistachio shells. After treatment with ipQUAT and 48-h incubation, Salmonella and E. coli O157:H7 populations decreased to or below the limit of detection on both shell types; L. monocytogenes populations remained at or below the limit of detection on both shell types. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Simultaneous Detection of Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes at a Very Low Level Using Simultaneous Enrichment Broth and Multichannel SPR Biosensor.

    Science.gov (United States)

    Zhang, Xiaoguang; Tsuji, Sachiko; Kitaoka, Hayato; Kobayashi, Hiroshi; Tamai, Mitsuru; Honjoh, Ken-Ichi; Miyamoto, Takahisa

    2017-10-01

    Detection of foodborne pathogens at very low levels is still a challenge. A custom-built multichannel surface plasmon resonance (SPR) biosensor and simultaneous enrichment broth (SEB) were used to develop a simultaneous detection method for 3 important foodborne pathogens, Escherichia coli O157:H7 (O157:H7), Salmonella enteritidis, and Listeria monocytogenes, at a very low level. These 3 foodborne pathogens at a very low level (14, 6, and 28 CFU/25 g (mL) for O157:H7, S. enteritidis, and L. monocytogenes, respectively) were inoculated in SEB and incubated at 37 ˚C for 24 h. Sample prepared from the simultaneous enrichment culture was analyzed using the multichannel SPR biosensor and sensor chip immobilized with polyclonal antibodies specific to each of the target pathogens. O157:H7, S. enteritidis, and L. monocytogenes in chicken were detected simultaneously at an inoculum dose of 14, 6, and 28 CFU/25 g, respectively. Our method using a custom-built multichannel SPR biosensor and enrichment in SEB is expected as a rapid and simultaneous detection method for low levels of O157:H7, S. enteritidis, and L. monocytogenes in food. Our method is expected as a rapid and simultaneous detection method for pathogens at very low levels. It has great potential for safety control of food and microbiological detection applications. © 2017 Institute of Food Technologists®.

  9. Recombinant phage probes for Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Carnazza, S; Gioffre, G; Felici, F; Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

    2007-10-03

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 10{sup 4} cells ml{sup -1}. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  10. Recombinant phage probes for Listeria monocytogenes

    Science.gov (United States)

    Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

    2007-10-01

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  11. Klebsiella pneumoniae inoculants for enhancing plant growth

    Science.gov (United States)

    Triplett, Eric W [Middleton, WI; Kaeppler, Shawn M [Oregon, WI; Chelius, Marisa K [Greeley, CO

    2008-07-01

    A biological inoculant for enhancing the growth of plants is disclosed. The inoculant includes the bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101, Pantoea agglomerans P102, Klebsiella pneumoniae 342, Klebsiella pneumoniae zmvsy, Herbaspirillum seropedicae Z152, Gluconacetobacter diazotrophicus PA15, with or without a carrier. The inoculant also includes strains of the bacterium Pantoea agglomerans and K. pneumoniae which are able to enhance the growth of cereal grasses. Also disclosed are the novel bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101 and P102, and Klebsiella pneumoniae 342 and zmvsy.

  12. Inhibition of Listeria monocytogenes on cooked cured chicken breasts by acidified coating containing allyl isothiocyanate or deodorized Oriental mustard extract.

    Science.gov (United States)

    Olaimat, Amin N; Holley, Richard A

    2016-08-01

    Ready-to-eat meats are considered foods at high risk to cause life-threatening Listeria monocytogenes infections. This study screened 5 L. monocytogenes strains for their ability to hydrolyze sinigrin (a glucosinolate in Oriental mustard), which formed allyl isothiocyanate (AITC) and reduced L. monocytogenes viability on inoculated vacuum-packed, cooked, cured roast chicken slices at 4 °C. Tests involved incorporation of 25-50 μl/g AITC directly or 100-250 mg/g Oriental mustard extract in 0.5% (w/v) κ-carrageenan/2% (w/v) chitosan-based coatings prepared using 1.5% malic or acetic acid. L. monocytogenes strains hydrolyzed 33.6%-48.4% pure sinigrin in MH broth by 21 d at 25 °C. Acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 100-250 mg/g mustard reduced the viability of L. monocytogenes and aerobic bacteria on cooked, cured roast chicken slices by 4.1 to >7.0 log10 CFU/g compared to uncoated chicken stored at 4 °C for 70 d. Coatings containing malic acid were significantly more antimicrobial than those with acetic acid. During storage for 70 d, acidified κ-carrageenan/chitosan coatings containing 25-50 μl/g AITC or 250 mg/g mustard extract reduced lactic acid bacteria (LAB) numbers 3.8 to 5.4 log10 CFU/g on chicken slices compared to uncoated samples. Acidified κ-carrageenan/chitosan-based coatings containing either AITC or Oriental mustard extract at the concentrations tested had the ability to control L. monocytogenes viability and delay growth of potential spoilage bacteria on refrigerated, vacuum-packed cured roast chicken. Copyright © 2016. Published by Elsevier Ltd.

  13. Variations in biofilm formation, desiccation resistance and Benzalkonium chloride susceptibility among Listeria monocytogenes strains isolated in Canada

    DEFF Research Database (Denmark)

    Piercey, Marta J.; C. Ells, Timothy; Macintosh, Andrew J.

    2017-01-01

    needed to inhibit the formation of biofilm by LGI1/CC8 strains during incubation for 48 h and 6 days compared to other strains. Formation of biofilm on stainless steel was not significantly (p > 0.05) different among the strains. Analysis of genetic sequence data from desiccation and BAC sensitive (CP4 5......Listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. Survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure....... The objectives of this research were to compare 14 L. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (BAC) sensitivity, desiccation resistance, and ability to form biofilm. Correlations were tested between those responses, and the presence...

  14. Acute Fetal Demise with First Trimester Maternal Infection Resulting from Listeria monocytogenes in a Nonhuman Primate Model

    Science.gov (United States)

    Wolfe, Bryce; Wiepz, Gregory J.; Schotzko, Michele; Bondarenko, Gennadiy I.; Durning, Maureen; Simmons, Heather A.; Mejia, Andres; Faith, Nancy G.; Sampene, Emmanuel; Suresh, Marulasiddappa; Kathariou, Sophia; Czuprynski, Charles J.

    2017-01-01

    ABSTRACT Infection with Listeria monocytogenes during pregnancy is associated with miscarriage, preterm birth, and neonatal complications, including sepsis and meningitis. While the risk of these conditions is thought to be greatest during the third trimester of pregnancy, the determinants of fetoplacental susceptibility to infection, the contribution of gestational age, and the in vivo progression of disease at the maternal-fetal interface are poorly understood. We developed a nonhuman primate model of listeriosis to better understand antecedents of adverse pregnancy outcomes in early pregnancy. Four pregnant cynomolgus macaques (Macaca fascicularis) received a single intragastric inoculation between days 36 and 46 of gestation with 107 CFU of an L. monocytogenes strain isolated from a previous cluster of human listeriosis cases that resulted in adverse pregnancy outcomes. Fecal shedding, maternal bacteremia, and fetal demise were consistently noted within 7 to 13 days. Biopsy specimens of maternal liver, spleen, and lymph node displayed variable inflammation and relatively low bacterial burden. In comparison, we observed greater bacterial burden in the decidua and placenta and the highest burden in fetal tissues. Histopathology indicated vasculitis, fibrinoid necrosis, and thrombosis of the decidual spiral arteries, acute chorioamnionitis and villitis in the placenta, and hematogenous infection of the fetus. Vascular pathology suggests early impact of L. monocytogenes infection on spiral arteries in the decidua, which we hypothesize precipitates subsequent placentitis and fetal demise. These results demonstrate that L. monocytogenes tropism for the maternal reproductive tract results in infection of the decidua, placenta, and the fetus itself during the first trimester of pregnancy. PMID:28223455

  15. Survival strategies of Listeria monocytogenes - roles of regulators and transporters

    NARCIS (Netherlands)

    Wemekamp-Kamphuis, H.H.

    2003-01-01

    Outbreaks of the food-borne pathogen Listeria monocytogenes are mainly associated with ready-to-eatfoods. Survival strategies of L. monocytogenes in relation to minimally processed foods were studied.

  16. Incidence and control of Listeria monocytogenes in foods in Denmark

    DEFF Research Database (Denmark)

    Nørrung, Birgit; Andersen, Jens Kirk; Schlundt, Jørgen

    1999-01-01

    The Danish regulatory policy on Listeria monocytogenes in foods is based on the principles of HACCP and was developed using a health risk assessment approach. The Danish policy focuses examinations and criteria for L. monocytogenes in ready-to-eat foods and is based on a combination of inspection...

  17. Listeria monocytogenes internalizes in Romaine Lettuce grown in greenhouse conditions

    Science.gov (United States)

    Listeria monocytogenes has been implicated in a number of outbreaks involving fresh produce, including an outbreak in 2016 resulting from contaminated packaged salads. The persistence and internalization potential of L. monocytogenes in romaine lettuce was evaluated, and the persistence of two L. mo...

  18. Occurrence of Listeria monocytogenes in smoked fish in Sokoto ...

    African Journals Online (AJOL)

    The present study was conducted to determine the prevalence of Listeria monocytogenes in smoked fish in Sokoto, Nigeria. A total of 115 different species of smoked fish from the various retail outlets and market places within the metropolis were analysed for the presence of L. monocytogenes using ISO culture method.

  19. Detection of Listeria Spp. and Listeria monocytogenes in vegetables ...

    African Journals Online (AJOL)

    This paper aimed to study the prevalence and antibiotic resistance pattern among Listeria monocytogenes in raw vegetables sourced from commercial farms and local farms in Terengganu. Thirteen types of vegetables investigated for the presence of L. monocytogenes using multiplex PCR and LAMP methods. Isolation of ...

  20. Genome sequences of Listeria monocytogenes strains with resistance to arsenic

    Science.gov (United States)

    Listeria monocytogenes frequently exhibits resistance to arsenic. We report here the draft genome sequences of eight genetically diverse arsenic-resistant L. monocytogenes strains from human listeriosis and food-associated environments. Availability of these genomes would help to elucidate the role ...

  1. Listeria monocytogenes growth limits and stress resistance mechanisms

    NARCIS (Netherlands)

    Veen, van der S.

    2008-01-01

    The food-borne pathogen Listeria monocytogenes is a Gram-positive facultative anaerobic rod, which is the causative agent of listeriosis. Due to the severity of the disease and the fact that its incidence is increasing in numerous European countries, L. monocytogenes is of great public health

  2. Resistance of Listeria monocytogenes biofilms to sanitizing agents

    Science.gov (United States)

    Listeria monocytogenes is notorious for its capacity to colonize the environment and equipment of food processing facilities and to persist in the processing plant ecosystem, sometimes for decades. Such persistence is mediated by multiple attributes of L. monocytogenes, including the pathogen’s capa...

  3. Effects of prebiotics on the infective potential of Listeria monocytogenes

    DEFF Research Database (Denmark)

    Ebersbach, Tine

    % xylooligosaccharides (XOS), galactooligosaccharides (GOS), inulin, apple pectin or polydextrose for three weeks before oral challenge with L. monocytogenes. XOS and GOS significantly improved resistance of guinea pigs to L. monocytogenes, while inulin and apple pectin decreased the resistance. No significant effect...

  4. Monitoring paneer for Listeria monocytogenes - A high risk food ...

    African Journals Online (AJOL)

    A multiplex polymerase chain reaction (PCR) assay was developed and applied to spiked and natural paneer samples to detect Listeria monocytogenes, a high risk food pathogen. The sensitivity of the assay on L. monocytogenes spiked paneer samples was 104 cells prior to enrichment, was improved to 103 cells after 4 h ...

  5. New inoculants on maize silage fermentation

    Directory of Open Access Journals (Sweden)

    Fábia Giovana do Val de Assis

    2014-08-01

    Full Text Available The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1 of forage for each strain of lactic acid bacteria (LAB identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, water-soluble carbohydrates (WSC, organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT and aerobic stability (AS, was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.

  6. Evaluation of two loop-mediated isothermal amplification methods for the detection of Salmonella Enteritidis and Listeria monocytogenes in artificially contaminated ready-to-eat fresh products

    Directory of Open Access Journals (Sweden)

    Angeliki Birmpa

    2015-08-01

    Full Text Available In the present study, the effectiveness of two loop-mediated isothermal amplification (LAMP assays was evaluated. Samples of romaine lettuce, strawberries, cherry tomatoes, green onions and sour berries were inoculated with known dilutions (100-108 CFU/g of produce of S. Enteritidis and L. monocytogenes. With LAMP assay, pathogens can be detected in less than 60 min. The limits of detection of S. Enteritidis and L. monocytogenes depended on the food sample tested and on the presence of enrichment step. After enrichment steps, all food samples were found positive even at low initial pathogen levels. The developed LAMP, assays, are expected to become a valuable, robust, innovative, powerful, cheap and fast monitoring tool, which can be extensively used for routine analysis, and screening of contaminated foods by the food industry and the Public Food Health Authorities.

  7. Phosphorylation of inositol 1,4,5-trisphosphate analogues by 3-kinase and dephosphorylation of inositol 1,3,4,5-tetrakisphosphate analogues by 5-phosphatase

    NARCIS (Netherlands)

    Dijken, Peter van; Lammers, Aleida A.; Ozaki, Shoichiro; Potter, Barry V.L.; Erneux, Christophe; Haastert, Peter J.M. van

    1994-01-01

    A series of P-32-labeled D-myo-inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P-4] analogues was enzymically prepared from the corresponding D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P-3] analogues using recombinant rat brain Ins(1,4,5)P-3 3-kinase and [gamma-P-32]ATP. Ins(1,4,5)P-3 analogues

  8. OpenMP 4.5 Validation and Verification Suite

    Energy Technology Data Exchange (ETDEWEB)

    2017-12-15

    OpenMP, a directive-based programming API, introduce directives for accelerator devices that programmers are starting to use more frequently in production codes. To make sure OpenMP directives work correctly across architectures, it is critical to have a mechanism that tests for an implementation's conformance to the OpenMP standard. This testing process can uncover ambiguities in the OpenMP specification, which helps compiler developers and users make a better use of the standard. We fill this gap through our validation and verification test suite that focuses on the offload directives available in OpenMP 4.5.

  9. Evaluation of near-infrared pasteurization in controlling Escherichia coli O157:H7, Salmonella enterica serovar typhimurium, and Listeria monocytogenes in ready-to-eat sliced ham.

    Science.gov (United States)

    Ha, Jae-Won; Ryu, Sang-Ryeol; Kang, Dong-Hyun

    2012-09-01

    This study was conducted to investigate the efficacy of near-infrared (NIR) heating to reduce Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes in ready-to-eat (RTE) sliced ham compared to conventional convective heating, and the effect of NIR heating on quality was determined by measuring the color and texture change. A cocktail of three pathogens was inoculated on the exposed or protected surfaces of ham slices, followed by NIR or conventional heating at 1.8 kW. NIR heating for 50 s achieved 4.1-, 4.19-, and 3.38-log reductions in surface-inoculated S. Typhimurium, E. coli O157:H7, and L. monocytogenes, respectively, whereas convective heating needed 180 s to attain comparable reductions for each pathogen. There were no statistically significant (P > 0.05) differences in reduction between surface- and internally inoculated pathogens at the end of NIR treatment (50 s). However, when treated with conventional convective heating, significant (P 0.05) different from those of nontreated samples. These results suggest that NIR heating can be applied to control internalized pathogens as well as surface-adhering pathogens in RTE sliced meats without affecting product quality.

  10. Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

    Science.gov (United States)

    Gumus, Tuncay; Şukru Demirci, A.; Murat Velioglu, H.; Velioglu, Serap D.; Yilmaz, Ismail; Sagdic, Osman

    2008-09-01

    In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples ( pmeatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses.

  11. The impact of a cold chain break on the survival of Salmonella enterica and Listeria monocytogenes on minimally processed 'Conference' pears during their shelf life.

    Science.gov (United States)

    Colás-Medà, Pilar; Viñas, Inmaculada; Alegre, Isabel; Abadias, Maribel

    2017-07-01

    In recent years, improved detection methods and increased fresh-cut processing of produce have led to an increased number of outbreaks associated with fresh fruits and vegetables. During fruit and vegetable processing, natural protective barriers are removed and tissues are cut, causing nutrient rich exudates and providing attachment sites for microbes. Consequently, fresh-cut produce is more susceptible to microbial proliferation than whole produce. The aim of this study was to examine the impact of storage temperature on the growth and survival of Listeria monocytogenes and Salmonella enterica on a fresh-cut 'Conference' pear over an 8 day storage period. Pears were cut, dipped in antioxidant solution, artificially inoculated with L. monocytogenes and S. enterica, packed under modified atmospheric conditions simulating commercial applications and stored in properly refrigerated conditions (constant storage at 4 °C for 8 days) or in temperature abuse conditions (3 days at 4 °C plus 5 days at 8 °C). After 8 days of storage, both conditions resulted in a significant decrease of S. enterica populations on pear wedges. In contrast, when samples were stored at 4 °C for 8 days, L. monocytogenes populations increased 1.6 logarithmic units, whereas under the temperature abuse conditions, L. monocytogenes populations increased 2.2 logarithmic units. Listeria monocytogenes was able to grow on fresh-cut pears processed under the conditions described here, despite low pH, refrigeration and use of modified atmosphere. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Growth and inactivation of Salmonella enterica and Listeria monocytogenes in broth and validation in ground pork meat during simulated home storage abusive temperature and home pan-frying

    Directory of Open Access Journals (Sweden)

    Xiang eWang

    2015-10-01

    Full Text Available Ground pork meat with natural microbiota and inoculated with low initial densities (1-10 or 10-100 CFU/g of Salmonella enterica or Listeria monocytogenes was stored under abusive temperature at 10°C and thermally treated by a simulated home pan-frying procedure. The growth and inactivation characteristics were also evaluated in broth. In ground pork meat, the population of S. enterica increased by less than one log after 12-days of storage at 10°C, whereas L. monocytogenes increased by 2.3 to 2.8 log units. No unusual intrinsic heat resistance of the pathogens was noted when tested in broth at 60°C although shoulders were observed on the inactivation curves of L. monocytogenes. After growth of S. enterica and L. monocytogenes at 10°C for 5 days to levels of 1.95 log CFU/g and 3.10 log CFU/g, respectively, in ground pork meat, their inactivation in the burger subjected to a simulated home pan-frying was studied. After thermal treatment S. enterica was undetectable but L. monocytogenes was recovered in three out of six of the 25 g burger samples. Overall, the present study shows that data on growth and inactivation of broths are indicative but may underestimate as well as overestimate behavior of pathogens and thus need confirmation in food matrix conditions to assess food safety in reasonably foreseen abusive conditions of storage and usual home pan-frying of of meat burgers in Belgium.

  13. Analysing and modelling the growth behaviour of Listeria monocytogenes on RTE cooked meat products after a high pressure treatment at 400 MPa.

    Science.gov (United States)

    Hereu, A; Dalgaard, P; Garriga, M; Aymerich, T; Bover-Cid, S

    2014-09-01

    Various predictive models are available for high pressure inactivation of Listeria monocytogenes in food, but currently available models do not consider the growth kinetics of surviving cells during the subsequent storage of products. Therefore, we characterised the growth of L. monocytogenes in sliced cooked meat products after a pressurization treatment. Two inoculum levels (10(7) or 10(4) CFU/g) and two physiological states before pressurization (freeze-stressed or cold-adapted) were evaluated. Samples of cooked ham and mortadella were inoculated, high pressure processed (400 MPa, 5 min) and subsequently stored at 4, 8 and 12 °C. The Logistic model with delay was used to estimate lag phase (λ) and maximum specific growth rate (μmax) values from the obtained growth curves. The effect of storage temperature on μmax and λ was modelled using the Ratkowsky square root model and the relative lag time (RLT) concept. Compared with cold-adapted cells the freeze-stressed cells were more pressure-resistant and showed a much longer lag phase during growth after the pressure treatment. Interestingly, for high-pressure inactivation and subsequent growth, the time to achieve a concentration of L. monocytogenes 100-fold (2-log) higher than the cell concentration prior to the pressure treatment was similar for the two studied physiological states of the inoculum. Two secondary models were necessary to describe the different growth behaviour of L. monocytogenes on ready-to-eat cooked ham (lean product) and mortadella (fatty product). This supported the need of a product-oriented approach to assess growth after high pressure processing. The performance of the developed predictive models for the growth of L. monocytogenes in high-pressure processed cooked ham and mortadella was evaluated by comparison with available data from the literature and by using the Acceptable Simulation Zone approach. Overall, 91% of the relative errors fell into the Acceptable Simulation Zone

  14. Beginning ASP.NET 4.5 in C#

    CERN Document Server

    MacDonald, Matthew

    2012-01-01

    This book is the most comprehensive and up to date introduction to ASP.NET ever written. Focussing solely on C#, with no code samples duplicated in other languages, award winning author Matthew MacDonald introduces you to the very latest thinking and best practices for the ASP.NET 4.5 technology.Assuming no prior coding experience, you'll be taught everything you need to know from the ground up.  Starting from first principals, you'll learn the skills you need to be an effective ASP.NET developer who is ready to progress to more sophisticated projects and professional work. You'll be taught ho

  15. Photoreaction of 4,5',8-trimethylpsoralen with adenosine

    International Nuclear Information System (INIS)

    Sangchul Shim; Seungju Choi

    1990-01-01

    The near-UV induced photoreaction of 4,5',8-trimethylpsoralen (TMP) with adenosine was investigated in a dry film state. Four major photoadducts were isolated and purified by reverse-phase liquid chromatography. The structures of the photoproducts were elucidated on the basis of spectroscopic methods, including UV, FT-IR, mass spectrometry (FAB and EI methods) and 1 H-NMR analysis. These photoproducts were characterized to be TMP-adenosine 1:1 adducts, which resulted from the covalent bond formation between the carbon C(4) of TMP and ribose 1' or 5' carbon of adenosine. Of the photoadducts, one photoadduct (V) was the major product, reflecting some selectivity in the photoreaction of TMP with adenosine in the solid state. (author)

  16. 3,4,5-trihydroxybenzoic acid as chelating agent

    International Nuclear Information System (INIS)

    Agrawal, M.D.; Bhandari, C.S.; Dixit, M.K.; Sogani, N.C.

    1976-01-01

    Stability constants of praseodymium chelates of 3,4,5-trihydroxy sodium benzoate are determined by using Bjerrum-Calvin pH titration techniques at constant ionic strength 0.1M-sodium perchlorate and at 28+-0.1 0 C. Values calculated by different methods are in good agreement. The study reveals that during complexation only one proton of the ligand molecule is replaced by the metal and oxygen of adjacent phenolic group acts as a coordinating atom. IR and NMR spectral studies of the ligand reveal that one of the OH groups (in meta position to carboxylic group) remains free while two other phenolic groups are involved in intramolecular hydrogen bonding. One water molecule is found attached in crystalline gallic acid. (author)

  17. N,N′-Dicyclohexylnaphthalene-1,8;4:5-dicarboximide

    Directory of Open Access Journals (Sweden)

    Manju Rajeswaran

    2008-09-01

    Full Text Available The title compound, C26H26N2O4, synthesized by the reaction of naphthalene-1,4,5,8-tetracarboxylic acid anhydride and cyclohexylamine, exhibits good n-type semiconducting properties. Accordingly, thin-film transistor devices comprising this compound show n-type behavior with high field-effect electron moblity ca 6 cm2/Vs [Shukla, Nelson, Freeman, Rajeswaran, Ahearn, Meyer & Carey(2008. Chem. Mater. Submitted]. The asymmetric unit comprises one-quarter of the centrosymmetric molecule in which all but two methylene C atoms of the cyclohexane ring lie on a mirror plane; the point-group symmetry is 2/m. The naphthalenediimide unit is strictly planar, and the cyclohexane rings adopt chair conformations with the diimide unit in an equatorial position on each ring.

  18. 4-Chloroanilinium 2-carboxy-4,5-dichlorobenzoate

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2009-09-01

    Full Text Available The structure of the 1:1 proton-transfer compound of 4-chloroaniline with 4,5-dichlorophthalic acid (DCPA, viz. C6H7ClN+·C8H3Cl2O4−, has been determined at 130 K. The non-planar hydrogen phthalate anions and the 4-chloroanilinium cations form two-dimensional O—H...O and N—H...O hydrogen-bonded substructures which have no peripheral extension. Between the sheets there are weak π–π associations between alternating cation–anion aromatic ring systems [shortest centroid–centroid separation = 3.735 (4 Å].

  19. Prevalence and location of Listeria monocytogenes in farmed rainbow trout.

    Science.gov (United States)

    Miettinen, Hanna; Wirtanen, Gun

    2005-10-15

    A total of 510 rainbow trout originating from fish farms in lakes and sea areas around Finland were studied for the presence of Listeria monocytogenes. Samples were studied as pools from five fish. Gill, viscera, and skin from the pooled samples were analysed separately. The individual samples were analysed later if the pooled sample was found to be Listeria positive. The prevalence of Listeria spp. and L. monocytogenes in pooled unprocessed fresh rainbow trout was on average 35.0% and 14.6%, respectively. On the other hand, the prevalence of Listeria spp. and L. monocytogenes in individual thawed fish was found to be 14.3% and 8.8%, respectively. These numbers tend to overestimate and underestimate the real situation because not all fish in pooled samples were necessarily contaminated and in some of the Listeria positive pooled samples all individual samples turned out to be Listeria free. The prevalence of L. monocytogenes varied greatly between different fish farms from zero to 100% in pooled samples and from zero to 75% according to individually studied fish samples. Some indications of the influence of weather conditions and seasonal variations that strongly affected the Listeria contamination of fish were also noticed. The location of Listeria spp. and L. monocytogenes in different parts of the fish differed with statistical significance in rainbow trout. Up to 95.6% of the L. monocytogenes and 84.5% of Listeria spp. positive samples were gill samples. Only 4.4% (2/45) of the L. monocytogenes positive samples were obtained from skin or viscera. Closer study at one fish farm revealed that there was only one L. monocytogenes ribotype present in the contaminated fish, although water and surfaces were heavily contaminated with six other L. monocytogenes ribotypes.

  20. Incorporation of Listeria monocytogenes strains in raw milk biofilms.

    Science.gov (United States)

    Weiler, Christiane; Ifland, Andrea; Naumann, Annette; Kleta, Sylvia; Noll, Matthias

    2013-02-01

    Biofilms develop successively on devices of milk production without sufficient cleaning and originate from the microbial community of raw milk. The established biofilm matrices enable incorporation of pathogens like Listeria monocytogenes, which can cause a continuous contamination of food processing plants. L. monocytogenes is frequently found in raw milk and non-pasteurized raw milk products and as part of a biofilm community in milk meters and bulk milk tanks. The aim of this study was to analyze whether different L. monocytogenes strains are interacting with the microbial community of raw milk in terms of biofilm formation in the same manner, and to identify at which stage of biofilm formation a selected L. monocytogenes strain settles best. Bacterial community structure and composition of biofilms were analyzed by a cloning and sequencing approach and terminal restriction fragment length polymorphism analysis (T-RFLP) based on the bacterial 16S rRNA gene. The chemical composition of biofilms was analyzed by Fourier transform infrared spectroscopy (FTIR), while settled L. monocytogenes cells were quantified by fluorescence in situ hybridization (FISH). Addition of individual L. monocytogenes strains to raw milk caused significant shifts in the biofilm biomass, in the chemical as well as in the bacterial community composition. Biofilm formation and attachment of L. monocytogenes cells were not serotype but strain specific. However, the added L. monocytogenes strains were not abundant since mainly members of the genera Citrobacter and Lactococcus dominated the bacterial biofilm community. Overall, added L. monocytogenes strains led to a highly competitive interaction with the raw milk community and triggered alterations in biofilm formation. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Listeria monocytogenes as a vector for anti-cancer therapies.

    LENUS (Irish Health Repository)

    Tangney, Mark

    2012-01-31

    The intracellular pathogen Listeria monocytogenes represents a promising therapeutic vector for the delivery of DNA, RNA or protein to cancer cells or to prime immune responses against tumour-specific antigens. A number of biological properties make L. monocytogenes a promising platform for development as a vector for either gene therapy or as an anti-cancer vaccine vector. L. monocytogenes is particularly efficient in mediating internalization into host cells. Once inside cells, the bacterium produces specific virulence factors which lyse the vaculolar membrane and allow escape into the cytoplasm. Once in the cytosol, L. monocytogenes is capable of actin-based motility and cell-to-cell spread without an extracellular phase. The cytoplasmic location of L. monocytogenes is significant as this potentiates entry of antigens into the MHC Class I antigen processing pathway leading to priming of specific CD8(+) T cell responses. The cytoplasmic location is also beneficial for the delivery of DNA (bactofection) by L. monocytogenes whilst cell-to-cell spread may facilitate access of the vector to cells throughout the tumour. Several preclinical studies have demonstrated the ability of L. monocytogenes for intracellular gene or protein delivery in vitro and in vivo, and this vector has also displayed safety and efficacy in clinical trial. Here, we review the features of the L. monocytogenes host-pathogen interaction that make this bacterium such an attractive candidate with which to induce appropriate therapeutic responses. We focus primarily upon work that has led to attenuation of the pathogen, demonstrated DNA, RNA or protein delivery to tumour cells as well as research that shows the efficacy of L. monocytogenes as a vector for tumour-specific vaccine delivery.

  2. Comparison of Inoculation with the InoqulA and WASP Automated Systems with Manual Inoculation

    Science.gov (United States)

    Croxatto, Antony; Dijkstra, Klaas; Prod'hom, Guy

    2015-01-01

    The quality of sample inoculation is critical for achieving an optimal yield of discrete colonies in both monomicrobial and polymicrobial samples to perform identification and antibiotic susceptibility testing. Consequently, we compared the performance between the InoqulA (BD Kiestra), the WASP (Copan), and manual inoculation methods. Defined mono- and polymicrobial samples of 4 bacterial species and cloudy urine specimens were inoculated on chromogenic agar by the InoqulA, the WASP, and manual methods. Images taken with ImagA (BD Kiestra) were analyzed with the VisionLab version 3.43 image analysis software to assess the quality of growth and to prevent subjective interpretation of the data. A 3- to 10-fold higher yield of discrete colonies was observed following automated inoculation with both the InoqulA and WASP systems than that with manual inoculation. The difference in performance between automated and manual inoculation was mainly observed at concentrations of >106 bacteria/ml. Inoculation with the InoqulA system allowed us to obtain significantly more discrete colonies than the WASP system at concentrations of >107 bacteria/ml. However, the level of difference observed was bacterial species dependent. Discrete colonies of bacteria present in 100- to 1,000-fold lower concentrations than the most concentrated populations in defined polymicrobial samples were not reproducibly recovered, even with the automated systems. The analysis of cloudy urine specimens showed that InoqulA inoculation provided a statistically significantly higher number of discrete colonies than that with WASP and manual inoculation. Consequently, the automated InoqulA inoculation greatly decreased the requirement for bacterial subculture and thus resulted in a significant reduction in the time to results, laboratory workload, and laboratory costs. PMID:25972424

  3. Prevalence of Listeria monocytogenes in raw milk in North Lebanon

    International Nuclear Information System (INIS)

    Al Kassaa, I; El Omari, Kh.; Esmail, B.; Hamze, M; Saati, M.

    2016-01-01

    Listeriosis, although a zoonosis, is an invasive disease that can affect newborns, pregnant women and immunocompromised adults. Clinical manifestations can be expressedby febrile gastroenteritis, invasive forms including severe sepsis, meningitis, rhombencephalitis, prenatal infections and abortions. Species of Listeria bacteria are ubiquitous and adaptableto the environment in animal and plant foods. This study aimed to determine the prevalence of Listeria monocytogenes in 100 samples of fresh cow milk collected from different areas of North Lebanon. Listeria monocytogenes was detected by using the Grand VIDAS technique (Biomérieux France). The results obtained revealed the absence of Listeria monocytogenes inall analyzed samples. (Author)

  4. LACTIC FLORA-LISTERIA MONOCYTOGENES INTERACTION

    Directory of Open Access Journals (Sweden)

    S. Colombo

    2012-08-01

    Full Text Available The EC Regulation 2073/2005 (1 requires that food processors evaluate the capability of ready-to-use (RTE products to support the development of Listeria monocytogenes when their pH and aW values are favourable to the growth of this microorganism. It is renown that the lactic flora plays an important role in many different foods, both from a technological and a food safety standpoint. This study was aimed to observe the behaviour and the potential anti-Listeria effect of some natural lactic flora present in Italian liver patè crostini (chicken heart and liver, anchovies, onions, capers, starch, no added preservatives through the Combase Predictor – Max Growth Rate predictive software. The natural lactic flora of the crostini demonstrated a variable capability to inhibit the growth of Listeria monocytogenes which depends upon : the concentration of the lactic flora at the beginning of the shelf life period and the subsequent lag phase, the possible release of anti-Listeria substances, and the maximum growth rate.

  5. Silver as antibacterial towards Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Simone eBelluco

    2016-03-01

    Full Text Available Listeria monocytogenes is a serious foodborne pathogen that can contaminate food during processing and can grow during food shelf-life. New types of safe and effective food contact materials embedding antimicrobial agents, like silver, can play an important role in the food industry. The present work aimed at evaluating the in vitro growth kinetics of different strains of L. monocytogenes in the presence of silver, both in its ionic and nano form. The antimicrobial effect was determined by assaying the number of culturable bacterial cells, which formed colonies after incubation in the presence of silver nanoparticles (AgNPs or silver nitrate (AgNO3. Ionic release experiments were performed in parallel. A different reduction of bacterial viability between silver ionic and nano forms was observed, with a time delayed effect exerted by AgNPs. An association between antimicrobial activity and ions concentration was shown by both silver chemical forms, suggesting the major role of ions in the antimicrobial mode of action.

  6. REALIS: Postgenomic Analysis of Listeria Monocytogenes

    Directory of Open Access Journals (Sweden)

    The REALIS Consortium

    2006-04-01

    Full Text Available Listeria monocytogenes is a remarkably successful food-borne pathogen. It is capable a of surviving and proliferating under conditions that exist within the food chain, such as at low temperatures, high salt and low pH and b of colonizing animal host tissues after ingestion of contaminated food, causing opportunistic infections mainly, but not exclusively, in immunocompromised hosts. The ultimate goals of REALIS are two fold: Firstly, it aims to completely decipher all genes required for survival in and adaptation of Listeria monocytogenes to two very different environments, ie., the infected host and the external environment. Secondly, using genomics and postgenomic tools, REALIS seeks to precisely address fundamental questions regarding evolutionary relationships between pathogenic and non-pathogenic Listeria and to define qualities of particularly successful clonal pathovariants in causing disease. This project will provide both industry and health care managers with rational approaches to curbing food-borne contamination, minimising risks of infection and providing novel pharmacological approaches for halting the fulminant course of infection.

  7. Prevalence and challenge tests of Listeria monocytogenes in Belgian produced and retailed mayonnaise-based deli-salads, cooked meat products and smoked fish between 2005 and 2007.

    Science.gov (United States)

    Uyttendaele, M; Busschaert, P; Valero, A; Geeraerd, A H; Vermeulen, A; Jacxsens, L; Goh, K K; De Loy, A; Van Impe, J F; Devlieghere, F

    2009-07-31

    Processed ready-to-eat (RTE) foods with a prolonged shelf-life under refrigeration are at risk products for listeriosis. This manuscript provides an overview of prevalence data (n=1974) and challenge tests (n=299) related to Listeria monocytogenes for three categories of RTE food i) mayonnaise-based deli-salads (1187 presence/absence tests and 182 challenge tests), ii) cooked meat products (639 presence/absence tests and 92 challenge tests), and iii) smoked fish (90 presence/absence tests and 25 challenge tests), based on data records obtained from various food business operators in Belgium in the frame of the validation and verification of their HACCP plans over the period 2005-2007. Overall, the prevalence of L. monocytogenes in these RTE foods in the present study was lower compared to former studies in Belgium. For mayonnaise-based deli-salads, in 80 out of 1187 samples (6.7%) the pathogen was detected in 25 g. L. monocytogenes positive samples were often associated with smoked fish deli-salads. Cooked meat products showed a 1.1% (n=639) prevalence of the pathogen. For both food categories, numbers per gram never exceeded 100 CFU. L. monocytogenes was detected in 27.8% (25/90) smoked fish samples, while 4/25 positive samples failed to comply to the 100 CFU/g limit set out in EU Regulation 2073/2005. Challenge testing showed growth potential in 18/182 (9.9%) deli-salads and 61/92 (66%) cooked meat products. Nevertheless, both for deli-salads and cooked meat products, appropriate product formulation and storage conditions based upon hurdle technology could guarantee no growth of L. monocytogenes throughout the shelf-life as specified by the food business operator. Challenge testing of smoked fish showed growth of L. monocytogenes in 12/25 samples stored for 3-4 weeks at 4 degrees C. Of 45 (non-inoculated) smoked fish samples (13 of which were initially positive in 25 g) which were subjected to shelf-life testing, numbers exceeded 100 CFU/g in only one sample

  8. Evaluation of bacteriocin-producing Lactobacillus sakei 1 against Listeria monocytogenes 1/2a growth and haemolytic activity Avaliação de Lactobacillus sakei 1 produtor de bacteriocina frente a Listeria monocytogenes 1/2a e sua atividade hemolítica

    Directory of Open Access Journals (Sweden)

    Rafael C.R. Martinez

    2005-03-01

    Full Text Available Bacteriocin-producing Lactobacillus sakei 1 was cultivated in Brain-Heart Infusion broth (24 h at 25ºC. The culture supernatant was neutralized, filter sterilized and used to test the activity of bacteriocin against Listeria monocytogenes 1/2a, at 8ºC and 15ºC. Non-bacteriocinogenic Lactobacillus sakei ATCC 15521 was used as a negative control. L. monocytogenes 1/2a was inoculated in culture supernatant medium from L. sakei 1 and L. sakei ATCC 15521 and the listerial populations were determined after 0, 5 and 10 days. The bacteriocin production was quantified as arbitrary units per mL (AU/mL using agar antagonism test. Additionally, to investigate if L. monocytogenes virulence pattern could be changed after bactericion exposure, the ability of L. monocytogenes to cause haemolysis in sheep red blood cells was determined, before and after exposure to bacteriocin at 8ºC. In the presence of the antimicrobial peptide, at 8ºC, L. monocytogenes population decreased, but growth of resistant cells was observed. At 15ºC, there was no difference between test and control. Furthermore, the haemolytic activity of L. monocytogenes 1/2a was not altered by exposure to L. sakei 1 bacteriocin, which suggests no change in its virulence pattern.Lactobacillus sakei 1 produtor de bacteriocina foi cultivado em caldo Infusão Cérebro-Coração por 24h a 25ºC. O sobrenadante da cultura foi neutralizado, esterilizado por filtração e usado para testar a atividade da bacteriocina frente a Listeria monocytogenes 1/2a, a 8ºC e 15ºC. Lactobacillus sakei ATCC 15521 não bacteriocinogênico, foi utilizado como controle negativo. L. monocytogenes 1/2a foi inoculada no sobrenadante da cultura de L.sakei 1 e L. sakei ATCC 15521 e as populações listeriais foram determinadas após 0, 5 e 10 dias. A produção de bacteriocina foi quantificada como unidades arbitrárias por mL (UA/mL, utilizando-se o teste de antagonismo em ágar. Adicionalmente, para investigar se o padr

  9. Enhanced Control of Listeria monocytogenes by Enterococcus faecium KE82, a Multiple Enterocin-Producing Strain, in Different Milk Environments.

    Science.gov (United States)

    Vandera, Elpiniki; Lianou, Alexandra; Kakouri, Athanasia; Feng, Jinbo; Koukkou, Anna-Irini; Samelis, John

    2017-01-01

    Enterococcus faecium KE82, isolated from traditional Greek Graviera cheese, was identified in pure broth cultures in vitro as a multiple enterocin-producing bacterial strain possessing the structural entA, entB, and entP enterocin genes. E. faecium KE82 was further assessed for in situ antilisterial activity in raw milk (RM) and commercially thermized milk (TM; 63°C for 30 s) in the presence of the indigenous microbiota and in sterile raw milk (SRM; 121°C for 5 min) with or without the addition of two commercial starter culture (CSC) strains Streptococcus thermophilus and Lactococcus lactis . Growth of Listeria monocytogenes was completely inhibited in RM incubated at 37°C for 6 h, whereas the pathogen was significantly inactivated in RM+KE82 samples during further incubation at 18°C for 66 h. In contrast, L. monocytogenes levels increased by approximately 2 log CFU/ml in TM, but in TM+KE82 samples, pathogen growth was retarded during the first 6 h at 37°C followed by growth cessation and partial inactivation at 18°C. After 48 to 72 h, growth of L. monocytogenes in SRM+CSC samples decreased by 4 to 5 log CFU/ml compared with the SRM control, whereas additional 10-fold decreases in the pathogen were observed in SRM+CSC+KE82 samples. Reverse transcription PCR analysis of SRM+KE82 and SRM+CSC+KE82 samples confirmed that the entA and entB genes were transcribed, but entP gene transcription was not detected. All RM and SRM samples inoculated with E. faecium KE82 displayed strong in situ inhibitory activity against L. monocytogenes in well diffusion bioassays, whereas activity was weaker to undetectable in comparable or additional TM+KE82 samples; no milk sample without E. faecium KE82 had activity against L. monocytogenes . The findings of this study indicate that E. faecium KE82 is an antilisterial agent that could be used in traditional dairy foods because it concomitantly produces enterocins A and B in situ in milk.

  10. Experimental thermochemical study of 4,5-dichloro-2-nitroaniline

    International Nuclear Information System (INIS)

    Ribeiro da Silva, Manuel A.V.; Ribeiro da Silva, Maria D.M.C.; Lobo Ferreira, Ana I.M.C.; Santos, Ana Filipa L.O.M.; Galvao, Tiago L.P.

    2009-01-01

    The standard (p 0 =0.1MPa) molar enthalpy of formation of 4,5-dichloro-2-nitroaniline, in the gaseous phase, at T = 298.15 K, was derived from the combination of the values of the standard molar enthalpy of formation, in the crystalline phase, at T = 298.15 K, and the standard molar enthalpy of sublimation, at the same temperature. The standard molar enthalpy of formation, in the crystalline phase, at T = 298.15 K, was derived as -(99.7 ± 1.6) kJ . mol -1 from the standard massic energy of combustion, in oxygen, measured by rotating-bomb combustion calorimetry. The standard molar enthalpy of sublimation was calculated, (109.4 ± 0.9) kJ . mol -1 by the application of the Clausius-Clapeyron equation, to the vapour pressures measured at several temperatures by Knudsen effusion technique. The standard molar enthalpies of formation, in the gaseous phase, of the six dichloro-2-nitroaniline isomers and of the four dichloro-4-nitroaniline isomers were estimated by the Cox Scheme and by the Domalski and Hearing group additivity method and compared with the available experimental values. For the Domalski and Hearing group additivity method four new correction terms were derived.

  11. Synthesis of cyclophosphamide-4,4,5,5-d4

    International Nuclear Information System (INIS)

    Walsh, S.P.; Chang, Y.H.; Ludeman, S.M.

    1995-01-01

    3-Hydroxypropionitrile was subjected to a base-catalyzed exchange reaction in D 2 O which provided 2,2-dideuterio-3-deuteroxypropionitrile (DOCH 2 CD 2 CN) in 70% yield. Reduction of the nitrile with LiAID 4 gave 3-amino-2,2,3,3-tetradeuteriopropan-1-ol (HOCH 2 CD 2 CD 2 NH 2 ) in a crude yield of 71%. Reaction of this intermediate with N,N-bis(2-chloroethyl)phosphoramidic dichloride [Cl 2 P(O)N(CH 2 CH 2 Cl) 2 ] followed by the combination of those chromatography fractions which contained only pure material gave cyclophosphamide-4,4,5,5-d 4 as a white oil in 13% yield. A portion of this oil was converted to the monohydrate by the addition of water (1.1 equivalents) and crystallization from ether/petroleum ether (62% yield). For the hydrate, MS analyses gave an average mole percent enrichment (with average deviation over 5 determinations) of 89.1 ± 0.5% d 4 . (author)

  12. ( Rosa damascena Mill.) by microbial inoculation

    African Journals Online (AJOL)

    This study was carried out to determine the effects of microbial inoculation in breaking seed dormancy and on the germination of Rosa damascena Mill. Seeds of R. damascena Mill. are the most used scented rose species in rose oil production. The most important production centers around the world are Turkey and ...

  13. Coping With Pain: Studies in Stress Inoculation.

    Science.gov (United States)

    Horan, John J.; And Others

    The stress-inoculation paradigm for helping clients deal with pain consists of education about the psychological dimensions of pain, training in a number of coping skills relevant to each dimension, and practice in applying these skills to the noxious stimulus. Presented are two studies, the first of which represents a component analysis of stress…

  14. Legume bioactive compounds: influence of rhizobial inoculation

    Directory of Open Access Journals (Sweden)

    Luis R. Silva

    2017-04-01

    Full Text Available Legumes consumption has been recognized as beneficial for human health, due to their content in proteins, fiber, minerals and vitamins, and their cultivation as beneficial for sustainable agriculture due to their ability to fix atmospheric nitrogen in symbiosis with soil bacteria known as rhizobia. The inoculation with these baceria induces metabolic changes in the plant, from which the more studied to date are the increases in the nitrogen and protein contents, and has been exploited in agriculture to improve the crop yield of several legumes. Nevertheless, legumes also contain several bioactive compounds such as polysaccharides, bioactive peptides, isoflavones and other phenolic compounds, carotenoids, tocopherols and fatty acids, which makes them functional foods included into the nutraceutical products. Therefore, the study of the effect of the rhizobial inoculation in the legume bioactive compounds content is gaining interest in the last decade. Several works reported that the inoculation of different genera and species of rhizobia in several grain legumes, such as soybean, cowpea, chickpea, faba bean or peanut, produced increases in the antioxidant potential and in the content of some bioactive compounds, such as phenolics, flavonoids, organic acids, proteins and fatty acids. Therefore, the rhizobial inoculation is a good tool to enhance the yield and quality of legumes and further studies on this field will allow us to have plant probiotic bacteria that promote the plant growth of legumes improving their functionality.

  15. Growth inhibition of Listeria monocytogenes by a nonbacteriocinogenic Carnobacterium piscicola

    DEFF Research Database (Denmark)

    Nilsson, Lilian; Bech Hansen, T.; Garrido, P.

    2005-01-01

    Aims: This study elucidates the mechanisms by which a nonbacteriocinogenic Carnobacterium piscicola inhibits growth of Listeria monocytogenes. Methods and Results: Listeria monocytogenes was exposed to live cultures of a bacteriocin-negative variant of C. piscicola A9b in co-culture, in a diffusion...... chamber system, and to a cell-free supernatant. Suppression of maximum cell density (0-3.5 log units) of L. monocytogenes was proportional to initial levels of C. pisciola (10(3)-10(7) CFU ml(-1)). Cell-to-cell contact was not required to cause inhibition. The cell-free C. piscicola supernatant caused...... a decrease in L. monocytogenes maximum cell density, which was abolished by glucose addition but not by amino acid, vitamin or mineral addition. The fermentate also gave rise to a longer lag phase and a reduction in growth rate. These effects were independent of glucose and may have been caused by acetate...

  16. Effect of atmospheric pressure plasma on inactivation of pathogens inoculated onto bacon using two different gas compositions.

    Science.gov (United States)

    Kim, Binna; Yun, Hyejeong; Jung, Samooel; Jung, Yeonkook; Jung, Heesoo; Choe, Wonho; Jo, Cheorun

    2011-02-01

    Atmospheric pressure plasma (APP) is an emerging non-thermal pasteurization method for the enhancement of food safety. In this study, the effect of APP on the inactivation of pathogens inoculated onto bacon was observed. Sliced bacon was inoculated with Listeria monocytogenes (KCTC 3596), Escherichia coli (KCTC 1682), and Salmonella Typhimurium (KCTC 1925). The samples were treated with APP at 75, 100, and 125 W of input power for 60 and 90 s. Two gases, helium (10 lpm) or a mixture of helium and oxygen, (10 lpm and 10 sccm, respectively) were used for the plasma generation. Plasma with helium could only reduce the number of inoculated pathogens by about 1-2 Log cycles. On the other hand, the helium/oxygen gas mixture was able to achieve microbial reduction of about 2-3 Log cycles. The number of total aerobic bacteria showed 1.89 and 4.58 decimal reductions after plasma treatment with helium and the helium/oxygen mixture, respectively. Microscopic observation of the bacon after plasma treatment did not find any significant changes, except that the L∗-value of the bacon surface was increased. These results clearly indicate that APP treatment is effective for the inactivation of the three pathogens used in this study, although further investigation is needed for elucidating quality changes after treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Listeria monocytogenes, a down-to-earth pathogen.

    Science.gov (United States)

    Vivant, Anne-Laure; Garmyn, Dominique; Piveteau, Pascal

    2013-01-01

    Listeria monocytogenes is the causative agent of the food-borne life threatening disease listeriosis. This pathogenic bacterium received much attention in the endeavor of deciphering the cellular mechanisms that underlie the onset of infection and its ability to adapt to the food processing environment. Although information is available on the presence of L. monocytogenes in many environmental niches including soil, water, plants, foodstuff and animals, understanding the ecology of L. monocytogenes in outdoor environments has received less attention. Soil is an environmental niche of pivotal importance in the transmission of this bacterium to plants and animals. Soil composition, microbial communities and macrofauna are extrinsic edaphic factors that direct the fate of L. monocytogenes in the soil environment. Moreover, farming practices may further affect its incidence. The genome of L. monocytogenes presents an extensive repertoire of genes encoding transport proteins and regulators, a characteristic of the genome of ubiquitous bacteria. Postgenomic analyses bring new insights in the process of soil adaptation. In the present paper focussing on soil, we review these extrinsic and intrinsic factors that drive environmental adaptation of L. monocytogenes.

  18. Biofilm Formation of Listeria monocytogenes on Various Surfaces

    Directory of Open Access Journals (Sweden)

    M Mahdavi

    2007-10-01

    Full Text Available Introduction & Objective: Listeria monocytogenes is considered as a ubiquitous foodborne pathogen which can lead to serious infections, especially in newborns, elderly, pregnant, and immunocompromised people. The organism has been isolated from many foods and may cause meningitis, septicemia and abortion in pregnant women. Also L. monocytogenes forms biofilms on many food contact surface materials and medical devices. Development of biofilms on many surfaces is a potential source of contamination of foods that may lead to spoilage or transmission of foodborne pathogens. Materials & Methods: Biofilm formation of L. monocytogenes (RITCC 1293 serotype 4a was investigated. Hydrophobicity of L. monocytogenes was measured by MATH method. Then biofilm formation of the organism was assessed at 2, 4, 8, 16 and 20 hours on stainless steel (type 304 no 2B, polyethylene and glass by drop plate method. Results: Results indicated that L. monocytogenes with 85% of hydrophobicity formed biofilm on each of three surfaces. Biofilm formation on stainless steel surfaces was significantly more than other surfaces (p<0.05. Conclusion: The ability of biofilm formation of L. monocytogenes on medical devices and food containers is very important as far as hygiene and disease outbreaks are concerned.

  19. Inhibition of sortase A by chalcone prevents Listeria monocytogenes infection.

    Science.gov (United States)

    Li, Hongen; Chen, Yutao; Zhang, Bing; Niu, Xiaodi; Song, Meng; Luo, Zhaoqing; Lu, Gejin; Liu, Bowen; Zhao, Xiaoran; Wang, Jianfeng; Deng, Xuming

    2016-04-15

    The critical role of sortase A in gram-positive bacterial pathogenicity makes this protein a good potential target for antimicrobial therapy. In this study, we report for the first time the crystal structure of Listeria monocytogenes sortase A and identify the active sites that mediate its transpeptidase activity. We also used a sortase A (SrtA) enzyme activity inhibition assay, simulation, and isothermal titration calorimetry analysis to discover that chalcone, an agent with little anti-L. monocytogenes activity, could significantly inhibit sortase A activity with an IC50 of 28.41 ± 5.34 μM by occupying the active site of SrtA. The addition of chalcone to a co-culture of L. monocytogenes and Caco-2 cells significantly inhibited bacterial entry into the cells and L. monocytogenes-mediated cytotoxicity. Additionally, chalcone treatment decreased the mortality of infected mice, the bacterial burden in target organs, and the pathological damage to L. monocytogenes-infected mice. In conclusion, these findings suggest that chalcone is a promising candidate for the development of treatment against L. monocytogenes infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. A case of bovine raw milk contamination with Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Hunt Karen

    2012-07-01

    Full Text Available Abstract During routine sampling of bulk raw milk on a dairy farm, the pathogenic bacteria Listeria monocytogenes was found to be a contaminant, at numbers L. monocytogenes, indicating a possible case of excretion of the L. monocytogenes directly into the milk. Milk samples were collected from the individual cows and analysed, resulting in the identification of L. monocytogenes excretion (at 280 cfu/ml from one of the 4 mammary quarters of one dairy cow out of 180. When the infected cow was isolated from the herd, no L. monocytogenes was detected from the remaining herd. The pulsed-field gel electrophoresis pattern of the strain from the individual cow was indistinguishable from that originally isolated from the bulk milk. The infected cow did not show any clinical signs of disease, nor did the appearance of the milk have any physical abnormalities. Antibiotic treatment of the infected mammary quarter was found to be ineffective. This study shows that there can be risks associated with direct contamination of raw milk with L. monocytogenes.

  1. Prevalence of Listeria monocytogenes in European cheeses

    DEFF Research Database (Denmark)

    Martinez Rios, Veronica; Dalgaard, Paw

    2017-01-01

    , respectively, pasteurized or un-pasteurized milk. Data from a total of 130,604 samples were analysed. Mean prevalence for presence during 2005-2015 estimated from scientific literature (2.3% with confidence interval (CI): 1.4-3.8%) was more than three times higher than results from EFSA reports (0.7%; CI: 0.......05) for cheeses produced from pasteurized (0.9%; CI: 0.4-1.9%) or un-pasteurized (1.0%; CI: 0.4-2.2%) milk. For cheese samples reported by EFSA 0.2% CI: 0.1-0.4% had concentration of L. monocytogenes above the critical European limits of 100 cfu/g. In addition, this systematic review focused on groups...

  2. Sensitivity of Listeria monocytogenes to irradiation

    International Nuclear Information System (INIS)

    Tarjan, Veronika

    1990-01-01

    Irradiation of Listeria monocytogenes (L.m.) was carried out in culture media and pork meat paste at room temperature with 60 Co radiation source of 6.6 kGy h -1 dose rate. The employed doses were 0, 0.5, 1, 2, 3, 4 and 6 kGy. One strain out of 3 survived as high as 4 kGy irradiation. Radiation with 2 kGy resulted 7 log cycles reduction of cell count. After lower irradiation doses the L.m. count decreased in proportion to increasing doses. It has been concluded that L.m. compared with Gram-negative pathogens, are less sensitive to irradiation. (author) 6 refs.; 4 figs

  3. Evaluation of Pure Aluminium Inoculated with Varying Grain Sizes of an Agro-waste based Inoculant

    Directory of Open Access Journals (Sweden)

    Adeyemi I. Olabisi

    2017-04-01

    Full Text Available Pure Aluminium and its alloy are widely utilized in Engineering and Industrial applications due to certain significant properties such as softness, ductility, corrosion resistance, and high electrical conductivity which it possesses. Addition of an agro-waste based grain refiner to the melt can alter the characteristics positively or negatively. Therefore, the aim of this paper is to investigate the inoculating capability of an agro-waste based inoculant and the effect of adding varying sizes of its grains on some of the properties of pure aluminium after solidification. The beneficial outcome of this investigation would enhance the economic value of the selected agro-waste and also broaden the applications of aluminium in Engineering. The assessed properties include; microstructure, micro hardness, ductility, and tensile strength. The agro-waste used as the grain refiner is pulverised cocoa bean shells (CBS. Three sets of test samples were produced using dry sand moulding process, with each melt having a specified grain size of the inoculant added to it (150, 225 and 300microns respectively. Ladle inoculation method was adopted. The cast samples after solidification were machined to obtain various shapes/sizes for the different analysis. The microstructural examination showed that the mechanical properties are dependent on the matrix as the aluminium grains became more refined with increasing grain size of the inoculant. I.e. Due to increasing grain size of the inoculant, the micro hardness increased (56, 61, 72HB as the aluminium crystal size became finer. Meanwhile, the tensile strength (284, 251, 223N/mm2 and ductility (1.82, 0.91, 0.45%E decreased as grain size of the inoculant increased. The overall results showed that the used agro-waste based inoculant has the capability of refining the crystal size of pure aluminium as its grain size increases. This will make the resulting aluminium alloy applicable in areas where hardness is of

  4. Prevalence of Listeria species in camel sausages from retail markets in Aydin province in Turkey and RAPD analysis of Listeria monocytogenes Isolates

    Directory of Open Access Journals (Sweden)

    Ozbey Gokben

    2006-06-01

    Full Text Available Abstract Samples were taken from 100 camel sausages from the different retail markets in Aydin province in the south-west of Turkey and they were tested for the presence of Listeria spp by biochemical methods. Samples were enriched using Listeria Enrichment Broth and they were inoculated onto Listeria Selective Agar. Listeria monocytogenes was isolated from nine samples (9%, Listeria innocua from 14 samples (14% and Listeria welshimeri from two samples(2%. A 701 bp fragment of listeriolysin O sequence for L. monocytogenes was amplified using specific primers by polymerase chain reaction (PCR for confirmation of the identification. A random primer (OPA-11 was used in a random amplified polymorphic DNA (RAPD assay. This detected five different band profiles amongst the L. monocytogenes isolates, indicating a relatively large amount of genetic heterogeneity amongst the nine isolates. The study has highlighted the need for improved strategies for food safety, in particular appropriate hygienic precautions to avoid contamination of sausage during the manufacturing process and appropriate preservation techniques during storage and transport, to prevent transmission of Listeria spp to consumers at home and abroad.

  5. Effect of gamma radiation on the reduction of Salmonella strains, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli and sensory evaluation of minimally processed spinach (Tetragonia expansa).

    Science.gov (United States)

    Rezende, Ana Carolina B; Igarashi, Maria Crystina; Destro, Maria Teresa; Franco, Bernadette D G M; Landgraf, Mariza

    2014-10-01

    This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

  6. Impact of preheating on the behavior of Listeria monocytogenes in a broth that mimics Camembert cheese composition.

    Science.gov (United States)

    Helloin, E; Bouttefroy, A; Gay, M; Phan Thanh, L

    2003-02-01

    The effect of preheating on the survival of L. monocytogenes in Richard's broth, which mimics the composition of Camembert cheese composition, was examined. Experiments were carried out to reproduce contamination of cheese with environmental heat-stressed cells of L. monocytogenes surviving hot-cleaning procedures. Cells in mid-log phase were heated for 30 min at 56 degrees C before being inoculated into Richard's broth. The pHs and temperatures of Richard's broth were chosen to recreate the conditions of curd dripping (pH 5, 25 degrees C), of the beginning of cheese ripening (pH 5, 12 degrees C), and of the beginning (pH 5, 4 degrees C) and the end (pH 7, 4 degrees C) of cheese storage. Immediately after heat treatment, the viability loss was especially high for strain 306715, which exhibited only 0.6% +/- 0.2% survival, compared with 22% +/- 8.7% for strain EGD. The percentages of the surviving heated cells that were injured were 93% +/- 8% for strain 306715 and 98% +/- 3% for strain EGD. The destruction of the surviving L. monocytogenes cells was accelerated when they encountered the pH and temperature conditions of Camembert cheese during manufacturing, ripening, and cold storage (pH 5 at 25, 12, and 4 degrees C, respectively). The multiplication of the surviving heated cells was retarded under favorable growth conditions similar to those of storage by the distributor and the consumer (pH 7 at 4 and 12 degrees C, respectively).

  7. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Joo [Department of Food Science and Technology, Chung-Ang University, Ansung, Gyunggi-do 456-756 (Korea, Republic of); Ham, Jun-Sang [Animal Products Processing Division, National Livestock Research Institute, RDA, Suwon 441-706 (Korea, Republic of); Lee, Ju-Woon [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kim, Keehyuk [Department of Culinary Nutrition, Woosong University, Daejeon 300-718 (Korea, Republic of); Ha, Sang-Do [Department of Food Science and Technology, Chung-Ang University, Ansung, Gyunggi-do 456-756 (Korea, Republic of); Jo, Cheorun, E-mail: cheorun@cnu.ac.k [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2010-06-15

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens (Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10{sup 2} to 10{sup 3} Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10{sup 1} CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D{sub 10} values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  8. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    International Nuclear Information System (INIS)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-01-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens (Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  9. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    Science.gov (United States)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-06-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens ( Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  10. Listeria monocytogenes - Danger for health safety vegetable production.

    Science.gov (United States)

    Kljujev, Igor; Raicevic, Vera; Jovicic-Petrovic, Jelena; Vujovic, Bojana; Mirkovic, Milica; Rothballer, Michael

    2018-04-22

    The microbiologically contaminated vegetables represent a risk for consumers, especially vegetables without thermal processing. It is known that human pathogen bacteria, such as Listeria monocytogenes, could exist on fresh vegetables. The fresh vegetables could become Listeria-contaminated if they come in touch with contaminated soil, manure, irrigation water. The aim of this work was to investigate the presence of Listeria spp. and L. monocytogenes in different kind of vegetables grown in field and greenhouse condition as well as surface and endophytic colonization plant roots of different vegetables species by L. monocytogenes in laboratory conditions. The detection of Listeria spp. and L. monocytogenes in vegetable samples was done using ISO and PCR methods. The investigation of colonization vegetable roots and detection Listeria-cells inside plant root tissue was done using Fluorescence in situ hybridization (FISH) method in combination with confocal laser scanning microscopy (CLSM). The results showed that 25.58% vegetable samples were positive for Listeria spp. and only one sample (carrot) was positive for L. monocytogenes out of 43 samples in total collected from field and greenhouse. The strain L. monocytogenes EGD-E surface and endophytic colonized carrot root in highest degree while strain L. monocytogenes SV4B was the most represented at leafy vegetable plants, such at lettuce (1.68 × 10 6  cells/mm 3 absolutely dry root) and spinach (1.39 × 10 6  cells/mm 3 absolutely dry root) root surface. The cells of L. monocytogenes SV4B were visible as single cells in interior tissue of plant roots (celery and sweet corn roots) as well as in the interior of the plant root cell at sweet corn root. The cells of L. monocytogenes EGD-E bind to the surface of the plant root and they were less commonly found out on root hair. In the inner layers of the root, those bacterial cells were inhabited intercellular spaces mainly as single cells very close to the

  11. Synthesis and characterization of new 3-(4,5-dihydro-5-arylisoxazol-3-yl-4-hydroxyquinolin-2(1H-ones and 3-(4-styrylisoxazolo[4,5-c]quinolin-4(5H-one derivatives

    Directory of Open Access Journals (Sweden)

    S. Sarveswari

    2016-09-01

    Full Text Available The 4-hydroxy-3-(3-arylacryloylquinolin-2(1H-ones were synthesized from 3-acetyl-4-hydroxyquinolin-2(1H-one by microwave assisted synthesis, which in turn converted into their corresponding 3-(4,5-dihydro-5-arylisoxazol-3-yl-4-hydroxyquinolin-2(1H-ones and 3-(4-styrylisoxazolo[4,5-c]quinolin-4(5H-one derivatives.

  12. Diversity Assessment of Heat Resistance of Listeria monocytogenes Strains in a Continuous-Flow Heating System

    NARCIS (Netherlands)

    Veen, van der S.; Wagendorp, A.; Abee, T.; Wells-Bennik, M.H.J.

    2009-01-01

    Listeria monocytogenes is a foodborne pathogen that has the ability to survive relatively high temperatures compared with other nonsporulating foodborne pathogens. This study was performed to determine whether L. monocytogenes strains with relatively high heat resistances are adequately inactivated

  13. Behaviour of co-inoculated pathogenic and spoilage bacteria on poultry following several decontamination treatments.

    Science.gov (United States)

    Alonso-Hernando, Alicia; Capita, Rosa; Alonso-Calleja, Carlos

    2012-10-01

    The potential of chemical decontaminants to cause harmful effects on human health is among the causes of the rejection of antimicrobial treatments for removing surface contamination from poultry carcasses in the European Union. This study was undertaken to determine whether decontaminants might give a competitive advantage to pathogenic bacteria on poultry and involve a potential risk to consumer. A total of 144 chicken legs were co-inoculated with similar concentrations of pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica serotype Enteritidis or Escherichia coli) and spoilage bacteria (Brochothrix thermosphacta or Pseudomonas fluorescens). Samples were dipped for 15min in solutions (w/v) of trisodium phosphate (12%; TSP), acidified sodium chlorite (1200ppm; ASC), citric acid (2%; CA), peroxyacids (220ppm; PA) or chlorine dioxide (50ppm; CD), or were left untreated (control). Microbiological analyses were carried out on day 0 and every 24h until day 7 of storage (at 10±1°C). The modified Gompertz equation was used as the primary model to fit observed data. TSP, ASC and CA were effective in extending the lag phase (L, ranging from 1.47±1.34days to 4.06±1.16days) and in decreasing the concentration of bacteria during the stationary phase (D, ranging from 2.46±0.51 log(10) cfu/cm(2) to 8.64±0.53 log(10) cfu/cm(2)), relative to the control samples (L values ranging from 0.59±0.38days and 2.52±2.28days, and D values ranging from 6.32±0.89 log(10) cfu/cm(2) to 9.39±0.39 log(10) cfu/cm(2), respectively). Both on untreated and on most decontaminated samples the overgrowth of spoilage bacteria among the species tested was observed throughout storage, suggesting that spoilage would occur prior to any noteworthy increase in the levels of pathogenic microorganisms. However, L. monocytogenes counts similar to, or higher than, those for spoilage bacteria were observed on samples treated with TSP, ASC or CA, suggesting that these

  14. Inoculation stress hypothesis of environmental enrichment.

    Science.gov (United States)

    Crofton, Elizabeth J; Zhang, Yafang; Green, Thomas A

    2015-02-01

    One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Influence of Inoculation, Nitrogen and Phosphorus Levels on Wheat Growth and Soil Microbial Biomass-N Using 15N Techniques

    International Nuclear Information System (INIS)

    Galal, Y.G.; El-Ghandour, I.A.; Abdel Raouf, A.M.; Osman, M.E.

    2003-01-01

    Pot experiment was carried out with wheat that cultivated in virgin sandy soil and inoculated with Rhizobium (Rh), mycorrhizea (VAM) and mixture of both. The objective of this work was to verify the potential of these inoculum on wheat production, nutrient acquisition and microbial biomass N (MBN) contribution as affected by N and P fertilizers levels. MBN was detected through the fumigation-extraction method. Nitrogen and phosphorus fertilizers were applied at three levels, 0; 25 ppm N and 3.3 ppm P and 50 ppm N and 6.6 ppm P in the form of ( 15 NH 4 ) 2 SO 4 , 5% atom excess and super-phosphate, respectively. The effect of inoculation and chemical fertilizers on dry matter (DM), N and P uptake (shoot and grain) and MBN were traced. The obtained data revealed that the highest DM and N uptake by wheat shoot were recorded with the dual inoculation (Rh + VAM) at the highest level of N and P fertilizers. The highest grain yield was detected with single inoculum of AM fungi while N and P uptake were with dual inoculation at the same rate of fertilizers. Inoculation with Rh either alone or in combination with VAM have a positive and stimulative effect on wheat growth and N and P uptake indicating the possibilities of extending the use of symbiotic microorganisms to be applied with cereals. The fluctuation in the soil microbial biomass N did not gave a chance to recognize, exactly, the impact of inoculation and/or fertilization levels

  16. Meningoencefalite por Listeria monocytogenes em ovinos Meningoencephalitis in sheep caused by Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Daniel R. Rissi

    2010-01-01

    Full Text Available São descritos sete casos de doença neurológica em ovinos por Listeria monocytogenes no Rio Grande do Sul e Paraná entre 2000 e 2007. Foram afetados ovinos com idades entre 12-24 meses. Os casos ocorreram no verão e início da primavera e os índices gerais de morbidade e letalidade foram de 3,15% e 100%, respectivamente. Quando essa informação estava disponível, nenhum dos ovinos afetados era alimentado com silagem. Em três propriedades havia contato próximo dos ovinos afetados com outras espécies. A evolução do quadro clínico foi de 12 horas a três dias e os sinais clínicos foram caracterizados por decúbito (7/7, desvio da cabeça (4/7, incoordenação (3/7, depressão (3/7, andar em círculos (2/7, cegueira unilateral, emagrecimento progressivo, febre, midríase, movimentos de pedalagem, nistagmo lateral, opistótono, paralisia flácida dos membros pélvicos ou dos quatro membros, salivação excessiva e tremores (1/7 cada. Histologicamente observou-se encefalite com microabscessos, predominantemente unilateral com variáveis graus de gliose e alterações degenerativas como esferóides axonais e infiltração de células Gitter. As lesões se estendiam desde a medula oblonga até o mesencéfalo. Antígenos de Listeria monocytogenes foram detectados por imuno-histoquímica em seções de tronco encefálico de todos os ovinos afetados. O diagnóstico foi realizado com base nos achados epidemiológicos e clinico-patológicos, e confirmado pela imuno-histoquímica (IHQ utilizando anticorpo policlonal anti-L. monocytogenes.Seven cases of neurological disease in sheep caused by Listeria monocytogenes in Rio Grande do Sul and Paraná state, southern Brazil are described. The cases occurred between 2000 and 2007 and 12-24-month-old sheep were affected. Overall morbidity and lethality rates were 3.15% and 100%, respectively. Cases occurred in the summer and early spring. When this information was available, affected sheep had not been

  17. Effect of various conditions on inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in fresh-cut lettuce using ultraviolet radiation.

    Science.gov (United States)

    Kim, Yoon-Hee; Jeong, Seul-Gi; Back, Kyeong-Hwan; Park, Ki-Hwan; Chung, Myung-Sub; Kang, Dong-Hyun

    2013-09-16

    The effect of various conditions on inactivation of foodborne pathogens and quality of fresh-cut lettuce during ultraviolet (254 nm, UVC) radiation was investigated. Lettuce was inoculated with a cocktail of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated at different temperatures (4 and 25 °C), distances between sample and lamp (10 and 50 cm), type of exposure (illuminated from one or two sides), UV intensities (1.36 to 6.80 mW/cm²), and exposure times (0.5 to 10 min), sequentially. UV treatment at 25 °C for 1 min achieved 1.45-, 1.35-, and 2.12-log reductions in surface-inoculated E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, whereas the reduction of these pathogens at 4 °C was 0.31, 0.57, and 1.16 log, respectively. UV radiation was most effective when distance from UV lamp to the sample was minimal (10 cm) and radiation area was maximal (two-sided exposure). All UV intensities significantly (P0.05) different from those of nontreated samples up to 5 min exposure. However, these qualities significantly (Pradiation under optimized conditions could reduce foodborne pathogens without adversely affecting color quality properties of fresh-cut lettuce. © 2013 Elsevier B.V. All rights reserved.

  18. Key factors to inoculate Botrytis cinerea in tomato plants

    OpenAIRE

    Borges,Álefe Vitorino; Saraiva,Rodrigo Moreira; Maffia,Luiz Antonio

    2014-01-01

    Studies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness...

  19. Accessing inoculation methods of maize and wheat with Azospirillum brasilense.

    Science.gov (United States)

    Fukami, Josiane; Nogueira, Marco Antonio; Araujo, Ricardo Silva; Hungria, Mariangela

    2016-03-01

    The utilization of inoculants containing Azospirillum is becoming more popular due to increasing reports of expressive gains in grain yields. However, incompatibility with pesticides used in seed treatments represents a main limitation for a successful inoculation. Therefore, in this study we searched for alternatives methods for seed inoculation of maize and wheat, aiming to avoid the direct contact of bacteria with pesticides. Different doses of inoculants containing Azospirillum brasilense were employed to perform inoculation in-furrow, via soil spray at sowing and via leaf spray after seedlings had emerged, in comparison to seed inoculation. Experiments were conducted first under greenhouse controlled conditions and then confirmed in the field at different locations in Brazil. In the greenhouse, most parameters measured responded positively to the largest inoculant dose used in foliar sprays, but benefits could also be observed from both in-furrow and soil spray inoculation. However, our results present evidence that field inoculation with plant-growth promoting bacteria must consider inoculant doses, and point to the need of fine adjustments to avoid crossing the threshold of growth stimulation and inhibition. All inoculation techniques increased the abundance of diazotrophic bacteria in plant tissues, and foliar spray improved colonization of leaves, while soil inoculations favored root and rhizosphere colonization. In field experiments, inoculation with A. brasilense allowed for a 25 % reduction in the need for N fertilizers. Our results have identified alternative methods of inoculation that were as effective as the standard seed inoculation that may represent an important strategy to avoid the incompatibility between inoculant bacteria and pesticides employed for seed treatment.

  20. Effect of Grapefruit Seed Extract on Thermal Inactivation of Listeria monocytogenes during Sous-Vide Processing of Two Marinated Mexican Meat Entrées.

    Science.gov (United States)

    Valenzuela-Melendres, Martin; Peña-Ramos, E Aida; Juneja, Vijay K; Camou, Juan Pedro; Cumplido-Barbeitia, German

    2016-07-01

    D- and z-values for Listeria monocytogenes were obtained for two Mexican meat entrées: pork meat marinated in tomatillo (green tomato) sauce (PTS) and beef marinated in a red chili sauce (BRCS), with addition of 0, 200, and 800 ppm of grapefruit seed extract (GSE). Meat samples inoculated with L. monocytogenes were packaged in sterile bags, immersed in a water bath, and held at 55, 57.5, 60, and 62.5°C for different periods of time. Depending upon the temperature, D-values at 0 ppm of GSE ranged from 26.19 to 2.03 min in BRCS and 26.41 to 0.8 min in PTS. Adding 800 ppm of GSE to BRCS thermally treated at 55 and 62.5°C significantly decreased inactivation time by 35%. A reduction in time of 25.9, 10.6, and 40.1% at 55, 57.5, and 60°C, respectively, was observed in PTS with 800 ppm of GSE. The z-values of L. monocytogenes were not significantly affected by GSE addition; average z-values were 7.25 and 5.09°C for BRCS and PTS, respectively. Estimated thermal lethality for a 7-D log reduction of L. monocytogenes under commercial-size sous-vide conditions at a reference temperature of 55°C was reached at 78 and 71 min for BRCS without and with 800 ppm of GSE, respectively. For PTS, 7-D reduction was attained at 69 and 61 min without and with addition of 800 ppm of GSE, respectively. Supplementing both Mexican meat entrées (BRCS and PTS) with 800 ppm of GSE rendered L. monocytogenes cells more sensitive to the lethal effect of heat. The results of this study will assist the retail food industry in designing acceptance limits on critical control points pertaining to cooking regimes to effectively eliminate L. monocytogenes in BRCS and PTS sous-vide processed Mexican meat entrées.

  1. PASTEURISASI HIGH TEMPERATURE SHORT TIME (HTST) SUSU TERHADAP Listeria monocytogenes PADA PENYIMPANAN REFRIGERATOR

    OpenAIRE

    SABIL, SYAHRIANA

    2015-01-01

    2015 SYAHRIANA SABIL (I 111 11 273). Pasteurisasi High Temperature Short Time (HTST) Susu terhadap Listeria monocytogenes pada Penyimpanan Refrigerator. Dibimbing oleh RATMAWATI MALAKA dan FARIDA NUR YULIATI. Pasteurisasi High Temperature Short Time (HTST) merupakan proses pemanasan susu di bawah titik didih yang diharapkan dapat membunuh Listeria monocytogenes (L. monocytogenes) karena bersifat patogen dan mengakibatkan listeriosis yang merupakan penyakit zoonosis. Tu...

  2. Industrial disinfectants do not select for resistance in Listeria monocytogenes following long term exposure

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Gram, Lone

    2012-01-01

    or tolerance would evolve in L. monocytogenes under continued selection in three industrial disinfectants. L. monocytogenes EGD was exposed to Desinfect CL (hypochlorite) and Incimaxx DES (peracedic acid and hydrogen peroxide) for several hundred generations. This caused no increase in the minimal inhibitory......, and that the disinfectants are still efficient for controlling microorganisms such as L. monocytogenes....

  3. Comparison of bedside inoculation of culture media with ...

    African Journals Online (AJOL)

    Background: The yield of bacterial cultures from cerebrospinal fluid (CSF) at Kenyatta National Hospital (KNH) is very low. Bedside inoculation of culture media with CSF may improve yields. Objective: To compare the culture yield of CSF inoculated onto culture medium at the bedside to that of CSF inoculated onto culture ...

  4. Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ready-to-bake cookie dough by gamma and electron beam irradiation.

    Science.gov (United States)

    Jeong, Seul-Gi; Kang, Dong-Hyun

    2017-06-01

    This study was conducted to investigate the efficacy of gamma and electron beam irradiation to inactivate foodborne pathogens in ready-to-bake cookie dough and to determine the effect on quality by measuring color and texture changes. Cookie dough inoculated with Escherichia coli O157:H7, Salmonella Typhimurium, or Listeria monocytogenes was subjected to gamma and electron beam irradiation, with doses ranging from 0 to 3 kGy. As the radiation dose increased, the inactivation effect increased among all tested pathogens. After 3.0 kGy of gamma and electron beam irradiation, numbers of inoculated pathogens were reduced to below the detection limit (1 log CFU/g). The D 10 -values of E. coli O157:H7, S. Typhimurium, and L. monocytogenes in cookie dough treated with gamma rays were 0.53, 0.51, and 0.71 kGy, respectively, which were similar to those treated by electron beam with the same dose. Based on the D 10 -value of pathogens in cookie dough, L. monocytogenes showed more resistance to both treatments than did E. coli O157:H7 and S. Typhimurium. Color values and textural characteristics of irradiated cookie dough were not significantly (P > 0.05) different from the control. These results suggest that irradiation can be applied to control pathogens in ready-to-bake cookie dough products without affecting quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Dielectric barrier discharge atmospheric cold plasma inhibits Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus in Romaine lettuce.

    Science.gov (United States)

    Min, Sea C; Roh, Si Hyeon; Niemira, Brendan A; Sites, Joseph E; Boyd, Glenn; Lacombe, Alison

    2016-11-21

    The present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus (TV) on Romaine lettuce, assessing the influences of moisture vaporization, modified atmospheric packaging (MAP), and post-treatment storage on the inactivation of these pathogens. Romaine lettuce was inoculated with E. coli O157:H7, Salmonella, L. monocytogenes (~6logCFU/g lettuce), or TV (~2logPFU/g lettuce) and packaged in either a Petri dish (diameter: 150mm, height: 15mm) or a Nylon/polyethylene pouch (152×254mm) with and without moisture vaporization. Additionally, a subset of pouch-packaged leaves was flushed with O 2 at 5% or 10% (balance N 2 ). All of the packaged lettuce samples were treated with DACP at 34.8kV for 5min and then analyzed either immediately or following post-treatment storage for 24h at 4°C to assess the inhibition of microorganisms. DACP treatment inhibited E. coli O157:H7, Salmonella, L. monocytogenes, and TV by 1.1±0.4, 0.4±0.3, 1.0±0.5logCFU/g, and 1.3±0.1logPFU/g, respectively, without environmental modifications of moisture or gas in the packages. The inhibition of the bacteria was not significantly affected by packaging type or moisture vaporization (p>0.05) but a reduced-oxygen MAP gas composition attenuated the inhibition rates of E. coli O157:H7 and TV. L. monocytogenes continued to decline by an additional 0.6logCFU/g in post-treatment cold storage for 24h. Additionally, both rigid and flexible conventional plastic packages appear to be suitable for the in-package decontamination of lettuce with DACP. Published by Elsevier B.V.

  6. Listeria monocytogenes in Fresh Produce: Outbreaks, Prevalence and Contamination Levels

    Directory of Open Access Journals (Sweden)

    Qi Zhu

    2017-03-01

    Full Text Available Listeria monocytogenes, a member of the genus Listeria, is widely distributed in agricultural environments, such as soil, manure and water. This organism is a recognized foodborne pathogenic bacterium that causes many diseases, from mild gastroenteritis to severe blood and/or central nervous system infections, as well as abortion in pregnant women. Generally, processed ready-to-eat and cold-stored meat and dairy products are considered high-risk foods for L. monocytogenes infections that cause human illness (listeriosis. However, recently, several listeriosis outbreaks have been linked to fresh produce contamination around the world. Additionally, many studies have detected L. monocytogenes in fresh produce samples and even in some minimally processed vegetables. Thus L. monocytogenes may contaminate fresh produce if present in the growing environment (soil and water. Prevention of biofilm formation is an important control measure to reduce the prevalence and survival of L. monocytogenes in growing environments and on fresh produce. This article specifically focuses on fresh produce–associated listeriosis outbreaks, prevalence in growing environments, contamination levels of fresh produce, and associated fresh produce safety challenges.

  7. Prebiotic Oligosaccharides Potentiate Host Protective Responses against L. Monocytogenes Infection

    Directory of Open Access Journals (Sweden)

    Poyin Chen

    2017-12-01

    Full Text Available Prebiotic oligosaccharides are used to modulate enteric pathogens and reduce pathogen shedding. The interactions with prebiotics that alter Listeria monocytogenes infection are not yet clearly delineated. L. monocytogenes cellular invasion requires a concerted manipulation of host epithelial cell membrane receptors to initiate internalization and infection often via receptor glycosylation. Bacterial interactions with host glycans are intimately involved in modulating cellular responses through signaling cascades at the membrane and in intracellular compartments. Characterizing the mechanisms underpinning these modulations is essential for predictive use of dietary prebiotics to diminish pathogen association. We demonstrated that human milk oligosaccharide (HMO pretreatment of colonic epithelial cells (Caco-2 led to a 50% decrease in Listeria association, while Biomos pretreatment increased host association by 150%. L. monocytogenes-induced gene expression changes due to oligosaccharide pretreatment revealed global alterations in host signaling pathways that resulted in differential subcellular localization of L. monocytogenes during early infection. Ultimately, HMO pretreatment led to bacterial clearance in Caco-2 cells via induction of the unfolded protein response and eIF2 signaling, while Biomos pretreatment resulted in the induction of host autophagy and L. monocytogenes vacuolar escape earlier in the infection progression. This study demonstrates the capacity of prebiotic oligosaccharides to minimize infection through induction of host-intrinsic protective responses.

  8. Low prevalence of Listeria monocytogenes in cull sows and pork.

    Science.gov (United States)

    Wesley, Irene V; Larsen, Steven; Hurd, H Scott; McKean, James D; Griffith, Ronald; Rivera, Fernando; Nannapaneni, Ramakrishna; Cox, Mandy; Johnson, Michael; Wagner, Dean; de Martino, Mary

    2008-03-01

    The goal of this study was to determine the prevalence of Listeria monocytogenes in sows slaughtered at a single Midwestern plant on two occasions (trial 1, n = 179 sows; trial 2, n = 160 sows). Fecal samples collected antemortem (trial 1) as well as animal tissues, and carcass swabs collected at the abattoir (trials 1 and 2) were analyzed. Eight isolates of L. monocytogenes were recovered from five samples that represented 0.18% of the total samples (n = 2,775). In trial 1, L. monocytogenes was detected in a tonsil sample (0.6%; 1 positive of 181 tonsils), in a carcass (0.6%; 1 positive of 179 carcasses), which was sampled prior to the organic rinse, and in two chopped meat block samples (1.2%; 2 positive of 165 samples). In trial 2, L. monocytogenes was only detected in a single chopped meat block sample (0.15%; 1 positive of 688 total samples). These data indicate the low prevalence of L. monocytogenes in the cull sow.

  9. Deciphering the landscape of host barriers to Listeria monocytogenes infection.

    Science.gov (United States)

    Zhang, Ting; Abel, Sören; Abel Zur Wiesch, Pia; Sasabe, Jumpei; Davis, Brigid M; Higgins, Darren E; Waldor, Matthew K

    2017-06-13

    Listeria monocytogenes is a common food-borne pathogen that can disseminate from the intestine and infect multiple organs. Here, we used sequence tag-based analysis of microbial populations (STAMP) to investigate L monocytogenes population dynamics during infection. We created a genetically barcoded library of murinized L monocytogenes and then used deep sequencing to track the pathogen's dissemination routes and quantify its founding population ( N b ) sizes in different organs. We found that the pathogen disseminates from the gastrointestinal tract to distal sites through multiple independent routes and that N b sizes vary greatly among tissues, indicative of diverse host barriers to infection. Unexpectedly, comparative analyses of sequence tags revealed that fecally excreted organisms are largely derived from the very small number of L. monocytogenes cells that colonize the gallbladder. Immune depletion studies suggest that distinct innate immune cells restrict the pathogen's capacity to establish replicative niches in the spleen and liver. Finally, studies in germ-free mice suggest that the microbiota plays a critical role in the development of the splenic, but not the hepatic, barriers that prevent L. monocytogenes from seeding these organs. Collectively, these observations illustrate the potency of the STAMP approach to decipher the impact of host factors on population dynamics of pathogens during infection.

  10. Total Synthesis of Two 4, 5-Dioxo-seco-eudesmane Sesquiterpenes

    Institute of Scientific and Technical Information of China (English)

    Li Jing FANG; Chen Xi ZHANG; Jin Chun CHEN; Guo Jun ZHENG; Yu Lin LI

    2005-01-01

    A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γeudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from (+)-dihydrocarvone has been described. Avoiding expensive reagents, this highly economic method especially suits for the synthesis of 4, 5-seco-eudesman-type and ophianon-type sesquiterpenes with a double bond at position 11 and 12.

  11. The inoculation method affects colonization and performance of bacterial inoculant strains in the phytoremediation of soil contaminated with diesel oil.

    Science.gov (United States)

    Afzal, Muhammad; Yousaf, Sohail; Reichenauer, Thomas G; Sessitsch, Angela

    2012-01-01

    Plants in combination with microorganisms can remediate soils, which are contaminated with organic pollutants such as petroleum hydrocarbons. Inoculation of plants with degrading bacteria is one approach to improve remediation processes, but is often not successful due to the competition with resident microorganisms. It is therefore of high importance to address the persistence and colonization behavior of inoculant strains. The objective of this study was to determine whether the inoculation method (seed imbibement and soil inoculation) influences bacterial colonization, plant growth promotion and hydrocarbon degradation. Italian ryegrass was grown in non-sterilized soil polluted with diesel and inoculated with different alkane-degrading strains Pantoea sp. ITSI10, Pantoea sp. BTRH79 and Pseudomonas sp. MixRI75 individually as well as in combination. Inoculation generally had a beneficial effect on plant biomass production and hydrocarbon degradation, however, strains inoculated in soil performed better than applied by seed imbibement. Performance correlated with the colonization efficiency of the inoculated strains. The highest hydrocarbon degradation was observed in the treatment, in which all three strains were inoculated in combination into soil. Our study revealed that besides the degradation potential and competitive ability of inoculant strains the inoculation method plays an important role in determining the success of microbial inoculation.

  12. Application of an active alginate coating to control the growth of Listeria monocytogenes on poached and deli turkey products.

    Science.gov (United States)

    Juck, Greg; Neetoo, Hudaa; Chen, Haiqiang

    2010-09-01

    The relatively high prevalence of Listeria monocytogenes in ready-to-eat (RTE) turkey products is of great concern. The overall objective of this study was to develop antimicrobial edible coating formulations to effectively control the growth of this pathogen. The antimicrobials studied were nisin (500IU/g), Novagard CB 1 (0.25%), Guardian NR100 (500ppm), sodium lactate (SL, 2.4%), sodium diacetate (SD, 0.25%), and potassium sorbate (PS, 0.3%). These were incorporated alone or in binary combinations into five edible coatings: alginate, kappa-carrageenan, pectin, xanthan gum, and starch. The coatings were applied onto the surface of home-style poached and processed deli turkey discs inoculated with ~3log CFU/g of L. monocytogenes. The turkey samples were then stored at 22 degrees C for 7days. For poached and processed deli turkey, the coatings were found to be equally effective, with pectin being slightly less effective than the others. The most effective poached turkey treatments seemed to be SL (2.4%)/SD (0.25%) and Nisin (500IU/g)/SL (2.4%), which yielded final populations of 3.0 and 4.9log CFU/g respectively compared to the control which was 7.9log CFU/g. For processed deli turkey, the most effective antimicrobial treatments seemed to be Nisin (500IU/g)/SD (0.25%) and Nisin (500IU/g)/SL (2.4%) with final populations of 1.5 and 1.7log CFU/g respectively compared to the control which was 6.5log CFU/g. In the second phase of the study, home-style poached and store-purchased roasted (deli) turkey inoculated with the pathogen at a level of ~3log CFU/g were coated with alginate incorporating selected antimicrobial combinations and stored for 8weeks at 4 degrees C. Alginate coatings supplemented with SL (2.4%)/PS (0.3%) delayed the growth of L. monocytogenes with final counts reaching 4.3log CFU/g (home-style poached turkey) and 6.5log CFU/g (roasted deli turkey) respectively while the counts in their untreated counterparts were significantly higher (P<0.05) reaching 9

  13. Impact of Listeria Inoculation and Aerated Steam Sanitization on Volatile Emissions of Whole Fresh Cantaloupes.

    Science.gov (United States)

    Forney, Charles F; Fan, Lihua; Bezanson, Gregory S; Ells, Timothy C; LeBlanc, Denyse I; Fillmore, Sherry

    2018-04-01

    Rapid methods to detect bacterial pathogens on food and strategies to control them are needed to mitigate consumer risk. This study assessed volatile emissions from whole cantaloupe melons (Cucumis melo) as an indicator of Listeria contamination and in response to steam vapor decontamination. Cantaloupe were inoculated with Listeria innocua, a nonpathogenic surrogate for L. monocytogenes, then exposed to 85 °C steam for 240 s (4 min) followed by rapid chilling and storage for 0, 7, 10, or 14 days at 4, 7, or 10 °C. Volatile emissions from whole melons were collected on Carbopack B/Carboxen 1000 headspace collection tubes and analyzed by gas chromatography-mass spectroscopy following thermal desorption. Introduction of L. innocua to cantaloupe rind resulted in a reduction of aromatic compound emission. However, this response was not unique to Listeria contamination in that steam vapor treatment also reduced emission of these compounds. As well, steam vapor treatment diminished the number of viable Listeria and indigenous microflora while causing physiological injury to melon rind. Heat treatment had no significant effects on flesh firmness, color, titratable acidity, or soluble solids, but the production of typical aroma volatiles during postharvest ripening was inhibited. No unique volatile compounds were detected in Listeria contaminated melons. While changes in volatile emissions were associated with Listeria inoculation, they could not be differentiated from heat treatment effects. Results indicate that volatile emissions cannot be used as a diagnostic tool to identify Listeria contamination in whole cantaloupe melons. The detection of pathogen contamination on fresh produce is a continuing challenge. Using a nondestructive screening method, the presence of surrogate Listeria innocua on fresh whole cantaloupes was shown to alter the emissions of aromatic volatiles from whole cantaloupes. However, these altered emissions were not found to be unique to Listeria

  14. Listeria monocytogenes: Overview and Targeting Advances

    Directory of Open Access Journals (Sweden)

    Mostafa F.N. Abushahba

    2016-04-01

    Full Text Available Listeria monocytogenes is a serious foodborne zoonotic pathogen capable of causing gastroenteritis and severe systemic infections such as septicemia, meningitis or abortion in the infected individuals what is called listeriosis. The bacterium is reported as the third leading cause of death among the foodborne pathogens preceded by nontyphoidal Salmonella spp. and Toxoplasma gondii. The power to tolerate a wide range of temperatures is considered the most prominent trait distinguishing it from the other foodborne pathogens. Within the infected host, the bacteria harbor inside macrophages and jump from cell to another without leaving the safeguarding milieu of the host's cells utilizing a set of genes including hly (listeriolysin O, plcA (phosphatidylinositol-specific phospholipase c, plcB (phosphatidylcholine-phospholipase C and actA (actin-assembly inducing protein. In addition to the health concerns associated with antibiotics, treatment failure likely occurs among listeriosis-infected persons especially with the inability of most antibiotics to access intracellular replicative niches and achieve the optimum therapeutic concentrations within the infected cells. Recently, one novel choice, peptide nucleic acid (PNA, has been emerged to target this bacterium as a model of targeting intracellular pathogens with anti-sense agents. PNA is a one of the DNA analogues which works via specific inhibition of bacterial gene expression.

  15. Ion channel regulation by phosphoinositides analyzed with VSPs – PI(4,5P2 affinity, phosphoinositide selectivity, and PI(4,5P2 pool accessibility

    Directory of Open Access Journals (Sweden)

    Alexandra eRjasanow

    2015-06-01

    Full Text Available The activity of many proteins depends on the phosphoinositide (PI content of the membrane. E.g., dynamic changes of the concentration of PI(4,5P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids.Voltage-sensitive phosphatases (VSPs turn over PI(4,5P2 to PI(4P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5P2. Because cellular PI(4,5P2 is resynthesized rapidly, steady state PI(4,5P2 changes with the degree of VSP activation and thus depends on membrane potential.Here we show that titration of endogenous PI(4,5P2 with Ci-VSP allows for the quantification of relative PI(4,5P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K+ channels to Ci-VSP allowed for comparison of PI(4,5P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5P2 and PI(4P was insensitive to VSP.Surprisingly, despite comparable PI(4,5P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5P2 that differ in their accessibility to PLC and VSPs.

  16. Prevalence and antimicrobial susceptibility of Listeria monocytogenes on chicken carcasses in Bandung, Indonesia.

    Science.gov (United States)

    Sugiri, Yoni Darmawan; Gölz, Greta; Meeyam, Tongkorn; Baumann, Maximilian P O; Kleer, Josef; Chaisowwong, Warangkhana; Alter, Thomas

    2014-08-01

    This study was conducted to determine the prevalence and quantify the number of Listeria monocytogenes in fresh chicken carcasses sold in traditional markets and supermarkets in Bandung, West Java, Indonesia, and to determine the antimicrobial resistance patterns of the isolated L. monocytogenes strains. The overall prevalence of L. monocytogenes in chicken carcasses was 15.8% (29/184). When comparing samples from traditional markets and supermarkets, no significant difference in the L. monocytogenes prevalence was detectable (15.2 versus 16.3%). Of the samples, 97.3% had L. monocytogenes counts study were grouped into the molecular serogroup IIb, comprising the serovars 1/2b, 3b, and 7.

  17. Behaviour of Listeria monocytogenes in artisanal raw milk Pecorino Umbro cheese: a microbiological challenge test

    Directory of Open Access Journals (Sweden)

    Roberta Ortenzi

    2015-09-01

    Full Text Available In the present study, a microbiological challenge test in artificially contaminated raw milk Pecorino Umbro cheese during cheese-making was carried out. Raw ewe milk was contaminated by a suspension of particular Listeria monocytogenes strains. The number of L. monocytogenes and L. monocytogenes dynamic growth were evaluated during cheese-making and storage. A significant decrease of the viable count of L. monocytogenes was observed during ripening and L. monocytogenes viable count was below the limit of quantification during storage. The results show that the product is unable to support the growth of the pathogen.

  18. Microbiological criteria for Listeria monocytogenes in foods under special consideration of risk assessment approaches

    DEFF Research Database (Denmark)

    Nørrung, Birgit

    2000-01-01

    This paper shortly summarizes data related to risk assessment of Listeria monocytogenes. From available data on risk assessment, it is concluded that the levels of L. monocytogenes consumed is an important factor affecting the incidence of listeriosis. Foods that do not support the growth of L....... monocytogenes are unlikely to be a source of listeriosis, whereas foods that support the growth to high levels, should be the target of risk management efforts. Based on current epidemiological information from several countries, a concentration of L. monocytogenes not exceeding 100/g of food at the time...... of L. monocytogenes in the food during prevailing storage and distribution conditions is needed....

  19. Early trigeminal nerve involvement in Listeria monocytogenes rhombencephalitis

    DEFF Research Database (Denmark)

    Karlsson, William K; Harboe, Zitta Barrella; Roed, Casper

    2017-01-01

    dysfunction on that side. In addition, we identified another 120 cases of Listeria rhombencephalitis following a systematic review. Cranial nerves VII, V, IX, and X, respectively, medulla oblongata, cerebellum and pons, were the most frequently involved brain structures. The present clinical and radiological...... findings corroborate earlier data from animal experiments, indicating that L. monocytogenes may be capable of retrograde intra-axonal migration along the cranial nerves. We suggest that in a subset of patients with rhombencephalitis L. monocytogenes enters the cerebellopontine angle through the trigeminal......Listeria monocytogenes is associated with rhombencephalitis. However, the exact mechanisms of brainstem invasion remains poorly understood. Here, we demonstrate clinical and radiological data suggesting that Listeria may invade the brainstem via the trigeminal nerve. Three females (41, 64 and 70...

  20. COMPARISON OF TWO METHODS FOR THE DETECTION OF LISTERIA MONOCYTOGENES

    Directory of Open Access Journals (Sweden)

    G. Tantillo

    2013-02-01

    Full Text Available The aim of this study was to compare the performance of the conventional methods for detection of Listeria monocytogenes in food using media Oxford and ALOA (Agar Listeria acc. to Ottaviani & Agosti in according to the ISO 11290-1 to a new chromogenic medium “CHROMagar Listeria” standardized in 2005 AFNOR ( CHR – 21/1-12/01. A total of 40 pre-packed ready-to-eat food samples were examined. Using two methods six samples were found positive for Listeria monocytogenes but the medium “CHROMagar Listeria” was more selective in comparison with the others. In conclusion this study has demonstrated that isolation medium able to target specifically the detection of L. monocytogenes such as “CHROMagar Listeria” is highly recommendable because of that detection time is significantly reduced and the analysis cost is less expensive.

  1. Role of Extracellular DNA during Biofilm Formation by Listeria monocytogenes

    DEFF Research Database (Denmark)

    Harmsen, Morten; Lappann, Martin; Knøchel, S

    2010-01-01

    (eDNA) may be the only central component of the biofilm matrix and that it is necessary for both initial attachment and early biofilm formation for 41 L. monocytogenes strains that were tested. DNase I treatment resulted in dispersal of biofilms, not only in microtiter tray assays but also in flow......Listeria monocytogenes is a food-borne pathogen that is capable of living in harsh environments. It is believed to do this by forming biofilms, which are surface-associated multicellular structures encased in a self-produced matrix. In this paper we show that in L. monocytogenes extracellular DNA...... cell biofilm assays. However, it was also demonstrated that in a culture without eDNA, neither Listeria genomic DNA nor salmon sperm DNA by itself could restore the capacity to adhere. A search for additional necessary components revealed that peptidoglycan (PG), specifically N-acetylglucosamine (NAG...

  2. Listeria spp., y L. monocytogenes EN LECHE CRUDA DE CABRA

    Directory of Open Access Journals (Sweden)

    Yolanda Albarracín C

    2008-08-01

    Full Text Available Objective. To test non-pasteurized goat’s milk from the village of ‘la Garita’, Northern Santander, for Listeria monocytogenes. Material and methods. 90 samples of non-pasteurized goat’s milk were obtained over a 4 month period; pH and temperature of each sample were measured. The INVIMA technique was used to isolate L. monocytogenes; the species was confirmed by PCR. Results. The study showed that eight goat milk providers of the zone neither had refrigeration nor pasteurized the milk. The prevalence of L. monocytogenes was 3%; 15% of the samples had other species of Listeria. The milk obtained from this zone contained the pathogen that may cause listeriosis in children less than 5 years of age, pregnant women, adults and immunologically compromised patients. Conclusions. This study shows the occurrence of this pathogen in goat’s milk and identified areas of risk for those people who drink goat’s milk.

  3. Review of Prosthetic Joint Infection from Listeria monocytogenes.

    Science.gov (United States)

    Bader, Gilbert; Al-Tarawneh, Mohammed; Myers, James

    2016-12-01

    Prosthetic joint infection from Listeria monocytogenes is rare. We decided to shed light on this illness and review the reported cases to better understand its characteristics. We conducted a comprehensive review of the English literature using PubMed. We also included one case that we had managed. We found 25 cases of prosthetic joint infection from L. monocytogenes reported individually and a retrospective study of 43 cases of joint and bone listerial infection, including 34 with prosthetic joint infection, conducted in France. We have described their clinical and para-clinical features and tried to elaborate on the pathophysiology, treatment, and prevention. Prosthetic joint infection from L. monocytogenes is mainly late. Systemic inflammation may be absent. Although rare, it must be suspected in patients at high risk for both prosthetic joint and listerial infections. In addition, those patients must be instructed on appropriate preventive measures.

  4. Listeria monocytogenes response regulators important for stress tolerance and pathogenesis

    DEFF Research Database (Denmark)

    Kallipolitis, B H; Ingmer, H

    2001-01-01

    Environmental sensing by two-component signal transduction systems is likely to play a role for growth and survival of Listeria monocytogenes both during transmission in food products and within a host organism. Two-component systems typically consist of a membrane-associated sensor histidine...... kinase and a gene regulatory protein, the response regulator (RR). We have identified seven putative RR genes in L. monocytogenes LO28 by PCR using degenerate oligonucleotide primers. By insertional inactivation we obtained data suggesting that three of the putative RRs contribute to the pathogenicity...... of L. monocytogenes in mice. Strikingly, the mutants that were attenuated in virulence also had a decreased ability to grow in the presence of various stress conditions potentially encountered in an infection process. Thus, our data point to a connection between the ability of the putative two...

  5. Listeria monocytogenes in retailed raw chicken meat in Turkey.

    Science.gov (United States)

    Siriken, Belgin; Ayaz, Naim Deniz; Erol, Irfan

    2014-01-01

    The objectives of this study were, to find the prevalence and antimicrobial resistance of L. monocytogenes from a total of 116 chicken meat samples including 50 carcasses and 66 meat parts marketed in Turkey between 2008 and 2009 using immunomagnetic separation (IMS) based cultivation technique, to detect the hlyA gene for the verification of the isolates by PCR, and to identify the genoserotypes of the L. monocytogenes isolates by multiplex PCR assay. In the study, 51 L. monocytogenes colonies were isolated from 34 (29.3%) chicken meat samples (eleven [22.0%] carcasses and 23 [34.8%] pieces of meat) by IMS based cultivation technique and confirmed by PCR. According to the multiplex PCR results, all the 51 isolates were identified as genoserotype IIa (1/2a or 3a). L. monocytogenes isolates were also tested for their susceptibility to eight antibiotic (gentamicin, vancomycin, chloramphenicol, streptomycin, tetracycline, ampicillin, penicillin G, erythromycin) agents using the disk diffusion method. 14 isolates (27.45%) were susceptible to all eight antimicrobials drugs tested and the remaining 37 isolates (72.54%) were resistant to gentamicin (one isolate, 1.96%), vancomycin (four isolates, 7.84%), penicillin G (six isolates, 11.76%), streptomycin (nine isolates, 17.64%; resistant or intermediate), tetracycline (seven isolates, 13.72%) and ampicillin (six isolates, 11.76%). This study showed that antimicrobial resistance is not highly prevalent in L. monocytogenes isolated from chicken carcasses and pieces of meat. The presence of L. monocytogenes in chicken samples suggests an importance of this pathogen in chicken.

  6. Aerosol studies with Listeria innocua and Listeria monocytogenes.

    Science.gov (United States)

    Zhang, Guodong; Ma, Li; Oyarzabal, Omar A; Doyle, Michael P

    2007-08-01

    Aerosol studies of Listeria monocytogenes in food processing plants have been limited by lack of a suitable surrogate microorganism. The objective of this study was to investigate the potential of using green fluorescent protein-labeled strains of Listeria innocua as a surrogate for L. monocytogenes for aerosol studies. These studies were conducted in a laboratory bioaerosol chamber and a pilot food-processing facility. Four strains of L. innocua and five strains of L. monocytogenes were used. In the laboratory chamber study, Listeria cells were released into the environment at two different cell numbers and under two airflow conditions. Trypticase soy agar (TSA) plates and oven-roasted breasts of chicken and turkey were placed in the chamber to monitor Listeria cell numbers deposited from aerosols. A similar experimental design was used in the pilot plant study; however, only L. innocua was used. Results showed that L. monocytogenes and L. innocua survived equally well on chicken and turkey breast meats and TSA plates. No-fan and continuous fan applications, which affected airflow, had no significant effect on settling rates of aerosolized L. monocytogenes and L. innocua in the bioaerosol chamber or L. innocua in the pilot plant study. Listeriae cell numbers in the air decreased rapidly during the first 1.5 h following release, with few to no listeriae detected in the air at 3 h. Aerosol particles with diameters of 1 and 2 microM correlated directly with the number of Listeria cells in the aerosol but not with particles that were 0.3, 0.5, and 5 microM in diameter. Results indicate that L. innocua can be used as a surrogate for L. monocytogenes in an aerosol study.

  7. Spontaneous Loss of Virulence in Natural Populations of Listeria monocytogenes.

    Science.gov (United States)

    Maury, Mylène M; Chenal-Francisque, Viviane; Bracq-Dieye, Hélène; Han, Lei; Leclercq, Alexandre; Vales, Guillaume; Moura, Alexandra; Gouin, Edith; Scortti, Mariela; Disson, Olivier; Vázquez-Boland, José A; Lecuit, Marc

    2017-11-01

    The pathogenesis of Listeria monocytogenes depends on the ability of this bacterium to escape from the phagosome of the host cells via the action of the pore-forming toxin listeriolysin O (LLO). Expression of the LLO-encoding gene ( hly ) requires the transcriptional activator PrfA, and both hly and prfA genes are essential for L. monocytogenes virulence. Here, we used the hemolytic activity of LLO as a phenotypic marker to screen for spontaneous virulence-attenuating mutations in L. monocytogenes Sixty nonhemolytic isolates were identified among a collection of 57,820 confirmed L. monocytogenes strains isolated from a variety of sources (0.1%). In most cases (56/60; 93.3%), the nonhemolytic phenotype resulted from nonsense, missense, or frameshift mutations in prfA Five strains carried hly mutations leading to a single amino acid substitution (G299V) or a premature stop codon causing strong virulence attenuation in mice. In one strain, both hly and gshF (encoding a glutathione synthase required for full PrfA activity) were missing due to genomic rearrangements likely caused by a transposable element. The PrfA/LLO loss-of-function (PrfA - /LLO - ) mutants belonged to phylogenetically diverse clades of L. monocytogenes , and most were identified among nonclinical strains (57/60). Consistent with the rare occurrence of loss-of-virulence mutations, we show that prfA and hly are under purifying selection. Although occurring at a low frequency, PrfA - /LLO - mutational events in L. monocytogenes lead to niche restriction and open an evolutionary path for obligate saprophytism in this facultative intracellular pathogen. Copyright © 2017 Maury et al.

  8. Synthesis and muscarinic receptor pharmacology of a series of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridine bioisosteres of arecoline

    DEFF Research Database (Denmark)

    Pedersen, H; Bräuner-Osborne, H; Ball, R G

    1999-01-01

    A series of O- and ring-alkylated derivatives of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridin-3-ol was synthesized via treatment of appropriately substituted 4-benzylamino-1,2,5,6-tetrahydropyridine-3-carboxamides with hydrogen sulfide and subsequent ring closure by oxidation with bromine. The mus...

  9. Listeria monocytogenes in poultry and poultry products: Epidemiological investigations in seven Danish abattoirs

    DEFF Research Database (Denmark)

    Ojeniyi, B.; Wegener, Henrik Caspar; Jensen, N.E.

    1996-01-01

    Listeria monocytogenes was isolated from 11/236 (4 . 7%) caecal samples from parent flocks, providing broilers to the abattoirs investigated. Caecal samples from 2078 broilers representing 90 randomly selected broiler flocks were negative for L. monocytogenes. A total of 3080 samples from seven...... abattoirs including poultry processing line samples, and final products were also examined for L. monocytogenes. Listeria monocytogenes was isolated in 0 . 3% to 18 . 7% of the samples collected in the different abattoirs. Epidemiological typing of 247 L. monocytogenes isolates, including serotyping, phage...... isolates of L. monocytogenes since only 120/247 (48 . 6%) isolates were typable by phage typing and 230/247 (93 . 1%) L. monocytogenes belonged to serotype 01 while 6/247 (2 . 4%) belonged to 04. The discovery of a few dominating clones in each abattoir might indicate an endemic occurrence of L...

  10. Necessity of mycorrhizal re-inoculation in the transplantation of banana in areas with precedent of inoculated canavalia with AMF

    Directory of Open Access Journals (Sweden)

    Jaime Enrique Simó González

    2016-07-01

    Full Text Available From being the banana, a mycotrophic crop and previous results on the potential of green manure inoculated as a way to mycorrhizal economic crops, this work was developed in order to assess whether a precedent Canavalia ensiformis cultivation, inoculated with efficient strains of arbuscular mycorrhizal fungi (AMF inoculation, it is necessary the banana inoculation, ‘FHIA-18’ (AAAB cultivar in the transplant field. Four treatments were evaluated: a control without application of fertilizers and other organic-mineral fertilizers (100% FOM, both without canavalia and two other treatments that are used above canavalia inoculated AMF and half also received organic-mineral fertilizer applications: (50% FOM, one of which, the banana was reinoculated in the transplant field and the other one not. The experimental design used, was randomized blocks, with four replications. The experiment ended after three productive cycles (mother plant, stems 1 and 2. Canavalia inoculated treatments and 50 % of FOM, guaranteed high yields and satisfactory nutritional content similar to that received 100 % of FOM and significantly higher than those obtained with the control treatment. This together with the values of colonization percentages and pores at both high and inoculated treatments were no significant differences between them, indicated not only the effectiveness of mycorrhizal inoculation but rather green manure inoculation was successful to inoculate bananas and re-inoculation of the same was not needed on the transplant.

  11. Variations in virulence between different electrophoretic types of Listeria monocytogenes

    DEFF Research Database (Denmark)

    Nørrung, Birgit; Andersen, Jens Kirk

    2000-01-01

    A total of 245 strains of Listeria monocytogenes, representing 33 different electrophoretic types (ETs), were examined quantitatively for haemolytic activity. No significant difference was observed in the mean haemolytic activity between different ETs. Eighty four out of 91 strains examined were...... compared with 3.64 among food isolates). The explanation for this may be that more virulent strains are more prone to cause human infection. It is, however, also possible that strains oft. monocytogenes may become more virulent while multiplying in a living organism compared with multiplying in foods....

  12. Ca2+-mediated generation of inositol 1,4,5-triphosphate and inositol 1,3,4,5-tetrakisphosphate in pancreatic islets. Studies with K+, glucose, and carbamylcholine

    International Nuclear Information System (INIS)

    Biden, T.J.; Peter-Riesch, B.; Schlegel, W.; Wollheim, C.B.

    1987-01-01

    The role of Ca2+ in the generation of inositol phosphates was investigated using rat pancreatic islets after steady state labeling with myo-[2- 3 H]inositol. Depolarizing K+ concentrations (24 mM) evoked early (2 s) increases in inositol 1,4,5-trisphosphate (Ins-1,4,5-P3) and inositol 1,3,4,5-tetrakisphosphate (Ins-1,3,4,5-P4) as measured by high performance anion-exchange chromatography. The increase in Ins-1,4,5-P3 was transient and was followed by a more pronounced rise in Ins-1,3,4-P3. These effects were dependent on the presence of extracellular Ca2+ but were not secondary to release of either neurotransmitters or metabolites of arachidonic acid. K+ also promoted the breakdown of phosphatidylinositol 4,5-bisphosphate (PtdIns-4,5-P2) and of the other phosphoinositides. Glucose (16.7 mM) was less marked in its effects but still promoted rapid increases in Ins-1,3,4,5-P4 (2 s) and Ins-1,4,5-P3 (10 s) and a slower rise in Ins-1,3,4-P3 (30 s). The levels of all three metabolites rose steadily over 10 min stimulation. These responses to glucose could be largely, although not entirely, inhibited by depletion of extracellular Ca2+ or by Ca2+ channel blockade with verapamil (20 microM). Carbamylcholine (0.5 mM) was the most potent stimulus used evoking early rises in Ins-1,4,5-P3 and Ins-1,3,4,5-P4 (2 s) followed by Ins-1,3,4-P3 (10 s), effects which were only partially dependent on extracellular Ca2+. The results suggest that a Ca2+-mediated PtdIns-4,5-P2 hydrolysis accounts for most of the Ins-1,4,5-P3 generated in response to glucose but not carbamylcholine

  13. 60-day aging requirement does not ensure safety of surface-mold-ripened soft cheeses manufactured from raw or pasteurized milk when Listeria monocytogenes is introduced as a postprocessing contaminant.

    Science.gov (United States)

    D'Amico, Dennis J; Druart, Marc J; Donnelly, Catherine W

    2008-08-01

    Because of renewed interest in specialty cheeses, artisan and farmstead producers are manufacturing surface-mold-ripened soft cheeses from raw milk, using the 60-day holding standard (21 CFR 133.182) to achieve safety. This study compared the growth potential of Listeria monocytogenes on cheeses manufactured from raw or pasteurized milk and held for > 60 days at 4 degrees C. Final cheeses were within federal standards of identity for soft ripened cheese, with low moisture targets to facilitate the holding period. Wheels were surface inoculated with a five-strain cocktail of L. monocytogenes at approximately 0.2 CFU/ cm2 (low level) or 2 CFU/cm2 (high level), ripened, wrapped, and held at 4 degrees C. Listeria populations began to increase by day 28 for all treatments after initial population declines. From the low initial inoculation level, populations in raw and pasteurized milk cheese reached maximums of 2.96 +/- 2.79 and 2.33 +/- 2.10 log CFU/g, respectively, after 60 days of holding. Similar growth was observed in cheese inoculated at high levels, where populations reached 4.55 +/- 4.33 and 5.29 +/- 5.11 log CFU/g for raw and pasteurized milk cheeses, respectively. No significant differences (P milk types. Independent of the milk type, cheeses held for 60 days supported growth from very low initial levels of L. monocytogenes introduced as a postprocess contaminant. The safety of cheeses of this type must be achieved through control strategies other than aging, and thus revision of current federal regulations is warranted.

  14. Nutrient Digestibility and Performances of Frisian Holstein Calves Fed with Pennisetum purpureum and Inoculated with Buffalo’s Rumen Bacteria

    Directory of Open Access Journals (Sweden)

    I. Prihantoro

    2014-12-01

    Full Text Available Buffalo’s rumen bacteria (BRB are potential in digesting fiber feed. BRB already adapted well with low quality forages and agricultural byproducts. The aim of this study was to determine the effect of buffalo’s rumen bacteria (BRB consortium inoculated into preweaning Frisian Holstein calves on nutrient digestibility, physiological status, mineral uptake, and blood profile. This study used 14 isolates of bacteria isolated from rumen fluid of four local buffalos. The research units consisted of seven Frisian Holstein calves at two weeks old with the average body weight of 43.6±4.5 kg. Calves were inoculated with 20 mL of buffalo’s rumen bacteria isolates [4.56 x 109 cfu/mL] every morning for 10 weeks. The calves were divided into two groups i.e., three calves received bacterial inoculation and four calves without any inoculation. The variables which were analyzed in the preweaning and weaning period were feed intake, digestibility, average daily gain (ADG, feed conversion ratio (FCR, rumen fermentation characteristics, body weight, physiological status, blood profile, and mineral status. Data were analyzed statistically using t-test. The results showed that inoculation of buffalo’s rumen bacteria into Frisian Holstein calves effectively increased feed intake, characteristics of leukocytes and neutrophils, and cobalt (Co uptake during the weaning period. Inoculation of rumen bacteria improved rumen pH during preweaning and weaning periods. Inoculation of rumen bacteria also had no negative effects on digestibility, feed conversion (FCR, average daily gain (ADG, and physiological status.

  15. Overlevingsstrategieën Listeria monocytogenes bij lage temperatuur

    NARCIS (Netherlands)

    Wemekamp-Kamphuis, H.H.; Abee, T.

    2004-01-01

    Listeria monocytogenes is an important food-borne pathogen that may cause severe infections in humans. Many outbreaks caused by this organism have been associated with ready-to-eat foods wich may have undergone some form of minimal processing, or have been contaminated after processing. Ready-to-eat

  16. Listeria monocytogenes serotype prevalence and biodiversity in diverse food products.

    Science.gov (United States)

    Hadjilouka, Agni; Andritsos, Nikolaos D; Paramithiotis, Spiros; Mataragas, Marios; Drosinos, Eleftherios H

    2014-12-01

    The aim of this study was to assess serotype prevalence and biodiversity of Listeria monocytogenes strains isolated from diverse food products, i.e., minced pork, fruits, and vegetables. Three hundred twenty-six samples previously purchased from supermarkets and street markets within the Athens area were studied for L. monocytogenes prevalence. A total of 121 strains were isolated from the 36 samples that were positive for L. monocytogenes. Serotyping was performed with multiplex PCR, and biodiversity was assessed with random amplified polymorphic DNA (RAPD) PCR analysis using M13, UBC155, and HLWL85 as primers and with repetitive element palindromic (rep) PCR analysis using (GTG)5 as the primer. The majority (17 of 22) of the contaminated minced pork samples contained strains identified as serotype 1/2a, either alone or in combination with strains belonging to serotypes 1/2b, 4a, 4c, or 4ab. However, all L. monocytogenes isolates from fruits and vegetables belonged to serotype 4b. Rep-PCR provided better differentiation of the isolates than did RAPD PCR and resulted in discrimination of the isolates into a larger number of unique profiles. Complete differentiation was achieved only with the combination of these subtyping techniques.

  17. Listeria monocytogenes repellence by enzymatically modified PES surfaces

    NARCIS (Netherlands)

    Veen, van der S.; Nady, N.; Franssen, M.C.R.; Zuilhof, H.; Boom, R.M.; Abee, T.; Schroën, C.G.P.H.

    2015-01-01

    : The effect of enzyme-catalyzed modification of poly(ethersulfone) (PES) on the adhesion and biofilm formation of two Listeria monocytogenes strains is evaluated under static and dynamic flow conditions. PES has been modified with gallic acid, ferulic acid and 4-hydroxybenzoic acid. The surfaces

  18. LISTERIA MONOCYTOGENES IN THE CONTEXT OF THE NEW COMMUNITY REGULATIONS

    Directory of Open Access Journals (Sweden)

    A. Bragagnolo

    2008-02-01

    Full Text Available In recent years in the countries of the European Union have occurred profound and radical changes regarding the safety and hygiene of foodstuffs. The aim of this work is to highlight the significant changes made by the recent legislation in the control of Listeria monocytogenes.

  19. Influence of temperature on alkali stress adaptation in Listeria monocytogenes

    Science.gov (United States)

    Listeria monocytogenes cells may induce alkali stress adaptation when exposed to sublethal concentrations of alkaline cleaners and sanitizers that may be frequently used in the food processing environment. In the present study, the effect of temperature on the induction and the stability of such alk...

  20. Activity of daptomycin against Listeria monocytogenes isolates from cerebrospinal fluid

    NARCIS (Netherlands)

    Spanjaard, Lodewijk; Vandenbroucke-Grauls, Christina M. J. E.

    2008-01-01

    We tested the activity of daptomycin against 76 Listeria monocytogenes isolates from cerebrospinal fluid by broth dilution and Etest methods. For the broth dilution method, the MIC range was 1.0 to 8.0 and the MIC at which 90% of the isolates tested were inhibited (MIC(90)) was 4.0 mg/liter. For the

  1. Listeria monocytogenes response regulators important for stress tolerance and pathogenesis

    DEFF Research Database (Denmark)

    Kallipolitis, B. H.; Ingmer, H.

    2001-01-01

    of L. monocytogenes in mice. Strikingly, the mutants that were attenuated in virulence also had a decreased ability to grow in the presence of various stress conditions potentially encountered in an infection process. Thus, our data point to a connection between the ability of the putative two...

  2. Formation of biofilm by strains of Listeria monocytogenes isolated ...

    African Journals Online (AJOL)

    Quantification of biofilm formation by 40 Listeria monocytogenes strains from wara soft cheese and its processing environment was assessed on glass vials surfaces. Attachement to glass surface was quantified using a crystal violet binding assay. All the 40 strains produced biofilms after 48 and 72 h incubation at 37oC.

  3. Pathogenic potential of Listeria monocytogenes isolated from cattle ...

    African Journals Online (AJOL)

    Listeria monocytogenes is an opportunistic food-borne pathogen causing listeriosis especially among immune-compromised persons. Its high rate of morbidity and mortality has classed the organism among the top watch list in foods. It is known to produce several virulence factors which aid its survival in harsh conditions ...

  4. Carrier status for Listeria monocytogenes and other Listeria species ...

    African Journals Online (AJOL)

    Background: Listeria organisms are documented to be zoonotic; one of the sources of infection is the domestic fowl where it could occur as in apparent infection. The carriage of Listeria monocytogenes and other Listeria in indigenous birds has not been documented in Kenya. Objective: To establish whether healthy looking ...

  5. Prevalence and antibiotic susceptibility of Listeria monocytogenes in ...

    African Journals Online (AJOL)

    One hundred and ninety two raw milk samples were collected from lactating cows identified in Fulani herds and small scale dairy farms within Sokoto metropolis in order to investigate the presence and determine the antibiotic susceptibility of Listeria monocytogenes in the milk. Selective culture and identification method ...

  6. Investigation into the fate of C-14-labelled xenobiotics(naphthalene, phenanthrene, 2,4,5,2 ',4',5 '-hexachlorobiphenyl, octachlorostyrene) in Bermudian corals

    OpenAIRE

    Solbakken, Jan Erik; Knap, A.H.; Sleeter, T.D.; Searle, C.E.; Palmork, Karsten H.

    1983-01-01

    Uptake and elimination of 4 labelled lipid-soluble xenobiotics (naphthalene, phenanthrene, 2,4,5,2',4',5'-hexachlorobiphen(yPlC B), octachlorostyrene) were studied in 19 anthozoans and 1 hydrozoan common to Bermudian waters. The concentration of radioactiv~ty In the tissues was determined using liquid scintillation counting. All organisms tested took up radioactivity from the water. However, elimination rates were very slow compared to those of other marine organisms. Naphthale...

  7. Urban prevalence of Listeria spp. and Listeria monocytogenes in public lavatories and on shoe soles of facility patrons in the European capital city Vienna.

    Science.gov (United States)

    Schoder, D; Schmalwieser, A; Szakmary-Brändle, K; Stessl, B; Wagner, M

    2015-05-01

    The aim of this study was to determine the prevalence of Listeria spp. and Listeria monocytogenes (L. monocytogenes) in urban public lavatories and on shoe soles of facility patrons in a European capital city. More than 91% of all municipal public lavatories in Vienna close to public hubs were included in this study. Overall, 373 swab samples of public lavatories and shoes of facility patrons were enriched, according to ISO 11290-1. Listeria monocytogenes isolates were subtyped using pulsed-field gel electrophoresis. A total of 24 samples were positive for Listeria spp., yielding an overall prevalence of 6.4% (24/373). Listeria monocytogenes was found in 2.1% (8/373) of all samples. Swabs from lavatories in parks, container lavatories and lavatories at markets had the highest prevalences of 20.7% (6/29), 20% (2/10) and 12.5% (1/8) Listeria spp., respectively. These detection rates were statistically significantly higher than those associated with lavatories in shopping centres (P = 0.003, P = 0.002, P = 0.02) and at public transport locations (P = 0.0004, P = 0.005, P = 0.02). Shoes sampled at Christmas markets showed the highest Listeria spp. and L. monocytogenes prevalences of 80% (4/5) and 40% (2/5), respectively. With regard to shoe type, Listeria spp. detection rates were 14.3% (3/21; winter boots), 13.3% (2/15; hiking boots), sport shoes (5.9%; 2/34) and brogues (5.1%; 4/79). No Listeria spp. were found on shoe soles that had smooth treads (0/76), while Listeria spp. were detected on 19.5% (8/41) of medium depth tread shoe types and on 9.4% (3/32) of deep tread shoes. These data suggest that soil environment is still one of the most important reservoirs for the foodborne pathogen L. monocytogenes. © 2014 Blackwell Verlag GmbH.

  8. Co-inoculation effects of Bradyrhizobium japonicum and ...

    African Journals Online (AJOL)

    Co-inoculation effects of Bradyrhizobium japonicum and Azospirillum sp. on competitive nodulation and rhizosphere eubacterial community structures of soybean under rhizobia-established soil conditions.

  9. Prevalence of Listeria monocytogenes in poultry production in France.

    Science.gov (United States)

    Chemaly, Marianne; Toquin, Marie-Therese; Le Nôtre, Yolene; Fravalo, Philippe

    2008-10-01

    This study aimed to update and create a data set from laying hens and broilers regarding contamination by Listeria monocytogenes. Two hundred laying-hen flocks were sampled, with 88 flocks reared in cages and 112 reared on the floor. One hundred forty-five broiler flocks were sampled, with 85 conventional and 60 free-range flocks. A total of 774 and 725 samples were analyzed from laying hens and broilers, respectively. L. monocytogenes was detected in 31 of 200 flocks, yielding an estimated prevalence of 15.5% in laying-hen flocks. Among positive flocks, there appeared a significant (P = 0.004) difference between caged and floor-reared hens, with a higher detection in dust samples from floor-reared hens. In positive caged hen flocks, significant (P = 0.028) differences between dust and fecal samples appeared, with a higher detection in feces than in dust samples. In broiler flocks, L. monocytogenes was isolated in 46 of 145 flocks, yielding an estimated prevalence of 32% (28% in conventional flocks versus 37% in the free-range flocks). L. monocytogenes was isolated in samples taken from conventional flocks with a lower frequency than in free-range flocks (13 versus 18%, respectively). The serotyping of L. monocytogenes strains showed that the majority belonged to type 1/2a in laying-hen flocks (74.3%) and in broiler flocks (40.5%). A significant difference (P = 0.007) between laying hens and broilers was shown for serogroup 4 and for serovar 1/2b (P = 0.007); these serogroups were more prevalent in broilers (40%) than in laying hens (5.7%).

  10. Gene Transcription and Virulence Potential of Listeria monocytogenes Strains After Exposure to Acidic and NaCl Stress

    DEFF Research Database (Denmark)

    Olesen, Inger; Vogensen, Finn Kvist; Jespersen, Lene

    2009-01-01

    transcription were observed both after exposure to shock (six genes) and after long-term adaptation to stress (18 genes). In the shock experiments, a transient induction of clpC and clpE was seen for both strains, while transient induction of sigB, inlA, and inlB was observed for strain 4140 only; actA was only...... induced in EGD-e after NaCl shock. The longterm stress experiments were included to imitate the stress conditions encountered by L. monocytogenes when present in food products. Long-term adaptation of EGD-e to acidic stress induced transcription of iap and repressed flaA, while genes related to stress......Gene transcription and virulence potential of two strains of Listeria monocytogenes, EGD-e and 4140, were compared by quantitative real-time polymerase chain reaction and in a Caco-2 in vitro model after exposure to acidic (pH 5.5) and NaCl (4.5% w=v) stress. Strain-dependent differences in gene...

  11. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Czech Academy of Sciences Publication Activity Database

    Janoušková, Martina; Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Roč. 12, č. 7 (2017), s. 1-21, č. článku e0181525. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LH14285 Institutional support: RVO:67985939 ; RVO:61389030 Keywords : inoculation * arbuscular mycorrhiza * community Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEB-Q) OBOR OECD: Plant sciences, botany; Plant sciences, botany (UEB-Q) Impact factor: 2.806, year: 2016

  12. Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

    Energy Technology Data Exchange (ETDEWEB)

    Gumus, Tuncay [Department of Food Engineering, Faculty of Agriculture, Namik Kemal University, 59030 Tekirdag (Turkey); Sukru Demirci, A; Murat Velioglu, H; Velioglu, Serap D; Yilmaz, Ismail [Department of Food Engineering, Faculty of Agriculture, Namik Kemal University, 59030 Tekirdag (Turkey); Sagdic, Osman [Department of Food Engineering, Faculty of Engineering, Erciyes University, Kayseri (Turkey)

    2008-09-15

    In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples (p<0.05). S. aureus counts were decreased to 4 log cfu/g after being exposed to irradiation at a dose of 1 kGy. Although it was ineffective on elimination of S. typhimurium, irradiation at a dose of 3.2 kGy reduced E. coli O157:H7 and S. aureus counts under detectable values in the meatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses.

  13. Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

    International Nuclear Information System (INIS)

    Gumus, Tuncay; Sukru Demirci, A.; Murat Velioglu, H.; Velioglu, Serap D.; Yilmaz, Ismail; Sagdic, Osman

    2008-01-01

    In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples (p<0.05). S. aureus counts were decreased to 4 log cfu/g after being exposed to irradiation at a dose of 1 kGy. Although it was ineffective on elimination of S. typhimurium, irradiation at a dose of 3.2 kGy reduced E. coli O157:H7 and S. aureus counts under detectable values in the meatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses

  14. Intrauterine inoculation of minipigs with Chlamydia trachomatis during diestrus establishes a longer lasting infection compared to vaginal inoculation during estrus.

    Science.gov (United States)

    Lorenzen, Emma; Follmann, Frank; Secher, Jan O; Goericke-Pesch, Sandra; Hansen, Mette S; Zakariassen, Hannah; Olsen, Anja W; Andersen, Peter; Jungersen, Gregers; Agerholm, Jørgen S

    2017-06-01

    Advanced animal models, such as minipigs, are needed for the development of a globally requested human Chlamydia vaccine. Previous studies have shown that vaginal inoculation of sexually mature Göttingen minipigs with Chlamydia trachomatis resulted in an infection lasting only 3-5 days. The aim of this study was to evaluate the effect of targeting the upper porcine genital tract by transcervical and transabdominal intrauterine inoculation, compared to previously performed vaginal inoculation. Furthermore, we investigated the effect of the hormonal cycle, estrus vs. diestrus, on the establishment of a C. trachomatis infection in the minipig. Targeting the upper genital tract (transcervical inoculation) resulted in a longer lasting infection (at least 7 days) compared to vaginal inoculation (3-5 days). When comparing intrauterine inoculation during estrus and diestrus, inoculation during diestrus resulted in a longer lasting infection (at least 10 days) compared to estrus (3-5 days). Furthermore, we found a significant C. trachomatis specific IFN-γ response in pigs inoculated during estrus correlating with the accelerated clearance of infection in these pigs. These findings suggest that for implementation of an optimal model of C. trachomatis in minipigs, inoculation should bypass the cervix and preferable be performed during diestrus. Copyright © 2017 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.

  15. Effect of food microstructure on growth dynamics of Listeria monocytogenes in fish-based model systems.

    Science.gov (United States)

    Verheyen, Davy; Bolívar, Araceli; Pérez-Rodríguez, Fernando; Baka, Maria; Skåra, Torstein; Van Impe, Jan F

    2018-06-01

    Traditionally, predictive growth models for food pathogens are developed based on experiments in broth media, resulting in models which do not incorporate the influence of food microstructure. The use of model systems with various microstructures is a promising concept to get more insight into the influence of food microstructure on microbial dynamics. By means of minimal variation of compositional and physicochemical factors, these model systems can be used to study the isolated effect of certain microstructural aspects on microbial growth, survival and inactivation. In this study, the isolated effect on microbial growth dynamics of Listeria monocytogenes of two food microstructural aspects and one aspect influenced by food microstructure were investigated, i.e., the nature of the food matrix, the presence of fat droplets, and microorganism growth morphology, respectively. To this extent, fish-based model systems with various microstructures were used, i.e., a liquid, a second more viscous liquid system containing xanthan gum, an emulsion, an aqueous gel, and a gelled emulsion. Growth experiments were conducted at 4 and 10 °C, both using homogeneous and surface inoculation (only for the gelled systems). Results regarding the influence of the growth morphology indicated that the lag phase of planktonic cells in the liquid system was similar to the lag phase of submerged colonies in the xanthan system. The lag phase of submerged colonies in each gelled system was considerably longer than the lag phase of surface colonies on these respective systems. The maximum specific growth rate of planktonic cells in the liquid system was significantly lower than for submerged colonies in the xanthan system at 10 °C, while no significant differences were observed at 4 °C. The maximum cell density was higher for submerged colonies than for surface colonies. The nature of the food matrix only exerted an influence on the maximum specific growth rate, which was

  16. Phosphatidylinositol 4,5-Bisphosphate (PtdIns(4,5)P2) Specifically Induces Membrane Penetration and Deformation by Bin/Amphiphysin/Rvs (BAR) Domains*

    Science.gov (United States)

    Yoon, Youngdae; Zhang, Xiuqi; Cho, Wonhwa

    2012-01-01

    Cellular proteins containing Bin/amphiphysin/Rvs (BAR) domains play a key role in clathrin-mediated endocytosis. Despite extensive structural and functional studies of BAR domains, it is still unknown how exactly these domains interact with the plasma membrane containing phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and whether they function by a universal mechanism or by different mechanisms. Here we report that PtdIns(4,5)P2 specifically induces partial membrane penetration of the N-terminal amphiphilic α-helix (H0) of two representative N-BAR domains from Drosophila amphiphysin (dAmp-BAR) and rat endophilin A1 (EndoA1-BAR). Our quantitative fluorescence imaging analysis shows that PtdIns(4,5)P2-dependent membrane penetration of H0 is important for self-association of membrane-bound dAmp-BAR and EndoA1-BAR and their membrane deformation activity. EndoA1-BAR behaves differently from dAmp-BAR because the former has an additional amphiphilic α-helix that penetrates the membrane in a PtdIns(4,5)P2-independent manner. Depletion of PtdIns(4,5)P2 from the plasma membrane of HEK293 cells abrogated the membrane deforming activity of EndoA1-BAR and dAmp-BAR. Collectively, these studies suggest that the local PtdIns(4,5)P2 concentration in the plasma membrane may regulate the membrane interaction and deformation by N-BAR domain-containing proteins during clathrin-mediated endocytosis. PMID:22888025

  17. Genotyping of Listeria monocytogenes isolates from poultry carcasses using high resolution melting (HRM) analysis.

    Science.gov (United States)

    Sakaridis, Ioannis; Ganopoulos, Ioannis; Madesis, Panagiotis; Tsaftaris, Athanasios; Argiriou, Anagnostis

    2014-01-02

    An outbreak situation of human listeriosis requires a fast and accurate protocol for typing Listeria monocytogenes . Existing techniques are either characterized by low discriminatory power or are laborious and require several days to give a final result. Polymerase chain reaction (PCR) coupled with high resolution melting (HRM) analysis was investigated in this study as an alternative tool for a rapid and precise genotyping of L. monocytogenes isolates. Fifty-five isolates of L. monocytogenes isolated from poultry carcasses and the environment of four slaughterhouses were typed by HRM analysis using two specific markers, internalin B and ssrA genes. The analysis of genotype confidence percentage of L. monocytogenes isolates produced by HRM analysis generated dendrograms with two major groups and several subgroups. Furthermore, the analysis of the HRM curves revealed that all L. monocytogenes isolates could easily be distinguished. In conclusion, HRM was proven to be a fast and powerful tool for genotyping isolates of L. monocytogenes .

  18. Restraining reactive oxygen species in Listeria monocytogenes promotes the apoptosis of glial cells.

    Science.gov (United States)

    Li, Sen; Li, Yixuan; Chen, Guowei; Zhang, Jingchen; Xu, Fei; Wu, Man

    2017-07-01

    Listeria monocytogenes is a facultative anaerobic foodborne pathogen that can traverse the blood-brain barrier and cause brain infection. L. monocytogenes infection induces host cell apoptosis in several cell types. In this study, we investigated the apoptosis of human glioma cell line U251 invaded by L. monocytogenes and evaluated the function of bacterial reactive oxygen species (ROS) during infection. Bacterial ROS level was reduced by carrying out treatment with N-acetyl cysteine (NAC) and diphenyleneiodonium chloride (DPI). After infection, the apoptosis of U251 cells was examined by flow cytometry assay and propidium iodide staining. DPI and NAC efficiently decreased ROS level in L. monocytogenes without affecting bacterial growth. Moreover, the apoptosis of glial cells was enhanced upon invasion of DPI- and NAC-pretreated L. monocytogenes. Results indicate that the apoptosis of glial cells can be induced by L. monocytogenes, and that the inhibition of bacterial ROS increases the apoptosis of host cells.

  19. Listeria monocytogenes serovar 4a is a possible evolutionary intermediate between L. monocytogenes serovars 1/2a and 4b and L. innocua.

    Science.gov (United States)

    Chen, Jianshun; Jiang, Lingli; Chen, Xueyan; Luo, Xiaokai; Chen, Yang; Yu, Ying; Tian, Guoming; Liu, Dongyou; Fang, Weihuan

    2009-03-01

    The genus Listeria consists of six closely related species and forms three phylogenetic groups: L. monocytogenes- L. innocua, L. ivanovii-L. seeligeri-L. welshimeri, and L. grayi. In this report, we attempted to examine the evolutionary relationship in the L. monocytogenes-L. innocua group by probing the nucleotide sequences of 23S rRNA and 16S rRNA, and the gene clusters lmo0029-lmo0042, ascBdapE, rplS-infC, and prs-ldh in L. monocytogenes serovars 1/2a, 4a, and 4b, and L. innocua. Additionally, we assessed the status of L. monocytogenes-specific inlA and inlB genes and 10 L. innocua-specific genes in these species/serovars, together with phenotypic characterization by using in vivo and in vitro procedures. The results indicate that L. monocytogenes serovar 4a strains are genetically similar to L. innocua in the lmo0035-lmo0042, ascB-dapE, and rplS-infC regions and also possess L. innocua-specific genes lin0372 and lin1073. Furthermore, both L. monocytogenes serovar 4a and L. innocua exhibit impaired intercellular spread ability and negligible pathogenicity in mouse model. On the other hand, despite resembling L. monocytogenes serovars 1/2a and 4b in having a nearly identical virulence gene cluster, and inlA and inlB genes, these serovar 4a strains differ from serovars 1/2a and 4b by harboring notably altered actA and plcB genes, displaying strong phospholipase activity and subdued in vivo and in vitro virulence. Thus, by possessing many genes common to L. monocytogenes serovars 1/2a and 4b, and sharing many similar gene deletions with L. innocua, L. monocytogenes serovar 4a represents a possible evolutionary intermediate between L. monocytogenes serovars 1/2a and 4b and L. innocua.

  20. effect of tillage, rhizobium inoculation in maize-soybean- based ...

    African Journals Online (AJOL)

    main plot, four rhizobium inoculation in soybean-maize-based cropping systems ... production systems, such as cropping systems, ... of commercial inoculants. Studies ... and distributed by IITA business incubation ... sowing, while the remaining part (2/3) was done as ...... biological nitrogen fixation potential and grain yield.

  1. Effects of single and combined inoculations of selected Trichoderma ...

    African Journals Online (AJOL)

    Effects of single and combined inoculations of selected Trichoderma and Bacillus isolates on growth of dry bean and biological control of Rhizoctonia solani damping-off. ... Greenhouse trials showed that combined inoculations of T. atroviride strain 6 and B. subtilis B69 gave the highest growth promotion of bean in terms of ...

  2. Lactating cow response to lucerne silage inoculated with Lactobacillus plantarum

    Science.gov (United States)

    It is unclear why bacterial silage inoculants improve milk production in lactating dairy cattle. However, recent in vitro results suggest that inoculated silage effects on milk production may be tied to greater production of rumen microorganisms. Our objective was to determine if alfalfa silage trea...

  3. Response of chickpea ( Cicer arietinum L.) to inoculation with native ...

    African Journals Online (AJOL)

    The results from the field and pot experiments indicated that chickpea crop yield can be improved using proper Mesorhizobium inoculation. Inoculation had a pronounced effect on grain yield, yield component, total N uptake, grain protein content, percentage N derived from the atmosphere (%Ndfa) for the seed, and amount ...

  4. smallholder farmers' use and profitability of legume inoculants

    African Journals Online (AJOL)

    ACSS

    Rhizobia inoculant, a product of Kenya, and its profitability in smallholder farms. Data were collected from ... of the inoculants use and gross margin analysis to examine profitability. The area under the .... the effects of various factors on the extent of. BIOFIX® use. ..... little information, resulting in reduced adoption of legume ...

  5. Synthesis and characterization of copolymers 4,5-dihydroisoxazole and (-)-menthyl acrylates

    International Nuclear Information System (INIS)

    Passo, Joel A.; Merlo, Aloir A.; Eccher, Juliana; Bechtold, Ivan H.; Kelly, Stephen M.

    2012-01-01

    Five monomers 5-[4-(5-cyano-4,5-dihydroisoxazol-3-yl)phenoxy]undecyl acrylate (7a); n-alkyl 3-{4-[5-(acryloyloxyundecyl)oxyphenyl]}-4,5-dihydroisoxazole-5-carboxylate (7b,c for n-butyl and n-hexyl, respectively); 3-{4-[5-(acryloyloxyundecyl) oxyphenyl]}-4,5-dihydroisoxazole-5-carboxylic acid (7d) and (1R,2S,5R)-2-isopropyl-5-methylcyclohexyl acrylate (9) and the corresponding copolymers 10a-d,11 and homopolymers 12 from 7a and 13 from 9 were designed and synthesized. Except for acrylate 9 which is derived from (-)-menthol, all of the monomers belong to the series containing the isoxazoline ring linked to the acrylate unit by a flexible spacer chain of eleven methylene units. They presented low glass temperature and despite birefringence behavior, these copolymers showed no mesomorphic properties. (author)

  6. L. monocytogenes in a cheese processing facility: Learning from contamination scenarios over three years of sampling.

    Science.gov (United States)

    Rückerl, I; Muhterem-Uyar, M; Muri-Klinger, S; Wagner, K-H; Wagner, M; Stessl, B

    2014-10-17

    The aim of this study was to analyze the changing patterns of Listeria monocytogenes contamination in a cheese processing facility manufacturing a wide range of ready-to-eat products. Characterization of L. monocytogenes isolates included genotyping by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Disinfectant-susceptibility tests and the assessment of L. monocytogenes survival in fresh cheese were also conducted. During the sampling period between 2010 and 2013, a total of 1284 environmental samples were investigated. Overall occurrence rates of Listeria spp. and L. monocytogenes were 21.9% and 19.5%, respectively. Identical L. monocytogenes genotypes were found in the food processing environment (FPE), raw materials and in products. Interventions after the sampling events changed contamination scenarios substantially. The high diversity of globally, widely distributed L. monocytogenes genotypes was reduced by identifying the major sources of contamination. Although susceptible to a broad range of disinfectants and cleaners, one dominant L. monocytogenes sequence type (ST) 5 could not be eradicated from drains and floors. Significantly, intense humidity and steam could be observed in all rooms and water residues were visible on floors due to increased cleaning strategies. This could explain the high L. monocytogenes contamination of the FPE (drains, shoes and floors) throughout the study (15.8%). The outcome of a challenge experiment in fresh cheese showed that L. monocytogenes could survive after 14days of storage at insufficient cooling temperatures (8 and 16°C). All efforts to reduce L. monocytogenes environmental contamination eventually led to a transition from dynamic to stable contamination scenarios. Consequently, implementation of systematic environmental monitoring via in-house systems should either aim for total avoidance of FPE colonization, or emphasize a first reduction of L. monocytogenes to sites where

  7. Recombinant probiotic expressing Listeria adhesion protein attenuates Listeria monocytogenes virulence in vitro.

    Directory of Open Access Journals (Sweden)

    Ok Kyung Koo

    Full Text Available BACKGROUND: Listeria monocytogenes, an intracellular foodborne pathogen, infects immunocompromised hosts. The primary route of transmission is through contaminated food. In the gastrointestinal tract, it traverses the epithelial barrier through intracellular or paracellular routes. Strategies to prevent L. monocytogenes entry can potentially minimize infection in high-risk populations. Listeria adhesion protein (LAP aids L. monocytogenes in crossing epithelial barriers via the paracellular route. The use of recombinant probiotic bacteria expressing LAP would aid targeted clearance of Listeria from the gut and protect high-risk populations from infection. METHODOLOGY/PRINCIPAL FINDINGS: The objective was to investigate the ability of probiotic bacteria or LAP-expressing recombinant probiotic Lactobacillus paracasei (Lbp(LAP to prevent L. monocytogenes adhesion, invasion, and transwell-based transepithelial translocation in a Caco-2 cell culture model. Several wild type probiotic bacteria showed strong adhesion to Caco-2 cells but none effectively prevented L. monocytogenes infection. Pre-exposure to Lbp(LAP for 1, 4, 15, or 24 h significantly (P<0.05 reduced adhesion, invasion, and transepithelial translocation of L. monocytogenes in Caco-2 cells, whereas pre-exposure to parental Lb. paracasei had no significant effect. Similarly, Lbp(LAP pre-exposure reduced L. monocytogenes translocation by as much as 46% after 24 h. Lbp(LAP also prevented L. monocytogenes-mediated cell damage and compromise of tight junction integrity. Furthermore, Lbp(LAP cells reduced L. monocytogenes-mediated cell cytotoxicity by 99.8% after 1 h and 79% after 24 h. CONCLUSIONS/SIGNIFICANCE: Wild type probiotic bacteria were unable to prevent L. monocytogenes infection in vitro. In contrast, Lbp(LAP blocked adhesion, invasion, and translocation of L. monocytogenes by interacting with host cell receptor Hsp60, thereby protecting cells from infection. These data show promise

  8. Internalization of Listeria monocytogenes in cantaloupes during dump tank washing and hydrocooling.

    Science.gov (United States)

    Macarisin, Dumitru; Wooten, Anna; De Jesus, Antonio; Hur, Minji; Bae, Seonjae; Patel, Jitendra; Evans, Peter; Brown, Eric; Hammack, Thomas; Chen, Yi

    2017-09-18

    Recent listeriosis outbreaks and recalls associated with cantaloupes urge for studies to understand the mechanisms of cantaloupe contamination by Listeria monocytogenes. Postharvest practices such as washing and hydrocooling were suggested to facilitate the contamination of fresh fruits by human pathogens. This study assessed the potential of L. monocytogenes internalization into cantaloupes during dump tank washing and immersion-type hydrocooling in water contaminated with L. monocytogenes. The effect of cantaloupe cultivar, water temperature, and harvesting technique on L. monocytogenes internalization was also evaluated. Full slip (cantaloupe without any residual stem) Western and Eastern cultivar cantaloupes were pre-warmed to 42°C (to imitate peak-high field temperatures of freshly harvested cantaloupes) and then immersed in water at 6°C and 18°C containing 4 and 6logCFU/ml of L. monocytogenes. Clipped (cantaloupe with short stem residues obtained by clipping the stem at harvest) Western and Eastern cantaloupes were pre-warmed to 42°C and then immersed in water at 6°C containing 6logCFU/ml of L. monocytogenes. Additionally, full slip and clipped Western cantaloupes were equilibrated to 18°C and then immersed in water at 18°C containing 6logCFU/ml of L. monocytogenes (isothermal immersion without temperature differential). Water containing L. monocytogenes infiltrated both full slip and clipped cantaloupes through the stems/stem scars and was then distributed along the vascular system in hypodermal mesocarp reaching the calyx area of the fruit. The current study demonstrated that, under experimental conditions, L. monocytogenes can internalize into cantaloupes during immersion in water contaminated by L. monocytogenes, both in the presence and absence of temperature differential, and that temperature differential moderately enhanced the internalization of L. monocytogenes. The incidence and levels of L. monocytogenes internalized in the middle

  9. Specific receptor for inositol-1,4,5-trisphosphate in permeabilized rabbit neutrophils

    International Nuclear Information System (INIS)

    Bradford, P.G.; Spat, A.; Rubin, R.P.

    1986-01-01

    Neutrophil chemotaxis and degranulation are resultant, in part, from the mobilization of intracellular calcium by inositol-1,4,5-trisphosphate [(1,4,5)IP 3 ], one of the products of chemoattractant-stimulated phospholipase C activity. High specific activity (ca. 40 Ci/mmol) [ 32 P](1,4,5)IP 3 was prepared from [γ- 32 P]ATP-labeled human erythrocyte ghosts and was used in binding assays with saponin-permeabilized rabbit peritoneal neutrophils. At 4 0 C and in the presence of inhibitors of the IP 3 5-phosphomonoesterase, [ 32 P](1,4,5)IP 3 rapidly associated with a specific binding component which saturated within 60s. Nonspecific binding, taken as the residual binding in the presence of 10 μM (1,4,5)IP 3 , was 15% of the total. No specific binding was detected using intact cells. The specific binding to permeable cells was reversible (t/sup 1/2/ ∼ 60s) and could be inhibited in a dose-dependent manner by (1,4,5)IP 3 (EC 50 = 30 nM) and by other calcium mobilizing inositol phosphates [(2,4,5)IP 3 ] but not by inactive analogs [(1,4)IP 2 , (4,5)IP 2 , (1)IP]. The dose-responses of (1,4,5)IP 3 and (2,4,5)IP 3 in inhibiting [ 32 P](1,4,5)IP 3 specific binding correlated well with their abilities to release Ca 2+ from nonmitochondrial vesicular stores in the same preparation of cells, suggesting that the authors have identified the physiological receptor for (1,4,5)IP 3

  10. Lineage specific recombination rates and microevolution in Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Nightingale Kendra K

    2008-10-01

    Full Text Available Abstract Background The bacterium Listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages I and II and an uncommon lineage (lineage III. While some L. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to L. monocytogenes evolution is still limited. We therefore used STRUCTURE and ClonalFrame, two programs that model the effect of recombination, to make inferences about the population structure and different aspects of the recombination process in L. monocytogenes. Analyses were performed using sequences for seven loci (including the house-keeping genes gap, prs, purM and ribC, the stress response gene sigB, and the virulence genes actA and inlA for 195 L. monocytogenes isolates. Results Sequence analyses with ClonalFrame and the Sawyer's test showed that recombination is more prevalent in lineage II than lineage I and is most frequent in two house-keeping genes (ribC and purM and the two virulence genes (actA and inlA. The relative occurrence of recombination versus point mutation is about six times higher in lineage II than in lineage I, which causes a higher genetic variability in lineage II. Unlike lineage I, lineage II represents a genetically heterogeneous population with a relatively high proportion (30% average of genetic material imported from external sources. Phylograms, constructed with correcting for recombination, as well as Tajima's D data suggest that both lineages I and II have suffered a population bottleneck. Conclusion Our study shows that evolutionary lineages within a single bacterial species can differ considerably in the relative contributions of recombination to genetic diversification. Accounting for recombination in phylogenetic studies is critical, and new evolutionary models that

  11. Determination of inositol 1,4,5-trisphosphate levels in Dictyostelium by isotope dilution assay

    International Nuclear Information System (INIS)

    Van Haastert, P.J.

    1989-01-01

    A commercial isotope dilution assay was used for the determination of Ins(1,4,5)P3 levels in the microorganism Dictyostelium discoideum. Cross-reactivity in the assay was detected with extracts from cells and the medium. The compound which induced this cross-reactivity was tentatively identified as Ins(1,4,5)P3 by (i) codegradation with authentic [ 32 P]Ins(1,4,5)P3 by three specific Ins(1,4,5)P3 phosphatases, and (ii) co-chromatography with authentic [ 32 P]Ins(1,4,5)P3 on HPLC columns. The cellular concentration was estimated as 165 +/- 42 pmol/10(8) cells, yielding a mean intracellular Ins(1,4,5)P3 concentration of 3.3 microM. Dictyostelium cells secrete large amounts of Ins(1,4,5)P3 at a rate of about 10% of the cellular content per minute, yielding about 0.13 microM extracellular Ins(1,4,5)P3 after 15 min in a suspension of 10(8) cells/ml. The chemoattractant cAMP induced a transient increase of the Ins(1,4,5)P3 concentration; the data suggest an intracacellular rise from 3.3 to 5.5 microM with a maximum at 6 s after stimulation

  12. Xenon spectator and diagram L3-M4,5M4,5 Auger intensities near the L3 threshold

    International Nuclear Information System (INIS)

    Armen, G.B.; Levin, J.C.; Southworth, S.H.; LeBrun, T.; Arp, U.; MacDonald, M.A.

    1997-01-01

    Calculations based on the theory of radiationless resonant Raman scattering are employed in the interpretation of new XeL 3 -M 4,5 M 4,5 Auger spectra recorded using synchrotron radiation tuned to energies across the L 3 edge. Fits of theoretical line shapes to the spectra are employed in separating intensities due to nd spectator (resonant) and diagram Auger processes. Near-threshold Auger intensity, previously attributed to diagram decay, is found to be due to the large-n spectator lines that result from postcollision-interaction endash induced open-quotes recaptureclose quotes of threshold photoelectrons to nd orbitals. copyright 1997 The American Physical Society

  13. Antioxidant properties of soybean seedlings inoculated with Trichoderma asperellum

    Directory of Open Access Journals (Sweden)

    Manojlović Ana S.

    2017-01-01

    Full Text Available This study was conducted in order to assess the effect of inoculation of soybean (Glycine max L. seeds with Trichoderma asperellum, followed by mites (Tetranychus urticae exposure on lipid peroxidation (LP process and the activity of antioxidant enzymes. T. urticae is an occasional pest of soybean that causes biotic stress. Biotic stress leads to overproduction of reactive oxygen species (ROS which may cause damage to vital biomolecules. Enzymatic antioxidant defense systems protect plants against oxidative stress. T. asperellum is commonly used as biocontrol agent against plant pathogens. It has been suggested that previous inoculation of seeds with T. asperellum may cause induced resistance against biotic stress. The aim of this study was to determine LP intensity and antioxidant enzymes activity in inoculated and non-inoculated soybean seedlings with and without exposure to mites. Noticeably higher LP intensity was detected in non-inoculated group treated with mites compared to control group. Inoculated soybean seedlings treated with mites had lower LP intensity compared to noninoculated group. Also, it has been noticed that inoculation with Trichoderma asperellum itself, produced mild stress in plants. In addition, positive correlation between enzymes activity and LP was noticed. The level of oxidative stress in plants was followed by the change of LP intensity. According to results obtained, it was concluded that the greatest oxidative stress occurred in non-inoculated group treated with mites and that inoculation successfully reduced oxidative stress. The results indicate that inoculation of soybean seeds with T. asperellum improves resistance of soybean seedlings against mites attack. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31022

  14. Presence of Listeria monocytogenes in Mediterranean-Style Dry Fermented Sausages

    Directory of Open Access Journals (Sweden)

    Domenico Meloni

    2015-03-01

    Full Text Available The morphological, physiological and epidemiological features of L. monocytogenes, together with the severity of human listeriosis infections, make L. monocytogenes of particular concern for manufacturers of cold-stored “ready to eat” (RTE foods. L. monocytogenes has been isolated from a wide variety of RTE foods and is responsible for several outbreaks associated with the consumption of RTE meat, poultry, dairy, fish and vegetable products. Although L. monocytogenes is among the most frequently-detected pathogens in dry fermented sausages, these products could be included in the category of RTE products in which the growth of L. monocytogenes is not favored and have rarely been implicated in listeriosis outbreaks. However, L. monocytogenes is highly difficult to control in fermented sausage processing environments due to its high tolerance to low pH and high salt concentration. In many Mediterranean-style dry fermented sausages, an empirical application of the hurdle technology often occurs and the frequent detection of L. monocytogenes in these products at the end of ripening highlights the need for food business operators to properly apply hurdle technology and to control the contamination routes of L. monocytogenes in the processing plants. In the following, through an up-to-date review of (personal and un- published data, the main aspects of the presence of L. monocytogenes in Mediterranean-style dry fermented sausages will be discussed.

  15. Presence of Listeria monocytogenes in Mediterranean-Style Dry Fermented Sausages.

    Science.gov (United States)

    Meloni, Domenico

    2015-03-12

    The morphological, physiological and epidemiological features of L. monocytogenes , together with the severity of human listeriosis infections, make L. monocytogenes of particular concern for manufacturers of cold-stored "ready to eat" (RTE) foods. L. monocytogenes has been isolated from a wide variety of RTE foods and is responsible for several outbreaks associated with the consumption of RTE meat, poultry, dairy, fish and vegetable products. Although L. monocytogenes is among the most frequently-detected pathogens in dry fermented sausages, these products could be included in the category of RTE products in which the growth of L. monocytogenes is not favored and have rarely been implicated in listeriosis outbreaks. However, L. monocytogenes is highly difficult to control in fermented sausage processing environments due to its high tolerance to low pH and high salt concentration. In many Mediterranean-style dry fermented sausages, an empirical application of the hurdle technology often occurs and the frequent detection of L. monocytogenes in these products at the end of ripening highlights the need for food business operators to properly apply hurdle technology and to control the contamination routes of L. monocytogenes in the processing plants. In the following, through an up-to-date review of (personal and un-) published data, the main aspects of the presence of L. monocytogenes in Mediterranean-style dry fermented sausages will be discussed.

  16. Effects of essential oils of oregano and nutmeg on growth and survival of Yersinia enterocolitica and Listeria monocytogenes in barbecued chicken.

    Science.gov (United States)

    Firouzi, R; Shekarforoush, S S; Nazer, A H K; Borumand, Z; Jooyandeh, A R

    2007-11-01

    The in vitro effects of plant essential oils (EOs) against pathogenic bacteria are well known, yet few studies have addressed the effects of these compounds against pathogens associated with ready-to-cook foods. Experiments were conducted to determine the effectiveness of oregano and nutmeg EOs on the growth and survival of Yersinia enterocolitica and Listeria monocytogenes in broth culture and in Iranian barbecued chicken. Ready-to-cook Iranian barbecued chicken was prepared according to the common practice with 1, 2, and 3 microl/g of oregano and nutmeg EOs. The test and control (without EOs) samples were inoculated with Y. enterocolitica and L. monocytogenes to a final concentration of 6 to 7 log CFU/g and stored at 3, 8, and 20 degrees C. Microorganisms were counted just before and at 24, 48, and 72 h after storage based on growth on Yersinia selective agar supplemented with cefsulodine, igrasan, and novobiocin and on Listeria selective agar supplemented with nalidixic acid and acriflavin. In the broth culture system, the nutmeg EO had a greater effect on L. monocytogenes (MIC = 0.20 nicrol/ml) than did the oregano EO (MIC = 0.26 microl/ml). However, the oregano EO had a greater effect on Y. enterocolitica (MIC = 0.16 microl/ml) than did the nutmeg EO (MIC = 0.25 microl/ml). In ready-to-cook Iranian barbecued chicken, the log CFU per gram of both bacteria after up to 72 h of incubation was not decreased significantly by various combinations of oregano and nutmeg EOs (1, 2, and 3 microl/g) and storage temperatures (3, 8, and 20 degrees C) when compared with control samples (without EOs). Although examination of spices in culture media can yield accurate microbiological data, without complementary tests in foods these data are of limited value for assessing food safety.

  17. Inactivation of Escherichia coli, Listeria monocytogenes, and Salmonella Enteritidis by Cymbopogon citratus D.C. Stapf. Essential Oil in Pineapple Juice.

    Science.gov (United States)

    Leite, Caroline Junqueira Barcellos; de Sousa, Jossana Pereira; Medeiros, José Alberto da Costa; da Conceição, Maria Lúcia; dos Santos Falcão-Silva, Vivyanne; de Souza, Evandro Leite

    2016-02-01

    In the present study, the efficacy of Cymbopogon citratus D.C. Stapf. essential oil (CCEO) to provoke a 5-log CFU/ml (5-log) inactivation in a mixed composite of Escherichia coli, Listeria monocytogenes, and Salmonella enterica serovar Enteritidis in pineapple (Ananas comosus (L.) Merril) juice (4°C) was assessed. Moreover, the effects of CCEO on the physicochemical and sensory quality parameters of pineapple juice were evaluated. The MIC of CCEO was 5 μl/ml against the composite mix examined. For L. monocytogenes and E. coli inoculated in juice containing CCEO (5, 2.5, and 1.25 μl/ml), a ≥5-log reduction was detected after 15 min of exposure. This same result was obtained for Salmonella Enteritidis incubated alone in pineapple juice containing CCEO at 5 and 2.5 μl/ml. Overall, Salmonella Enteritidis was the most tolerant and L. monocytogenes was the most sensitive to CCEO. The physicochemical properties (pH, titratable acidic [citric acid per 100 g], and soluble solids) of pineapple juice containing CCEO (2.5 and 1.25 μl/ml) were maintained. Juice containing CCEO (2.5 and 1.25 μl/ml) exhibited similar scores for odor, appearance, and viscosity compared with juice without CCEO. However, unsatisfactory changes in taste and aftertaste were observed in juices containing CCEO. These results suggest that CCEO could be used as an alternative antimicrobial compound to ensure the safety of pineapple juice, although CCEO at the tested concentrations negatively impacted its taste. Therefore, further studies are needed to determine the balance between microbial safety and taste acceptability of pineapple juice containing CCEO.

  18. Uncovering Listeria monocytogenes hypervirulence by harnessing its biodiversity

    Science.gov (United States)

    Charlier, Caroline; Touchon, Marie; Chenal-Francisque, Viviane; Leclercq, Alexandre; Criscuolo, Alexis; Gaultier, Charlotte; Roussel, Sophie; Brisabois, Anne; Disson, Olivier; Rocha, Eduardo P. C.; Brisse, Sylvain; Lecuit, Marc

    2016-01-01

    Microbial pathogenesis studies are typically performed with reference strains, thereby overlooking microbial intra-species virulence heterogeneity. Here we integrated human epidemiological and clinical data with bacterial population genomics to harness the biodiversity of the model foodborne pathogen Listeria monocytogenes and decipher the basis of its neural and placental tropisms. Taking advantage of the clonal structure of this bacterial species, we identify clones epidemiologically associated with either food or human central nervous system (CNS) and maternal-neonatal (MN) listeriosis. The latter are also most prevalent in patients without immunosuppressive comorbidities. Strikingly, CNS and MN clones are hypervirulent in a humanized mouse model of listeriosis. By integrating epidemiological data and comparative genomics, we uncovered multiple novel putative virulence factors and demonstrated experimentally the contribution of the first gene cluster mediating Listeria monocytogenes neural and placental tropisms. This study illustrates the exceptional power of harnessing microbial biodiversity to identify clinically relevant microbial virulence attributes. PMID:26829754

  19. Biosensor for the detection of Listeria monocytogenes: emerging trends

    KAUST Repository

    Soni, Dharmendra Kumar

    2018-05-23

    The early detection of Listeria monocytogenes (L. monocytogenes) and understanding the disease burden is of paramount interest. The failure to detect pathogenic bacteria in the food industry may have terrible consequences, and poses deleterious effects on human health. Therefore, integration of methods to detect and trace the route of pathogens along the entire food supply network might facilitate elucidation of the main contamination sources. Recent research interest has been oriented towards the development of rapid and affordable pathogen detection tools/techniques. An innovative and new approach like biosensors has been quite promising in revealing the foodborne pathogens. In spite of the existing knowledge, advanced research is still needed to substantiate the expeditious nature and sensitivity of biosensors for rapid and in situ analysis of foodborne pathogens. This review summarizes recent developments in optical, piezoelectric, cell-based, and electrochemical biosensors for Listeria sp. detection in clinical diagnostics, food analysis, and environmental monitoring, and also lists their drawbacks and advantages.

  20. Teriyaki sauce with carvacrol or thymol effectively controls Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and indigenous flora in marinated beef and marinade.

    Science.gov (United States)

    Moon, Hyeree; Kim, Nam Hee; Kim, Soon Han; Kim, Younghoon; Ryu, Jee Hoon; Rhee, Min Suk

    2017-07-01

    An effective bactericidal cold-marinating method for beef products is described, exploiting the synergism between soy sauce and natural compounds (carvacrol, CV or thymol, TM) to reduce microbiological risks. Beef slices inoculated with Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium (3.1-3.5logCFU/g) were marinated in a teriyaki sauce with or without CV and TM (0.3 and 0.5%). After 1, 3, and 7days at 4°C, indigenous microflora population, color, lipid oxidation, marinade uptake, and pH of marinated beef and leftover marinade samples were examined. Teriyaki sauce alone did not reduce or inhibit any of the target pathogens or indigenous bacteria, while 0.5% CV- or TM-containing teriyaki sauce inactivated all inocula without recovery within 7days (p0.05). Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Survival of Listeria monocytogenes, Yersinia enterocolitica and Escherichia coli O157:H7 and quality changes after irradiation of beef steaks and ground beef

    International Nuclear Information System (INIS)

    Fu, A.H.; Sebranek, J.G.; Murano, E.A.

    1995-01-01

    Beef steaks and ground beef were inoculated with Listeria monocytogenes, Yersinia enterocolitica, or Escherichia coli O157:H7. Samples were packaged in air or under vacuum and irradiated at low (0.60 to 0.80 kGy) or medium (1.5 to 2.0 kGy) doses, with each dose delivered at either a low (2.8 M/min conveyor speed) or high (6.9 M/min) dose rate. Medium-dose irradiation accompanied by 7 degrees C storage resulted in no Y. enterocolitica or E. coli O157:H7 survivors being detected. There was no effect on survival of the pathogens by dose rate or storage atmosphere. No difference (P0.05) was observed in meat pH or color, but TBA values increased after 7 days storage

  2. Unprecedentedly mild direct Pd-catalyzed arylation of oxazolo[4,5-b]pyridine

    DEFF Research Database (Denmark)

    Zhuravlev, Fedor

    2006-01-01

    Pd-catalyzed C-2 arylation of oxazolo[4,5-b]pyridine proceeds efficiently at 30 degrees C and tolerates a variety of aryl halides, including derivatized amino acids for which no racemization was observed during the reaction. Experimental evidence for facile deprotonation of oxazolo[4,5-b...

  3. 39 CFR 4.5 - Assistant Postmasters General, General Counsel, Judicial Officer, Chief Postal Inspector.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Assistant Postmasters General, General Counsel, Judicial Officer, Chief Postal Inspector. 4.5 Section 4.5 Postal Service UNITED STATES POSTAL SERVICE THE... Counsel, a Judicial Officer, a Chief Postal Inspector, and such number of officers, described in 39 U.S.C...

  4. Genetic selection and DNA sequences of 4.5S RNA homologs

    DEFF Research Database (Denmark)

    Brown, S; Thon, G; Tolentino, E

    1989-01-01

    A general strategy for cloning the functional homologs of an Escherichia coli gene was used to clone homologs of 4.5S RNA from other bacteria. The genes encoding these homologs were selected by their ability to complement a deletion of the gene for 4.5S RNA. DNA sequences of the regions encoding...

  5. Mechanistic studies of the agmatine deiminase from Listeria monocytogenes.

    Science.gov (United States)

    Soares, Charles A; Knuckley, Bryan

    2016-06-01

    Listeria monocytogenes is a Gram-positive food-borne pathogen that is capable of living within extreme environments (i.e. low temperatures and pH). This ability to survive in such conditions may arise, at least in part, from agmatine catabolism via the agmatine deiminase system (AgDS). This catabolic pathway utilizes an agmatine deiminase (AgD) to hydrolyse agmatine into N-carbamoylputrescine (NCP), with concomitant release of ammonia, which increases the pH, thus mitigating the ill effects of the acidic environment. Given the potential significance of this pathway for cell survival, we set out to study the catalytic mechanism of the AgD encoded by L. monocytogenes In the present paper, we describe the catalytic mechanism employed by this enzyme based on pH profiles, pKa measurements of the active site cysteine and solvent isotope effects (SIE). In addition, we report inhibition of this enzyme by two novel AgD inhibitors, i.e. N-(4-aminobutyl)-2-fluoro-ethanimidamide (ABFA) and N-(4-aminobutyl)-2-chloro-ethanimidamide (ABCA). In contrast with other orthologues, L. monocytogenes AgD does not use the reverse protonation or substrate-assisted mechanism, which requires an active site cysteine with a high pKa and has been commonly seen in other members of the guanidinium-modifying enzyme (GME) superfamily. Instead, the L. monocytogenes AgD has a low pKa cysteine in the active site leading to an alternative mechanism of catalysis. This is the first time that this mechanism has been observed in the GME superfamily and is significant because it explains why previously developed mechanism-based inactivators of AgDs are ineffective against this orthologue. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  6. Encefalitis del tallo cerebral y mielitis por Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Aracelly Castro

    2013-09-01

    Full Text Available La romboencefalitis por Listeria monocytogenes es una presentación poco común de la listeriosis del sistema nervioso central; sin embargo, es la presentación más común en personas inmunocompetentes. Aun más rara es la combinación de romboencefalitis con mielitis causada por L. monocytogenes; no obstante, en este artículo se reporta un caso de encefalitis del tallo y mielitis grave en un paciente sin compromiso del sistema inmunitario. Se presenta un paciente de 21 años de edad, sin deficiencias del sistema inmunitario, que consumió productos lácteos no pasteurizados y, posteriormente, presentó un cuadro de cefalea, vómito, deterioro de su estado general y, finalmente, alteración del estado de conciencia y muerte. Consultó al Instituto Neurológico de Colombia y se hizo diagnóstico de encefalitis del tallo y mielitis por L. monocytogenes. Se discuten las diferencias entre el caso presentado y los reportados en la literatura científica. Ante un paciente con signos de compromiso del tallo cerebral, de posible origen infeccioso, es prudente iniciar tratamiento antibiótico para L. monocytogenes y, en caso de poca respuesta, escalar rápidamente en dicho tratamiento. También lo es extender el estudio radiológico hacia la columna vertebral, con el fin de descartar compromiso de la médula espinal.   doi: http://dx.doi.org/10.7705/biomedica.v33i3.1482

  7. How Listeria monocytogenes organizes its surface for virulence

    Science.gov (United States)

    Carvalho, Filipe; Sousa, Sandra; Cabanes, Didier

    2014-01-01

    Listeria monocytogenes is a Gram-positive pathogen responsible for the manifestation of human listeriosis, an opportunistic foodborne disease with an associated high mortality rate. The key to the pathogenesis of listeriosis is the capacity of this bacterium to trigger its internalization by non-phagocytic cells and to survive and even replicate within phagocytes. The arsenal of virulence proteins deployed by L. monocytogenes to successfully promote the invasion and infection of host cells has been progressively unveiled over the past decades. A large majority of them is located at the cell envelope, which provides an interface for the establishment of close interactions between these bacterial factors and their host targets. Along the multistep pathways carrying these virulence proteins from the inner side of the cytoplasmic membrane to their cell envelope destination, a multiplicity of auxiliary proteins must act on the immature polypeptides to ensure that they not only maturate into fully functional effectors but also are placed or guided to their correct position in the bacterial surface. As the major scaffold for surface proteins, the cell wall and its metabolism are critical elements in listerial virulence. Conversely, the crucial physical support and protection provided by this structure make it an ideal target for the host immune system. Therefore, mechanisms involving fine modifications of cell envelope components are activated by L. monocytogenes to render it less recognizable by the innate immunity sensors or more resistant to the activity of antimicrobial effectors. This review provides a state-of-the-art compilation of the mechanisms used by L. monocytogenes to organize its surface for virulence, with special focus on those proteins that work “behind the frontline”, either supporting virulence effectors or ensuring the survival of the bacterium within its host. PMID:24809022

  8. Mycorrhizal inoculation affects the phytochemical content in strawberry fruits

    Directory of Open Access Journals (Sweden)

    Ana Paula Cecatto

    2016-04-01

    Full Text Available The aim of this research was to evaluate the effect of the inoculation date of arbuscular mycorrhizal fungi on the fruit quality and the content of phytochemicals in a strawberry soilless growing system. The experiment was performed in Huelva (Spain and was conducted in a greenhouse on the La Rábida Campus of Huelva University under natural light and temperature from October 2013 to June 2014. Three short-day strawberry cultivars (‘Splendor’, ‘Sabrina’ and ‘Fortuna’ were grown in polyethylene bags filled with coconut fibres. Randomized block design, with 3 repetitions and factorial arrangement (3 cultivars x 3 treatments, was established. Each replicate consisted of one bag with 12 plants supporting structures at 40 cm height. The treatments were: T1 = mycorrhizal inoculation in the transplantation; T2 = mycorrhizal inoculation 30 days after transplantation (DAT; and T0 = control treatment, without inoculation. Arbuscular mycorrhizal fungi inoculation significantly affected the contents of anthocyanin and phenolics. When the inoculation is performed in the transplantation, the fruits showed a high content of anthocyanin and total phenolics. The mycorrhizal inoculation influences decreasing the acidity in fruit throughout the growing season and increase firmness only during the early stage of production.

  9. Inoculation message treatments for curbing noncommunicable disease development.

    Science.gov (United States)

    Mason, Alicia M; Miller, Claude H

    2013-07-01

    To study the effect of various types of inoculation message treatments on resistance to persuasive and potentially deceptive health- and nutrition-related (HNR) content claims of commercial food advertisers. A three-phase experiment was conducted among 145 students from a Midwestern U.S. university. Quantitative statistical analyses were used to interpret the results. RESULTS provide clear evidence that integrating regulatory focus/fit considerations enhances the treatment effectiveness of inoculation messages. Inoculation messages that employed a preventative, outcome focus with concrete language were most effective at countering HNR advertising claims. The findings indicate that inoculation fosters resistance equally across the most common types of commercially advertised HNR product claims (e.g., absolute, general, and structure/function claims). As the drive to refine the inoculation process model continues, further testing and application of this strategy in a public health context is needed to counter ongoing efforts by commercial food advertisers to avoid government regulations against deceptive practices such as dubious health/nutrition claims. This research advances inoculation theory by providing evidence that 1) good regulatory fit strengthens the effect of refutational preemption and 2) an inoculation approach is highly effective at fostering resistance to commercial advertisers' HNR content claims. This macro approach appears far superior to education or information-based promotional health campaigns targeted solely at specific populations demonstrating rising rates of noncommunicable disease.

  10. Inoculation message treatments for curbing noncommunicable disease development

    Directory of Open Access Journals (Sweden)

    Alicia M. Mason

    2013-07-01

    Full Text Available OBJECTIVE: To study the effect of various types of inoculation message treatments on resistance to persuasive and potentially deceptive health- and nutrition-related (HNR content claims of commercial food advertisers. METHODS: A three-phase experiment was conducted among 145 students from a Midwestern U.S. university. Quantitative statistical analyses were used to interpret the results. Results: Results provide clear evidence that integrating regulatory focus/fit considerations enhances the treatment effectiveness of inoculation messages. Inoculation messages that employed a preventative, outcome focus with concrete language were most effective at countering HNR advertising claims. The findings indicate that inoculation fosters resistance equally across the most common types of commercially advertised HNR product claims (e.g., absolute, general, and structure/function claims. CONCLUSIONS: As the drive to refine the inoculation process model continues, further testing and application of this strategy in a public health context is needed to counter ongoing efforts by commercial food advertisers to avoid government regulations against deceptive practices such as dubious health/nutrition claims. This research advances inoculation theory by providing evidence that 1 good regulatory fit strengthens the effect of refutational preemption and 2 an inoculation approach is highly effective at fostering resistance to commercial advertisers' HNR content claims. This macro approach appears far superior to education or information-based promotional health campaigns targeted solely at specific populations demonstrating rising rates of noncommunicable disease.

  11. Rapid anaerobic mineralization of pyridine in a subsurface sediment inoculated with a pyridine-degrading Alcaligenes sp

    Energy Technology Data Exchange (ETDEWEB)

    Ronen, Z; Bollag, J M [Pennsylvania State Univ., University Park, PA (United States). Lab. of Soil Biochemistry

    1992-05-01

    A denitrifying bacterium capable of pyridine mineralization under anaerobic conditions was isolated from polluted soil. The bacterium, identified as Alcaligenes sp., was used in inoculation experiments. A subsurface sediment from a polluted site was amended with 10 {mu}g/g {sup 14}C-labeled pyridine, and 250 {mu}g/g nitrate, and then inoculated with the bacterium at an inoculum size of 4.5x10{sup 7} cells/g. After 44 h incubation at 28deg C under anaerobic conditions, 67% of the radioactivity was recovered as {sup 14}CO{sub 2}: 2% was extracted with 50% methanol, and 24% was recovered by combustion of the sediment. Analysis of the methanol extract revealed that no pyridine could be detected in the inoculated sediment. In contrast, mineralization of pyridine by the native microflora in the sediment occurred much more slowly: After 7 days of incubation only 10% of the added radioactivity was recovered as {sup 14}CO{sub 2}. At an inoculum size of 2x10{sup 3} cells/g pyridine mineralization was not as effective as at an inoculum size of 2x10{sup 7} cells/g. It is presumed that suppression of the introduced bacteria by the native microflora of the sediment prevents degradation at a low inoculum size. Amending the sediment with nitrate and phosphate improved pyridine mineralization by the introduced bacterium. These findings demonstrate the feasibility of using soil inoculation anaerobically for the bioremediation of pyridine-polluted soils. (orig.).

  12. Viability of and Escherichia coli O157:H7 and Listeria monocytogenes in a delicatessen appetizer (yogurt-based) salad as affected by citrus extract (Citrox©) and storage temperature.

    Science.gov (United States)

    Tsiraki, Maria I; Yehia, Hany M; Elobeid, Tahra; Osaili, Tareq; Sakkas, Hercules; Savvaidis, Ioannis N

    2018-02-01

    The antimicrobial effect of citrus extract (at 1 mL/kg [C1] and 2 mL/kg [C2]) on naturally occurring microbiota and inoculated pathogens (E. coli O157:H7 and L. monocytogenes at ca. 6 log cfu/g) in the traditional Greek yogurt-based salad Tzatziki stored at 4, 10, or 21 °C, was examined. Lactic acid bacteria (LAB) were high (8.0-8.5 log cfu/g) and varied only minimally for both the control (untreated) and the citrus extract-treated salad samples, whereas the higher citrus extract concentration yielded the lowest yeast populations, irrespective of temperature, during the entire storage period. Populations of inoculated E. coli (6 log cfu/g) declined in both untreated and citrus extract-treated samples from day 0-70, 35, and 15 at 4, 10, and 21 °C, respectively. Citrus extract had a significant effect on the survival of the inoculated E. coli O157:H7, with reductions of 2.8-4.8 log cfu/g in the citrus extract-treated samples at the end of the storage period. Our data show that L. monocytogenes survived in both untreated and citrus extract-treated samples during the entire storage period, irrespective of the storage temperature. The higher concentration of citrus extract had a significant effect on the survival of L. monocytogenes in the treated samples, and reductions of 1.5-3.0 logs were noted on final day 70, 35 and 15 at 4, 10 and 21 °C, respectively. The results of our study demonstrated the potential of citrus extract as a natural compound that can control the growth of food-borne pathogenic bacteria, such as E. coli O157:H7 and L. monocytogenes in Tzatziki, a yogurt-based salad. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Assessment of Listeria sp. Interference Using a Molecular Assay To Detect Listeria monocytogenes in Food.

    Science.gov (United States)

    Zittermann, Sandra I; Stanghini, Brenda; See, Ryan Soo; Melano, Roberto G; Boleszczuk, Peter; Murphy, Allana; Maki, Anne; Mallo, Gustavo V

    2016-01-01

    Detection of Listeria monocytogenes in food is currently based on enrichment methods. When L. monocytogenes is present with other Listeria species in food, the species compete during the enrichment process. Overgrowth competition of the nonpathogenic Listeria species might result in false-negative results obtained with the current reference methods. This potential issue was noted when 50 food samples artificially spiked with L. monocytogenes were tested with a real-time PCR assay and Canada's current reference method, MFHPB-30. Eleven of the samples studied were from foods naturally contaminated with Listeria species other than those used for spiking. The real-time PCR assay detected L. monocytogenes in all 11 of these samples; however, only 6 of these samples were positive by the MFHPB-30 method. To determine whether L. monocytogenes detection can be affected by other species of the same genus due to competition, an L. monocytogenes strain and a Listeria innocua strain with a faster rate of growth in the enrichment broth were artificially coinoculated at different ratios into ground pork meat samples and cultured according to the MFHPB-30 method. L. monocytogenes was detected only by the MFHPB-30 method when L. monocytogenes/L. innocua ratios were 6.0 or higher. In contrast, using the same enrichments, the real-time PCR assay detected L. monocytogenes at ratios as low as 0.6. Taken together, these findings support the hypothesis that L. monocytogenes can be outcompeted by L. innocua during the MFHPB-30 enrichment phase. However, more reliable detection of L. monocytogenes in this situation can be achieved by a PCR-based method mainly because of its sensitivity.

  14. Post-processing application of chemical solutions for control of Listeria monocytogenes, cultured under different conditions, on commercial smoked sausage formulated with and without potassium lactate-sodium diacetate.

    Science.gov (United States)

    Geornaras, Ifigenia; Skandamis, Panagiotis N; Belk, Keith E; Scanga, John A; Kendall, Patricia A; Smith, Gary C; Sofos, John N

    2006-12-01

    This study evaluated post-processing chemical solutions for their antilisterial effects on commercial smoked sausage formulated with or without 1.5% potassium lactate plus 0.05% sodium diacetate, and contaminated (approximately 3-4 log cfu/cm(2)) with 10-strain composite Listeria monocytogenes inocula prepared under various conditions. Inoculated samples were left untreated, or were immersed (2 min, 25 +/- 2 degrees C) in solutions of acetic acid (2.5%), lactic acid (2.5%), potassium benzoate (5%) or Nisaplin (0.5%, equivalent to 5000 IU/ml of nisin) alone, and in sequence (Nisaplin followed by acetic acid, lactic acid or potassium benzoate), before vacuum packaging and storage at 10 degrees C (48 days). Acetic acid, lactic acid or potassium benzoate applied alone reduced initial L. monocytogenes populations by 0.4-1.5 log cfu/cm(2), while treatments including Nisaplin caused reductions of 2.1-3.3 log cfu/cm(2). L. monocytogenes on untreated sausage formulated with antimicrobials had a lag phase duration of 10.2 days and maximum specific growth rate (mu(max)) of 0.089 per day, compared to no lag phase and mu(max) of 0.300 per day for L. monocytogenes on untreated product that did not contain antimicrobials in the formulation. The immersion treatments inhibited growth of the pathogen for 4.9-14.8 days on sausage formulated without potassium lactate-sodium diacetate; however, in all cases significant (P meat processors in their efforts to select required regulatory alternatives for control of post-processing contamination in meat products.

  15. Time of action of 4.5 S RNA in Escherichia coli translation

    DEFF Research Database (Denmark)

    Brown, S

    1989-01-01

    A new class of suppressor mutants helps to define the role of 4.5 S RNA in translation. The suppressors reduce the requirement for 4.5 S RNA by increasing the intracellular concentration of uncharged tRNA. Suppression probably occurs by prolonging the period in which translating ribosomes have...... translocated but not yet released the uncharged tRNA, indicating that this is the point at which 4.5 S RNA enters translation. The release of 4.5 S RNA from polysomes is affected by antibiotics that inhibit protein synthesis. The antibiotic-sensitivity of this release indicates that 4.5 S RNA exits...... the ribosome following translocation and prior to release of protein synthesis elongation factor G. These results indicate that 4.5 S RNA acts immediately after ribosomal translocation. A model is proposed in which 4.5 S RNA stabilizes the post-translocation state by replacing 23 S ribosomal RNA as a binding...

  16. Mouse nucleolin binds to 4.5S RNAH, a small noncoding RNA

    International Nuclear Information System (INIS)

    Hirose, Yutaka; Harada, Fumio

    2008-01-01

    4.5S RNAH is a rodent-specific small noncoding RNA that exhibits extensive homology to the B1 short interspersed element. Although 4.5S RNAH is known to associate with cellular poly(A)-terminated RNAs and retroviral genomic RNAs, its function remains unclear. In this study, we analyzed 4.5S RNAH-binding proteins in mouse nuclear extracts using gel mobility shift and RNA-protein UV cross-linking assays. We found that at least nine distinct polypeptides (p170, p110, p93, p70, p48, p40, p34, p20, and p16.5) specifically interacted with 4.5S RNAHin vitro. Using anti-La antibody, p48 was identified as mouse La protein. To identify the other 4.5S RNAH-binding proteins, we performed expression cloning from a mouse cDNA library and obtained cDNA clones derived from nucleolin mRNA. We identified p110 as nucleolin using nucleolin-specific antibodies. UV cross-linking analysis using various deletion mutants of nucleolin indicated that the third of four tandem RNA recognition motifs is a major determinant for 4.5S RNAH recognition. Immunoprecipitation of nucleolin from the subcellular fractions of mouse cell extracts revealed that a portion of the endogenous 4.5S RNAH was associated with nucleolin and that this complex was located in both the nucleoplasm and nucleolus

  17. Xe N4,5O-OOO satellite Auger spectrum

    International Nuclear Information System (INIS)

    Partanen, L; Huttula, M; Heinaesmaeki, S; Aksela, H; Aksela, S

    2007-01-01

    The N 4,5 O 1,2,3 -O 1,2,3 O 2,3 O 2,3 Auger transitions, appearing as a satellite structure in the N 4,5 -OO Auger spectrum of xenon, were studied in detail. By measuring the N 4,5 O-OOO satellite Auger spectrum both below and above the 4p ionization threshold, we were able to separate the satellite production via the direct photo-double ionization and the Auger cascade from the 4p states. The N 3 -N 4,5 O 2,3 Coster-Kronig transitions and the subsequent N 4,5 O 2,3 -O 2,3 O 2,3 O 2,3 satellite Auger transitions were calculated using the HF wavefunctions and the most intense satellite lines were assigned. The Xe N 4,5 O-OOO satellite spectrum was compared with the previously studied Kr M 4,5 N-NNN satellite Auger spectrum. The 5s orbital in Xe was found to reveal more pronounced electron correlation than the 4s orbital in Kr

  18. Is inositol (1,3,4,5)-tetrakisphosphate a new second messenger?

    International Nuclear Information System (INIS)

    Hansen, C.A.; Williamson, J.R.

    1986-01-01

    Hormone-stimulated hydrolysis of inositol (Ins) lipids results in the rapid formation of Ins(1,4,5)P 3 , the second messenger for intracellular Ca 2+ mobilization. Recently, a more polar inositol phosphate, Ins(1,3,4,5)P 4 as well as its probable hydrolysis product Ins(1,3,4)P 3 have been reported to accumulate in carbachol-stimulated brain slices. Vasopressin addition to hepatocytes prelabeled with [ 3 H]-Ins also showed a rapid increase of Ins(1,3,4,5)P 4 , which was similar to that of Ins(1,4,5)P 3 , while the accumulation of Ins(1,3,4)P 3 was slower. In order to examine whether Ins(1,3,4,5)P 4 has any functional effects on Ca 2+ homeostasis, it was synthesized enzymatically from [ 3 H]-Ins(1,4,5)P 3 using a partially purified phosphoinositol kinase activity from rat brain cortex. [ 3 H]-labeled inositol phosphates were separated by anion exchange chromatography and analyzed by HPLC using ammonium formate/phosphoric acid gradient elution. Preliminary experiments indicate that Ins(1,3,4,5)P 4 up to 10 μM does not release Ca 2+ from vesicular pools in saponin-permeabilized hepatocytes. It has a slight inhibitory effect on Ins(1,4,5)P 3 -induced Ca 2+ release. The effect of Ins(1,3,4,5)P 4 on plasma membrane Ca 2+ fluxes are presently being investigated

  19. Edaravone with and without .6 Mg/Kg Alteplase within 4.5 Hours after Ischemic Stroke: A Prospective Cohort Study (PROTECT4.5).

    Science.gov (United States)

    Yamaguchi, Takenori; Awano, Hideto; Matsuda, Hiroaki; Tanahashi, Norio

    2017-04-01

    Edaravone is widely used to treat acute ischemic stroke (AIS) within 24 hours of onset. We aimed to evaluate current edaravone treatment practices and the efficacy and safety of edaravone used with recombinant tissue plasminogen activator (tPA) in AIS patients within 4.5 hours of onset. The results were compared with those of the Safe Implementation of Treatments in Stroke-International Stroke Thrombolysis Registry (SITS-ISTR) study. PROTECT4.5 was a prospective observational study conducted from April 2010 to March 2013 in Japan. The primary end points were favorable outcomes (modified Rankin Scale score [mRS] 0-1) at 3 months after onset and incidence of symptomatic intracranial hemorrhage (sICH) within 36 hours of treatment. For comparison with SITS-ISTR, patients were categorized based on the time from onset to treatment (within 3 hours of and 3-4.5 hours after onset) and baseline National Institutes of Health Stroke Scale score (NIHSS). Among the 11,384 registered patients, 11,126 and 8274 patients were included in the safety and efficacy analysis populations, respectively. The proportions of patients with mRS 0-1 receiving edaravone alone and edaravone + tPA were 51.3% (95% confidence interval, 49.7%-52.8%) and 39.0% (37.6%-40.5%), respectively. The incidence of sICH within 36 hours after tPA treatment (edaravone + tPA group) was 1.6% (1.3%-2.0%). When compared with the SITS-ISTR results, those treated with edaravone + tPA appeared to show better outcomes in patients with NIHSS score ≥16. The efficacy and safety of edaravone combined with tPA and administered within 4.5 hours of AIS onset were demonstrated with numerically lower incidence of sICH and better outcomes. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    FAMA

    2015-09-30

    Sep 30, 2015 ... AMF on root colonization, biomass production, mycorrhizal dependency (MD) and shoot mineral ... four months of growth in a sterilized soil and greenhouse conditions, grasses inoculated with AMF ..... Quetta, Pakistan.

  1. Effects of bacterial inoculation on the fermentation characteristics ...

    African Journals Online (AJOL)

    DNkosi

    2016-05-11

    May 11, 2016 ... The chopped forages were treated with or without the bacterial .... packed loosely in an open plastic jar, which was covered with two ..... be because LD inoculant contains enzymes that may be capable of degrading fibre.

  2. Treatment of dairy wastewater in UASB reactors inoculated with ...

    African Journals Online (AJOL)

    Treatment of dairy wastewater in UASB reactors inoculated with flocculent biomass. ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... of using flocculent sludge in UASB reactors applied to the treatment of dairy ...

  3. Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal ...

    African Journals Online (AJOL)

    Inoculation of Ceratonia siliqua L. with native arbuscular mycorrhizal fungi mixture improves seedling establishment under greenhouse conditions. Ouahmane Lahcen, Ndoye Ibrahima, Morino Abdessadek, Ferradous Abderrahim, Sfairi Youssef, Al Faddy Mohamed Najib, Abourouh Mohamed ...

  4. Effect of salinity and inoculation with Azosprillium on carbohydrate ...

    African Journals Online (AJOL)

    Jane

    2011-08-17

    Aug 17, 2011 ... Inoculation reduced harmful effects of salinity especially on mean kernel weight and grain ... considered to play a key role in stress induced metabolic processes and membrane ..... osmoregulation. Conclusion. Increase in ...

  5. Effects of genotype x bradyrhizobium inoculation or x fertilizer n ...

    African Journals Online (AJOL)

    Genotype x inoculation interaction was significant only for protein and oil content in one year. .... main-plot factor. ... components and expected genetic gains invoiving yield srrnin. ... Combined analysis of the cu ltivar experiment was carried.

  6. Effects of Rhizobuim leguminosarum inoculation on the growth and ...

    African Journals Online (AJOL)

    g per plant in 2008 and 2009 seasons, respectively. The findings suggested that inoculation of Mucuna flagellipies with Rhizobium is beneficial and produced high seed yield and could be use as biofertilizer an alternative to nitrogen fertilizer.

  7. Co-inoculation effects of Bradyrhizobium japonicum and ...

    African Journals Online (AJOL)

    Corporate Edition

    2013-05-15

    . 2851. MATERIALS AND METHODS. Bacterial strains, media and growth conditions. Two B. japonicum strains of CB 1809 and USDA 110 those currently used in rhizobial inoculants production for soybean at the. Department ...

  8. effects of rhizobuim leguminosarum inoculation on the growth and ...

    African Journals Online (AJOL)

    user

    beneficial symbiotic microorganisms into the plant. Rhizosphere ... Rhizobium strains in the yeast manitol broth were ... inoculants contained sixteen (16) colonies of Rhizobium leguminosarum bacterial cells per milliliter (ml) of the yeast ...

  9. Calcium Directly Regulates Phosphatidylinositol 4,5-Bisphosphate Headgroup Conformation and Recognition

    DEFF Research Database (Denmark)

    Bilkova, Eva; Pleskot, Roman; Rissanen, Sami

    2017-01-01

    ), is completely inhibited in the presence of Ca2+, while Mg2+ has no effect with 100 nm liposomes and modest effect with giant unilamellar vesicles. Consistent with biochemical data, vibrational sum frequency spectroscopy and atomistic molecular dynamics simulations reveal how Ca2+ binding to the PI(4,5)P2...... phosphoinositide clustering, little is known about the molecular basis for this or its significance in cellular signaling. Here, we study the direct interaction of Ca2+ with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), the main lipid marker of the plasma membrane. Electrokinetic potential measurements of PI...

  10. Diversity assessment of Listeria monocytogenes biofilm formation: Impact of growth condition, serotype and strain origin

    NARCIS (Netherlands)

    Kadam, S.R.; Besten, den H.M.W.; Veen, van der S.; Zwietering, M.H.; Moezelaar, R.; Abee, T.

    2013-01-01

    The foodborne pathogen Listeria monocytogenes has the ability to produce biofilms in food-processing environments and then contaminate food products, which is a major concern for food safety. The biofilm forming behavior of 143 L. monocytogenes strains was determined in four different media that

  11. A novel suicide plasmid for efficient gene mutation in Listeria monocytogenes

    Science.gov (United States)

    Although several plasmids have been used in Listeria monocytogenes for generating mutants by allelic exchange, construction of L. monocytogenes mutants has been inefficient due to lack of effective selection markers for first and second recombination events. To address this problem, we have develope...

  12. Environmental prevalence and persistence of Listeria monocytogenes in cold-smoked trout processing plants

    Science.gov (United States)

    The presence of Listeria monocytogenes on the surfaces of equipment and workers' hands during different production stages, as well as on fish skin and meat during processing and storage of cold-smoked trout, was investigated. Listeria monocytogenes was recovered from 10 (6.06%) of a total 165 cotto...

  13. Genome Sequences of Two Listeria monocytogenes Strains from Nectarines Associated with Listeriosis in 2014

    Science.gov (United States)

    Lu, Chunye; Marjanovic, Olivera; Kiang, David

    2017-01-01

    ABSTRACT Listeria monocytogenes is an important foodborne pathogen. Here, we present the annotated whole genome of Listeria monocytogenes strains F14M01297-C2 and F14M01297-C4, isolated from nectarines distributed by a packing facility in California during an investigation of listeriosis associated with stone fruit in 2014. PMID:28729255

  14. The occurrence, transmission, virulence and antibiotic resistance of Listeria monocytogenes in fish processing plant.

    Science.gov (United States)

    Skowron, Krzysztof; Kwiecińska-Piróg, Joanna; Grudlewska, Katarzyna; Świeca, Agnieszka; Paluszak, Zbigniew; Bauza-Kaszewska, Justyna; Wałecka-Zacharska, Ewa; Gospodarek-Komkowska, Eugenia

    2018-06-13

    The aim of this research was to investigate the occurrence of Listeria monocytogenes in fish and fish processing plant and to determine their transmission, virulence and antibiotic resistance. L. monocytogenes was isolated according to the ISO 11290-1. The identification of L. monocytogenes was confirmed by multiplex PCR method. Genetic similarity of L. monocytogenes strains was determined with the Pulsed-Filed Gene Electrophoresis (PFGE) method. The multiplex PCR was used for identification of L. monocytogenes serogroups and detection of selected virulence genes (actA, fbpA, hlyA, iap, inlA, inlB, mpl, plcA, plcB, prfA). The L. monocytogens isolates susceptibility to penicillin, ampicillin, meropenem, erythromycin, trimethoprim/sulfamethoxazole was evaluated with disc diffusion method according to EUCAST v. 7.1. The presence of 237 L. monocytogenes isolates (before genetic similarity assessment) in 614 examined samples was confirmed. After strain differentiation by PFGE techniques the presence of 161 genetically different strains were confirmed. The genetic similarity of the examined isolates suggested that the source of the L. monocytogenes strains were fishes originating from farms. All tested strains possessed all detected virulence genes. Among examined strains, the most (26, 38.6%) belonged to the group 1/2a-3a. The most of tested strains were resistant to erythromycin (47.1%) and trimethoprim/sulfamethoxazole (47.1%). Copyright © 2018. Published by Elsevier B.V.

  15. A dynamical systems approach to actin-based motility in Listeria monocytogenes

    Science.gov (United States)

    Hotton, S.

    2010-11-01

    A simple kinematic model for the trajectories of Listeria monocytogenes is generalized to a dynamical system rich enough to exhibit the resonant Hopf bifurcation structure of excitable media and simple enough to be studied geometrically. It is shown how L. monocytogenes trajectories and meandering spiral waves are organized by the same type of attracting set.

  16. A multiplex PCR for detection of Listeria monocytogenes and its lineages.

    Science.gov (United States)

    Rawool, Deepak B; Doijad, Swapnil P; Poharkar, Krupali V; Negi, Mamta; Kale, Satyajit B; Malik, S V S; Kurkure, Nitin V; Chakraborty, Trinad; Barbuddhe, Sukhadeo B

    2016-11-01

    A novel multiplex PCR assay was developed to identify genus Listeria, and discriminate Listeria monocytogenes and its major lineages (LI, LII, LIII). This assay is a rapid and inexpensive subtyping method for screening and characterization of L. monocytogenes. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Isolation and characterization of an atypical Listeria monocytogenes associated with a canine urinary tract infection

    Science.gov (United States)

    Listeria monocytogenes, a well-described cause of encephalitis and abortion in ruminants and of food-borne illness in humans, is rarely associated with disease in companion animals. A case of urinary tract infection associated with an atypical, weakly hemolytic L. monocytogenes strain is described i...

  18. Albendazole inhibits Pneumocystis carinii proliferation in inoculated immunosuppressed mice.

    OpenAIRE

    Bartlett, M S; Edlind, T D; Lee, C H; Dean, R; Queener, S F; Shaw, M M; Smith, J W

    1994-01-01

    Albendazole, a benzimidazole derivative widely used for treating helminth infections, was successfully used to treat and prevent development of Pneumocystis carinii pneumonia in transtracheally inoculated immunosuppressed mice. For treatment, 3 weeks postinoculation, albendazole at 300 and 600 mg/kg of body weight per day was administered in food for 3 weeks. For prophylaxis, albendazole was begun on the same day as inoculation at 300 mg/kg/day for 7 days, and then the dose was reduced to 150...

  19. Conditions Affecting Shelf-Life of Inoculated Legume Seed

    Directory of Open Access Journals (Sweden)

    Greg Gemell

    2012-02-01

    Full Text Available Microbial inoculants are becoming more available as sustainable alternatives to fertilizers and other agrichemicals in broad-acre cropping. However, with the exception of legume inoculants little is understood about effective delivery and survival of the inoculum. Legume inoculants are applied to both seed and soil but seed inoculation is the most economical technique. Large quantities of pasture seed in Australia are inoculated by commercial seed coating companies, but the long-term survival of seed-applied inoculum is variable and monitoring of viability requires specialist microbiology skills and facilities. The aim of our research was to define optimum storage conditions for survival of rhizobia on legume seed and evaluate water activity as a means of monitoring shelf-life. The relationship between survival and water activity varied according to seed species, inoculum preparation, coating ingredients, initial water activity and time suggesting that storage conditions would need to be defined for each different combination. Although drying seeds after coating significantly reduced viable numbers of rhizobia, survival of rhizobia on dried commercially coated lucerne seed after 11 weeks was less variable than seeds that had not been dried. The highest numbers were maintained when seeds remained dry with water activities of between 0.47 and 0.38. The quality of inoculated seed could be improved by reducing the death rate of inoculum during preparation and providing optimum storage conditions for long-term survival.

  20. Comparative experimental infection of Listeria monocytogenes and Listeria ivanovii in bovine trophoblasts.

    Science.gov (United States)

    Rocha, Cláudia E; Mol, Juliana P S; Garcia, Luize N N; Costa, Luciana F; Santos, Renato L; Paixão, Tatiane A

    2017-01-01

    Listeria monocytogenes is a Gram-positive, facultative intracellular and invasive bacterium that has tropism to the placenta, and causes fetal morbidity and mortality in several mammalian species. While infection with L. monocytogenes and L. ivanovii are known as important causes of abortion and reproductive failure in cattle, the pathogenesis of maternal-fetal listeriosis in this species is poorly known. This study used the bovine chorioallantoic membrane explant model to investigate the kinetics of L. monocytogenes, L. ivanovii, and L. innocua infections in bovine trophoblastic cells for up to 8 h post infection. L. monocytogenes and L. ivanovii were able to invade and multiply in trophoblastic cells without causing cell death or inducing expression of pro-inflammatory genes. Although L. innocua was unable to multiply in bovine trophoblastic cells, it induced transcription of the pro-inflammatory mediator CXCL6. This study demonstrated for the first time the susceptibility of bovine trophoblastic cells to L. monocytogenes and L. ivanovii infection.

  1. Survival of Bactericidal Antibiotic Treatment by a Persister Subpopulation of Listeria monocytogenes

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Ng, Yin; Gram, Lone

    2013-01-01

    Listeria monocytogenes can cause the serious infection listeriosis, which despite antibiotic treatment has a high mortality. Understanding the response of L. monocytogenes to antibiotic exposure is therefore important to ensure treatment success. Some bacteria survive antibiotic treatment...... by formation of persisters, which are a dormant antibiotic-tolerant subpopulation. The purpose of this study was to determine whether L. monocytogenes can form persisters and how bacterial physiology affects the number of persisters in the population. A stationary-phase culture of L. monocytogenes was adjusted...... that eradication of persisters is possible. Our study adds L. monocytogenes to the list of bacterial species capable of surviving bactericidal antibiotics in a dormant stage, and this persister phenomenon should be borne in mind when developing treatment regimens....

  2. A study on the kinetic behavior of Listeria monocytogenes in ice cream stored under static and dynamic chilling and freezing conditions.

    Science.gov (United States)

    Gougouli, M; Angelidis, A S; Koutsoumanis, K

    2008-02-01

    The kinetic behavior of Listeria monocytogenes in 2 commercial ice cream products (A and B) that were inoculated and stored under static chilling (4 to 16 degrees C), static freezing (-5 to -33 degrees C), dynamic chilling, and dynamic chilling-freezing conditions was studied, simulating conditions of the aging process and of normal or abuse conditions during distribution and storage. The ice cream products A and B had different compositions but similar pH (6.50 and 6.67, respectively) and water activity (0.957 and 0.965, respectively) values. For both chilling and freezing conditions, the kinetic behavior of the pathogen was similar in the 2 products, indicating that the pH and water activity, together with temperature, were the main factors controlling growth. Under chilling conditions, L. monocytogenes grew well at all temperatures tested. Under freezing conditions, no significant changes in the population of the pathogen were observed throughout a 90-d storage period for either of the inoculum levels tested (10(3) and 10(6) cfu/g). Growth data from chilled storage conditions were fitted to a mathematical model, and the calculated maximum specific growth rate was modeled as a function of temperature by using a square root model. The model was further validated under dynamic chilling and dynamic chilling-freezing conditions by using 4 different storage temperature scenarios. Under dynamic chilling conditions, the model accurately predicted the growth of the pathogen in both products, with 99.5% of the predictions lying within the +/- 20% relative error zone. The results from the chilling-freezing storage experiments showed that the pathogen was able to initiate growth within a very short time after a temperature upshift from freezing to chilling temperatures. This indicates that the freezing conditions did not cause a severe stress in L. monocytogenes cells capable of leading to a significant "additional" lag phase during the subsequent growth of the pathogen at

  3. Survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on raw peanut and pecan kernels stored at -24, 4, and 22°C.

    Science.gov (United States)

    Brar, Pardeepinder K; Proano, Lisseth G; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D

    2015-02-01

    Cocktails of lawn-collected cells were used to determine the survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes on the surface of raw peanut and pecan kernels. Kernels were inoculated with mixtures of four to five strains at 3 or 6 log CFU/g, dried at room temperature, and then stored at -24 ± 1, 4 ± 2, and 22 ± 1°C for 28 or 365 days. In most cases, rates of decline of the pathogens did not differ significantly between the two inoculum concentrations in the 28-day study. At 6 log CFU/g, populations of all pathogens were reduced by 0.5 to 1.6 log CFU/g during an initial 3-day drying period on both peanuts and pecans. The moisture content of peanuts and pecans remained stable at -24 ± 1 and 22 ± 1°C; at 4 ± 2°C, the moisture content increased from 3.8 to 5.6% on peanuts and from 2.6 to 3% on pecans over 365 days. Pathogen populations were stable on pecans stored under frozen and refrigerated conditions, except for L. monocytogenes, which declined at a rate of 0.03 log CFU/g/30 days at 4 ± 2°C. Salmonella populations were stable on peanuts stored at -24 ± 1 and 4 ± 2°C, but E. coli O157:H7 and L. monocytogenes declined at rates of 0.03 to 0.12 log CFU/g/30 days. At 22 ± 1°C, Salmonella, E. coli O157:H7, and L. monocytogenes declined at a rate of 0.22, 0.37, and 0.59 log CFU/g/30 days, respectively, on peanuts, and at 0.15, 0.34, and 1.17 log CFU/g/30 days, respectively, on pecans. Salmonella counts were above the limit of detection (0.30 log CFU/g) throughout the study. In most cases during storage, counts obtained from pecans were higher than from peanuts.

  4. INTEGRASI ALGORITMA POHON KEPUTUSAN C4.5 YANG DIKEMBANGKAN KE DALAM OBJECT-RELATIONAL DBMS

    Directory of Open Access Journals (Sweden)

    Veronica S. Moertini

    2007-07-01

    Full Text Available Integrasi teknik-teknik data mining ke dalam DBMS, khususnya Object-Relational DBMS (ORDBMS, masih merupakan bidang penelitian yang aktif. Isu utama pada integrasi ini adalah: peleburan algoritma data mining ke dalam ORDBMS dengan memanfaatkan fitur-fiturnya untuk memperbaiki kualitas teknik tersebut. Pada penelitian ini, algoritma klasifikasi C4.5 dikembangkan dengan pendekatan aljabar relasional dan diintegrasikan ke dalam ORDBMS sebagai prosedur-prosedur tersimpan Java dan berbasis SQL, dengan tujuan untuk meningkatkan skalabilitas dan efisiensinya. Hasil eksperimen menunjukkan bahwa algoritma yang sudah diintegrasikan berhasil memperbaiki skalabilitas dan pada kasus khusus juga memperbaiki  efisiensi.   Kata kunci: pengembangan algoritma C.5, integrasi C4.5 ke dalam Object-Relational DBMS, algoritma C4.5, perbaikan skalabilitas C4.5.

  5. Quantitative uranium speciation with U M{sub 4,5}-edge HERFD absorption spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kvashnina, Kristina O.; Rossberg, Andre [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Molecular Structures

    2017-06-01

    This report gives a brief description of the quantitative uranium speciation performed by iterative transformation factor analysis (ITFA) of High Energy Resolution X-ray Fluorescence Detection (HERFD) data collected at the M{sub 4,5} edge.

  6. The 4.5 S RNA gene of Escherichia coli is essential for cell growth

    DEFF Research Database (Denmark)

    Brown, S; Fournier, M J

    1984-01-01

    The Escherichia coli gene coding for the metabolically stable 4.5 S RNA (ffs) has been shown to be required for cell viability. Essentiality was demonstrated by examining the recombination behavior of substitution mutations of ffs generated in vitro. Substitution mutants of ffs are able to replace...... the chromosomal allele only in the presence of a second, intact copy of ffs. Independent evidence of essentiality and the finding that 4.5 S RNA is important for protein synthetic activity came from characterization of cells dependent on the lac operon inducer isopropyl-beta-D-thiogalactoside for ffs gene...... expression. Here, a strain dependent on isopropyl-beta-D-thiogalactoside for 4.5 S RNA synthesis was developed by inactivation of the chromosomal ffs allele and lysogenization by a lambda phage containing 4.5 S DNA fused to a hybrid trp-lac promoter. Withdrawal of the thiogalactoside leads to a deficiency...

  7. Application of preprocessing filtering on Decision Tree C4.5 and rough set theory

    Science.gov (United States)

    Chan, Joseph C. C.; Lin, Tsau Y.

    2001-03-01

    This paper compares two artificial intelligence methods: the Decision Tree C4.5 and Rough Set Theory on the stock market data. The Decision Tree C4.5 is reviewed with the Rough Set Theory. An enhanced window application is developed to facilitate the pre-processing filtering by introducing the feature (attribute) transformations, which allows users to input formulas and create new attributes. Also, the application produces three varieties of data set with delaying, averaging, and summation. The results prove the improvement of pre-processing by applying feature (attribute) transformations on Decision Tree C4.5. Moreover, the comparison between Decision Tree C4.5 and Rough Set Theory is based on the clarity, automation, accuracy, dimensionality, raw data, and speed, which is supported by the rules sets generated by both algorithms on three different sets of data.

  8. Signal-dependent Hydrolysis of Phosphatidylinositol 4,5-Bisphosphate without Activation of Phospholipase C

    Science.gov (United States)

    Lev, Shaya; Katz, Ben; Tzarfaty, Vered; Minke, Baruch

    2012-01-01

    In Drosophila, a phospholipase C (PLC)-mediated signaling cascade, couples photo-excitation of rhodopsin to the opening of the transient receptor potential (TRP) and TRP-like (TRPL) channels. A lipid product of PLC, diacylglycerol (DAG), and its metabolites, polyunsaturated fatty acids (PUFAs) may function as second messengers of channel activation. However, how can one separate between the increase in putative second messengers, change in pH, and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) depletion when exploring the TRPL gating mechanism? To answer this question we co-expressed the TRPL channels together with the muscarinic (M1) receptor, enabling the openings of TRPL channels via G-protein activation of PLC. To dissect PLC activation of TRPL into its molecular components, we used a powerful method that reduced plasma membrane-associated PI(4,5)P2 in HEK cells within seconds without activating PLC. Upon the addition of a dimerizing drug, PI(4,5)P2 was selectively hydrolyzed in the cell membrane without producing DAG, inositol trisphosphate, or calcium signals. We show that PI(4,5)P2 is not an inhibitor of TRPL channel activation. PI(4,5)P2 hydrolysis combined with either acidification or application of DAG analogs failed to activate the channels, whereas PUFA did activate the channels. Moreover, a reduction in PI(4,5)P2 levels or inhibition of DAG lipase during PLC activity suppressed the PLC-activated TRPL current. This suggests that PI(4,5)P2 is a crucial substrate for PLC-mediated activation of the channels, whereas PUFA may function as the channel activator. Together, this study defines a narrow range of possible mechanisms for TRPL gating. PMID:22065576

  9. Differential Diagnosis Knowledge Building by Using CUC-C4.5 Framework

    OpenAIRE

    Kusrini; Sri Hartati; Retantyo Wardoyo; Agus Harjoko

    2010-01-01

    Problem statement: The Case Based Reasoning (CBR) method can be implemented in differential diagnosis analysis. C4.5 algorithm has been commonly used to help the method's knowledge building process. This process is completed by constructing decision tree from previously handled cases data. The C4.5 algorithm itself can be used with an assumption that all the cases has an exact and equal truth value thus have an exact contribution in decision tree building process. However, the decision makers...

  10. Generator Pohon Keputusan Dengan Menerapkan Algoritma C4.5 Untuk Program Konsultasi

    OpenAIRE

    Kharis, Irma; Delima, Rosa; Purwadi, Joko

    2013-01-01

    C4.5 algorithm is used to simplify decision tree from decision table by generating decision tree from an existing decision tree. With this algorithm, knowledge base in the decision table can be simplified. This research will build a consultation program using C4.5 algorithm which is called decision tree generator. Decision tree generator provides inference facility and a user interface for consultation. The user is required to build a knowledge base first, and the application will generate u...

  11. Antimalarial peroxides: the first intramolecular 1,2,4,5-tetraoxane

    Directory of Open Access Journals (Sweden)

    BOGDAN A. SOLAJA

    2002-07-01

    Full Text Available An intramolecular steroidal 1,2,4,5-tetraoxane has been synthesised in six steps starting from methyl 3-oxo-7a,12a-diacetoxy-5b-cholan-24-oate. The synthesised 1,2,4,5-tetraoxane has moderate in vitro antimalarial activity against P. falciparum strains (IC50 (D6 = 0.35 mg/mL; IC50 (W2 = 0.29 mg/mL.

  12. Loss of endocytic clathrin-coated pits upon acute depletion of phosphatidylinositol 4,5-bisphosphate.

    Science.gov (United States)

    Zoncu, Roberto; Perera, Rushika M; Sebastian, Rafael; Nakatsu, Fubito; Chen, Hong; Balla, Tamas; Ayala, Guillermo; Toomre, Derek; De Camilli, Pietro V

    2007-03-06

    Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], a phosphoinositide concentrated predominantly in the plasma membrane, binds endocytic clathrin adaptors, many of their accessory factors, and a variety of actin-regulatory proteins. Here we have used fluorescent fusion proteins and total internal reflection fluorescence microscopy to investigate the effect of acute PI(4,5)P(2) breakdown on the dynamics of endocytic clathrin-coated pit components and of the actin regulatory complex, Arp2/3. PI(4,5)P(2) breakdown was achieved by the inducible recruitment to the plasma membrane of an inositol 5-phosphatase module through the rapamycin/FRB/FKBP system or by treatment with ionomycin. PI(4,5)P(2) depletion resulted in a dramatic loss of clathrin puncta, which correlated with a massive dissociation of endocytic adaptors from the plasma membrane. Remaining clathrin spots at the cell surface had only weak fluorescence and were static over time. Dynamin and the p20 subunit of the Arp2/3 actin regulatory complex, which were concentrated at late-stage clathrin-coated pits and in lamellipodia, also dissociated from the plasma membrane, and these changes correlated with an arrest of motility at the cell edge. These findings demonstrate the critical importance of PI(4,5)P(2) in clathrin coat dynamics and Arp2/3-dependent actin regulation.

  13. Simulation of Soil Frost and Thaw Fronts Dynamics with Community Land Model 4.5

    Science.gov (United States)

    Gao, J.; Xie, Z.

    2016-12-01

    Freeze-thaw processes in soils, including changes in frost and thaw fronts (FTFs) , are important physical processes. The movement of FTFs affects soil water and thermal characteristics, as well as energy and water exchanges between land surface and the atmosphere, and then the land surface hydrothermal process. In this study, a two-directional freeze and thaw algorithm for simulating FTFs is incorporated into the community land surface model CLM4.5, which is called CLM4.5-FTF. The simulated FTFs depth and soil temperature of CLM4.5-FTF compared well with the observed data both in D66 station (permafrost) and Hulugou station (seasonally frozen soil). Because the soil temperature profile within a soil layer can be estimated according to the position of FTFs, CLM4.5 performed better in soil temperature simulation. Permafrost and seasonally frozen ground conditions in China from 1980 to 2010 were simulated using the CLM4.5-FTF. Numerical experiments show that the spatial distribution of simulated maximum frost depth by CLM4.5-FTF has seasonal variation obviously. Significant positive active-layer depth trends for permafrost regions and negative maximum freezing depth trends for seasonal frozen soil regions are simulated in response to positive air temperature trends except west of Black Sea.

  14. Genetic diversity of symbiotic Bradyrhizobium elkanii populations recovered from inoculated and non-inoculated Acacia mangium field trials in Brazil.

    Science.gov (United States)

    Perrineau, M M; Le Roux, C; de Faria, S M; de Carvalho Balieiro, F; Galiana, A; Prin, Y; Béna, G

    2011-07-01

    Acacia mangium is a legume tree native to Australasia. Since the eighties, it has been introduced into many tropical countries, especially in a context of industrial plantations. Many field trials have been set up to test the effects of controlled inoculation with selected symbiotic bacteria versus natural colonization with indigenous strains. In the introduction areas, A. mangium trees spontaneously nodulate with local and often ineffective bacteria. When inoculated, the persistence of inoculants and possible genetic recombination with local strains remain to be explored. The aim of this study was to describe the genetic diversity of bacteria spontaneously nodulating A. mangium in Brazil and to evaluate the persistence of selected strains used as inoculants. Three different sites, several hundred kilometers apart, were studied, with inoculated and non-inoculated plots in two of them. Seventy-nine strains were isolated from nodules and sequenced on three housekeeping genes (glnII, dnaK and recA) and one symbiotic gene (nodA). All but one of the strains belonged to the Bradyrhizobium elkanii species. A single case of housekeeping gene transfer was detected among the 79 strains, suggesting an extremely low rate of recombination within B. elkanii, whereas the nodulation gene nodA was found to be frequently transferred. The fate of the inoculant strains varied depending on the site, with a complete disappearance in one case, and persistence in another. We compared our results with the sister species Bradyrhizobium japonicum, both in terms of population genetics and inoculant strain destiny. Copyright © 2011 Elsevier GmbH. All rights reserved.

  15. Biofilm formation on Conservolea natural black olives during single and combined inoculation with a functional Lactobacillus pentosus starter culture.

    Science.gov (United States)

    Grounta, Athena; Doulgeraki, Agapi I; Nychas, George-John E; Panagou, Efstathios Z

    2016-06-01

    The potential of biofilm formation of multifunctional starters Lactobacillus pentosus B281 and Pichia membranifaciens M3A during inoculated fermentation of Conservolea natural black olives according to Greek-style processing was investigated. Olives were directly brined in 8% (w/v) NaCl following three fermentation procedures namely, i) spontaneous fermentation, ii) inoculated fermentation with L. pentosus B281, and iii) co-inoculated fermentation with L. pentosus B281 and P. membranifaciens M3A. Lactic acid bacteria (LAB) and yeasts were monitored on olives by plate counting for a period of 153 days, whereas the survival of the inoculated strains was confirmed by Pulsed Field Gel Electrophoresis (PFGE) and Restriction Fragment Length Polymorphism (RFLP) analysis. Inoculated fermentation with L. pentosus B281 with/without the presence of the yeast resulted in higher acidification of the brine compared to the spontaneous process where no indigenous LAB could be enumerated. The population of LAB on olives ranged between 5.5 and 6.5 log CFU/g and it was maintained at higher levels compared to yeasts (3.5-4.5 log CFU/g) throughout the process. PFGE analysis revealed that L. pentosus B281 could successfully colonize the surface of black olives presenting high recovery rate (100%) at the end of fermentation in contrast to P. membranifaciens M3A that was successfully recovered (42%) only after 72 days of the process. The obtained results provide interesting perspectives for the production of natural black olives with functional properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Elimination of Listeria inoculated in ready-to-eat carrots by combination of antimicrobial coating and γ-irradiation

    International Nuclear Information System (INIS)

    Turgis, Mélanie; Millette, Mathieu; Salmieri, Stéphane; Lacroix, Monique

    2012-01-01

    A combined treatment of an edible coating composed of trans-cinnamaldehyde (TCN; 0.5% p/p) with γ-irradiation was investigated against Listeria inoculated in peeled mini-carrots. First, the D 10 value (γ-irradiation dose required to eliminate 90% of the bacterial population) of TCN was evaluated under air. This treatment resulted in a 3.66-fold increase in relative bacterial radiosensitivity (RBR) as compared to the control without antimicrobial coating. Secondly, the shelf life of mini-carrots during 21 day of storage at 4 °C was studied. Antimicrobial coating containing TCN was assayed in combination with two irradiation doses (0.25 and 0.5 kGy). Results suggested that the inactive coating did not have any antimicrobial effect against Listeria while the coating containing TCN resulted in a 1.29 log reduction in carrots packed under air after 21 days of storage. Hence, these observations indicated that the combination of irradiation with antimicrobial coating played an important role in enhancing the radiosensitization of Listeria to γ-irradiation. - Highlights: ► Synergistic effect of essential oils and γ-radiation against food pathogens. ► Reducing any undesirable organoleptic impact due to high concentration of EOs. ► Potential in controlling food pathogens and food spoilage bacteria in food. ► Elimination of Listeria monocytogenes in the carrots during the storage.

  17. Cytokine profile and natural killer cell activity in Listeria monocytogenes infected mice treated orally with Petiveria alliacea extract.

    Science.gov (United States)

    Queiroz, M L; Quadros, M R; Santos, L M

    2000-08-01

    In this work, we investigated the effects of Petiveria alliacea extract on the production of Th1-type and Th2-type cytokines and on NK cells activity in normal and Listeria monocytogenes infected mice. Our results demonstrated that in normal/non-infected mice P. alliacea administration led to increased levels of Interleukin-2 (IL-2). The infection alone enhanced INF-gamma levels and NK cell activity at 48 and 72 hours of infection. The treatment with five consecutive doses of 1000 mg/kg/day of P. alliacea extract, given previously to infection, led to further increases in IL-2 levels, in relation to normal/non-infected/P. alliacea treated controls, and in INF-gamma levels at 72 h of infection, compared to infected mice. On the other hand, the production of IL-4 and IL-10 were not altered either by the infection or by the treatment with P. alliacea extract. NK cells activity increased at 48 h and 72 h following the inoculation of the bacteria. When mice were treated with P. alliacea previously to infection, NK activity was higher than that observed at 48 h, 72 h and 120 h of infection in the infected animal. Based on these findings we suggest that P. alliacea up-regulates anti-bacterial immune response by enhancing both Th1 function and the activity of NK cells.

  18. Phosphatidylinositol 3,4,5-trisphosphate modulation in SHIP2-deficient mouse embryonic fibroblasts.

    Science.gov (United States)

    Blero, Daniel; Zhang, Jing; Pesesse, Xavier; Payrastre, Bernard; Dumont, Jacques E; Schurmans, Stéphane; Erneux, Christophe

    2005-05-01

    SHIP2, the ubiquitous SH2 domain containing inositol 5-phosphatase, includes a series of protein interacting domains and has the ability to dephosphorylate phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)]in vitro. The present study, which was undertaken to evaluate the impact of SHIP2 on PtdIns(3,4,5)P(3) levels, was performed in a mouse embryonic fibroblast (MEF) model using SHIP2 deficient (-/-) MEF cells derived from knockout mice. PtdIns(3,4,5)P(3) was upregulated in serum stimulated -/- MEF cells as compared to +/+ MEF cells. Although the absence of SHIP2 had no effect on basal PtdIns(3,4,5)P(3) levels, we show here that this lipid was significantly upregulated in SHIP2 -/- cells but only after short-term (i.e. 5-10 min) incubation with serum. The difference in PtdIns(3,4,5)P(3) levels in heterozygous fibroblast cells was intermediate between the +/+ and the -/- cells. In our model, insulin-like growth factor-1 stimulation did not show this upregulation. Serum stimulated phosphoinositide 3-kinase (PI 3-kinase) activity appeared to be comparable between +/+ and -/- cells. Moreover, protein kinase B, but not mitogen activated protein kinase activity, was also potentiated in SHIP2 deficient cells stimulated by serum. The upregulation of protein kinase B activity in serum stimulated cells was totally reversed in the presence of the PI 3-kinase inhibitor LY-294002, in both +/+ and -/- cells. Altogether, these data establish a link between SHIP2 and the acute control of PtdIns(3,4,5)P(3) levels in intact cells.

  19. Patogénesis de Listeria monocytogenes, microorganismo zoonotico emergente

    Directory of Open Access Journals (Sweden)

    Kirvis Torres

    2005-05-01

    Full Text Available Listeria monocytogenes además de ser un paradigma para la investigación inmunológica se ha convertidoen sistema modelo apropiado para el análisis de los mecanismos moleculares del parasitismo intracelularde otras bacterias. Investigadores en el área de la inmunología se interesaron en este microorganismocuando se reconoció el riesgo que representaba para la salud pública y la seguridad en la industria dealimentos. Desde mediados de los años 80’s se ha investigado la biología molecular de los marcadores devirulencia de este microorganismo, la biología celular de las interacciones de los marcadores de virulenciacon los receptores de la célula hospedero, el citoesqueleto, las vías de transducción de señales y losmecanismos de inmunidad mediada por células del hospedero. El propósito de esta revisión es describiralgunas características taxonómicas y filogenéticas de Listeria monocytogenes , la incidencia humana yanimal de varios serotipos, la fisiopatología de la infección , modelos animales y de cultivo celular utilizadospara estudios de virulencia, las poblaciones de riesgo, manifestaciones clínicas de listeriosis humana yanimal, el tratamiento, la organización genética y evolución de los determinantes de virulencia, losmecanismos empleados para interactuar con la célula hospedera, y los mecanismos para escapar de losprocesos de muerte celular y pasar de una célula infectada a otra. La información recopilada resulta degran importancia para el personal de salud, industria, consumidores y población de riesgo; razón por lacual Listeria monocytogenes es un patógeno que representa una amenaza para la salud pública mundial.

  20. Control of Listeria monocytogenes in food production plants

    Directory of Open Access Journals (Sweden)

    Dimitrijević Mirjana

    2008-01-01

    Full Text Available L. monocytogenes has been established in different plants for the production of food, including dairy plants, abattoirs, plants for the processing of fish, as well as those for the production of ready-to-eat (RTE food and this fact is being considered as the primary mechanism of food contamination with this bacteria. There is also the factor of numerous and diverse contaminated production equipment, because it has certain parts that are inaccessible for the necessary cleaning and disinfection. The temperature, position, as well as the material of the work surface are also linked to the contamination of plants with this bacteria. Investigations carried out so far have helped toward the better understanding of the manner and time of contamination of food items in the course of the production process, but there are still unresolved problems, including most certainly the biggest one - the adherence of bacteria and the creation of a biofilm, when the bacteria is in that condition more resistant to so-called stress factors which are usually used in the food industry for the purpose of decontamination of the surfaces with which foods come into contact. The control of L. monocytogenes in food production plants is possible primarily by using an integrated programme, compatible with the systems Hazard Analysis Critical Control Point (HACCP and Good Hygiene Practice (GHP, necessary in the production of food that is safe for the consumer. Essentially, the control measures that can contribute to reducing the incidence of findings of L.monocytogenes in the finished product, as well as the reducing of the level of contamination with this bacteria are linked, on the one hand, with hygiene procedures in the production process, and, on the other, with the applied technological procedures.

  1. Combination of endolysins and high pressure to inactivate Listeria monocytogenes.

    Science.gov (United States)

    van Nassau, Tomas J; Lenz, Christian A; Scherzinger, Anna S; Vogel, Rudi F

    2017-12-01

    Outbreaks of listeriosis are often related to the consumption of low-processed ready-to-eat food products (e.g. soft cheeses or smoked fish) contaminated with Listeria monocytogenes. Traditional preservation techniques, such as heat treatment, cannot eliminate Listeria from these products without strongly affecting the quality of the foods. We therefore investigated the use of endolysin (PlyP40, Ply511, or PlyP825) in combination with high hydrostatic pressure processing to kill L. monocytogenes in buffer. The results demonstrated a more than additive effect when both treatments were combined. For example, whereas 0.16 μg/mL PlyP825 or 300 MPa (1 min, 30 °C) applied individually reduced the cell count by 0.2 and 0.3 log cfu, respectively, a combined treatment resulted in a reduction of 5.5 log cfu. Similar results were obtained for the other endolysins combined with high pressure processing. We also showed that the synergistic inactivation of cells by endolysin and HHP is possible at a pressure level of only 200 MPa (2 min, 30 °C). Thus, the application of endolysins did not only substantially increase the bactericidal effect of high pressure, but it also enabled the inactivation of bacterial cells at much lower pressure levels. This shows the potential of using such combined processes for the inactivation of L. monocytogenes and food preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Compatibility study of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials

    International Nuclear Information System (INIS)

    Yan Qilong; Li Xiaojiang; Zhang Laying; Li Jizhen; Li Hongli; Liu Ziru

    2008-01-01

    The compatibility of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials of solid propellants was studied by using the pressure DSC method where, cyclotetramethylenetetranitroamine (HMX), cyclotrimethylenetrinitramine (RDX), 1,4-dinitropiperazine (DNP), 1.25/1-NC/NG mixture, lead 3-nitro-1,2,4-triazol-5-onate (NTO-Pb), aluminum powder (Al, particle size = 13.6 μm) and N-nitrodihydroxyethylaminedinitrate (DINA) were used as energetic components and polyethylene glycol (PEG), polyoxytetramethylene-co-oxyethylene (PET), addition product of hexamethylene diisocyanate and water (N-100), 2-nitrodianiline (2-NDPA), 1,3-dimethyl-1,3-diphenyl urea (C 2 ), carbon black (C.B.), aluminum oxide (Al 2 O 3 ), cupric 2,4-dihydroxy-benzoate (β-Cu), cupric adipate (AD-Cu) and lead phthalate (φ-Pb) were used as inert materials. It was concluded that the binary systems of TNAD with NTO-Pb, RDX, PET and Al powder are compatible, and systems of TNAD with DINA and HMX are slightly sensitive, and with 2-NDPA, φ-Pb, β-Cu, AD-Cu and Al 2 O 3 are sensitive, and with PEG, N-100, C 2 and C.B. are incompatible. The impact and friction sensitivity data of the TNAD and TNAD in combination with the other energetic materials under present study was also obtained, and there was no consequential affiliation between sensitivity and compatibility

  3. Evaluation of various tests for the diagnosis of soil contamination by 2,4,5-trichlorophenol (2,4,5-TCP)

    International Nuclear Information System (INIS)

    Bello, D.; Trasar-Cepeda, C.; Leiros, M.C.; Gil-Sotres, F.

    2008-01-01

    Soil response to contamination with 2,4,5-triclorophenol was studied to test the validity of the concept of Generic Reference Levels (GRL), the main criterion used to define soil contamination. Soil samples were artificially contaminated with doses between 0 and 5000 mg kg -1 of 2,4,5-triclorophenol, and analysed by various tests. Where possible, the response of soils to the contaminant was modelled by a sigmoidal dose-response curve in order to estimate the ED 50 values. The tests provided different responses, but only microbial biomass-C and dehydrogenase and urease activities demonstrated soil deterioration in response to contamination. The results suggest that the diagnosis of soil contamination has been greatly simplified in the legislation by the provision of a single figure for each compound, and that the GRL concept could perhaps be substituted by measurement of ED 50 values, which better reflect the alteration of a soil due to the presence of a xenobiotic substance. - The concentration of a toxic substance present in a soil cannot be considered as the only criteria to classify such soil as contaminated

  4. Pharmacological Potential and Synthetic Approaches of Imidazo[4,5-b]pyridine and Imidazo[4,5-c]pyridine Derivatives

    Directory of Open Access Journals (Sweden)

    Malwina Krause

    2017-03-01

    Full Text Available The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABAA receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines reported from the year 2000 to date, including structure–activity relationships.

  5. Pharmacological Potential and Synthetic Approaches of Imidazo[4,5-b]pyridine and Imidazo[4,5-c]pyridine Derivatives.

    Science.gov (United States)

    Krause, Malwina; Foks, Henryk; Gobis, Katarzyna

    2017-03-04

    The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABA A receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo[4,5- b ]pyridines and imidazo[4,5- c ]pyridines reported from the year 2000 to date, including structure-activity relationships.

  6. Listeria monocytogenes HAZARD MANAGEMENT IN A TYPICAL PRODUCT: THE CIAUSCOLO

    Directory of Open Access Journals (Sweden)

    S Fisichella

    2013-02-01

    Full Text Available The aim of the present study is to investigate operative procedures that allow to minimize Listeria monocytogenes (L. m. hazard in the main traditional sausage of the internal areas of Marche (Italy: the Ciauscolo, that has received the quality trademark PGI. It is made from lean cuts of well mature pork that is finely minced, adding fat which give the salami his characteristic softness and flavour. It is characterized by having a very little maturing period that determine high aw levels and, for this peculiarity, it allows L. m development.

  7. [Listeria monocytogenes nosocomial infection in the maternity ward].

    Science.gov (United States)

    Jean, D; Croize, J; Hirtz, P; Legeais, C; Pelloux, I; Favier, M; Mallaret, M R; Le Noc, P; Rambaud, P

    1991-01-01

    Nosocomial infection with Listeria monocytogenes 4b occurred in January 1990 in a maternity hospital in Grenoble. The 3 patients involved were born within a 24 hour-interval. The premature newborn responsible for contamination was asymptomatic. Two other newborns without any perinatal infectious risk presented with meningitis, one on the 5th day of life in the maternity hospital, the other one on the 11th day while already at home. The 3 strains of Listeria had the same serovar and lysovar. Epidemiologic investigations led to suspect a contamination in the delivery room and during the care of the children. Strict respect of hygiene orders is imperative to avoid nosocomial infections.

  8. Carbon dioxide and nisin act synergistically on Listeria monocytogenes

    DEFF Research Database (Denmark)

    Nilsson, Lilian; Chen, Y.H.; Chikindas, M.L.

    2000-01-01

    This paper examines the synergistic action of carbon dioxide and nisin on Listeria monocytogenes Scott A wild-type and nisin-resistant (Nis(r)) cells grown in broth at 4 degrees C. Carbon dioxide extended the lag phase and decreased the specific growth rate of both strains, but to a greater degree...... for cultures in CO2. This synergism between nisin and CO2 was examined mechanistically by following the leakage of carboxyfluorescein (CF) from listerial liposomes. Carbon dioxide enhanced nisin-induced CF leakage, indicating that the synergistic action of CO2 and nisin occurs at the cytoplasmic membrane...

  9. Genotoxic activity of 4,4',5'-trimethylazapsoralen on plasmid DNA.

    Science.gov (United States)

    Lagatolla, C; Dolzani, L; Granzotto, M; Monti-Bragadin, C

    1998-01-01

    The genotoxic activities of 8-methoxypsoralen (8-MOP) and 4,4',5'-trimethylazapsoralen (4,4',5'-TMAP) on plasmid DNA have been compared. In a previous work, 4,4',5'-TMAP, a methyl derivative of a psoralen isoster, had shown potential photochemotherapeutic activity. The mutagenic activity of mono- and bifunctional lesions caused by these compounds was evaluated both after UVA irradiation, which causes the formation of both kinds of lesions, and after a two-step irradiation procedure of the psoralen-plasmid DNA complex, which allowed monoadducts and interstrand crosslinks to be studied separately. Furthermore, we used a procedure that allowed us to evaluate both the mutagenic and recombinogenic activity of the two compounds. Results indicate that the most important difference between 8-MOP and 4,4',5'-TMAP consists in their mode of photoreaction with DNA rather than in their mutagenic potential. In fact, in all of the experimental procedures, 4,4',5'-TMAP shows a lower ability than 8-MOP to generate interstrand crosslinks. However, when comparable toxicity levels are reached, the two compounds show the same mutagenic potentiality.

  10. GERMINATION OF GRASSES DUE TO INOCULATION DIAZOTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    C. D. A. Moreira

    2014-07-01

    Full Text Available The germination of forage grasses suffers from numbness and a natural tendency to low quality. The use of microorganisms inoculated in seeds with the purpose of increasing and meet the demand of some nutrient has been shown to be efficient, but the role of the microorganism in germination and rate of force is still unknown. Therefore the goal as study was to evaluate the germination rate of seeds of three cultivars of Brachiaria brizantha CV. Marandu, b., b. brizantha CV. Xaraés and b. humidícola cv Tupi and a cultivar of millet, P. hybrid cv Massai depending on the bacterium Azospirillum brasilense diazotrofic inoculation (nitrogen-fixing. Germination test was used in seed dispersal to assess the effect of first count (VPC in the treatments with and without inoculation. It was done also conducted further tests of electrical conductivity, weight of thousand seeds and water content. The delineation used was randomized entirely (DIC and the statistical analysis carried out through the analysis of variance and comparison of means using the Tukey test, the 5% probability. Massai grass seeds have the highest rate of force of first count in both treatments. Inoculation of bacterium Azospirillum brasilense did not affect the values of force of first count on seeds of the cultivars Marandu, Xaraés, Tupi and Massai. The seeds of the massai have higher germination speed relative the other cultivars evaluated when inoculated.

  11. Key factors to inoculate Botrytis cinerea in tomato plants

    Directory of Open Access Journals (Sweden)

    Álefe Vitorino Borges

    2014-09-01

    Full Text Available Studies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness of gelatin regarding inoculum adhesion. Infection with an isolate from tomato plants that was previously inoculated into petioles and then re-isolated was successful. An isolate from strawberry plants was also aggressive, although less than that from tomato plants. Tomato plants close to flowering, at 65 days after sowing, and younger, middle and apical stem portions were more susceptible. There was positive correlation between lesion length and sporulation and between lesion length and broken stems. Lesion length and the percentage of sporulation sites were reduced by using a moist chamber and were not affected by adding gelatin to the inoculum suspension. This methodology has been adopted in studies of B. cinerea in tomato plants showing reproducible results. The obtained results may assist researchers who study the gray mold.

  12. Sunflower growth according to seed inoculation with endophytic bacteria

    Directory of Open Access Journals (Sweden)

    Juliana Fernandes dos Santos

    2014-06-01

    Full Text Available The sunflower crop has a great importance worldwide, due to the oil of excellent quality extracted from its seeds and in natura grains that are consumed in various ways. However, drought is one of the main environmental factors that limit its yield. An experiment was carried out under controlled greenhouse conditions, in a completely randomized experimental design, in order to determine the effect of endophytic bacteria inoculation (Bacillus sp. and Enterobacter cloacae on the growth and contents of nutrients and organic solutes, in sunflower leaves and roots under water deficit. Plant height, stem diameter, fresh and dry biomass of shoot and roots, as well as contents of N, P, K, soluble carbohydrates, free proline, free amino acids and soluble proteins, were determined at 35 days after the plant emergence. The water deficit reduced plant growth regardless inoculation. However, under optimum conditions of soil moisture, the combination of both endophytic bacteria increased the sunflower growth. The water deficit also increased the N and K contents in leaves, as well as the organic solutes content in shoots, especially in inoculated plants. These results suggest that the inoculation of endophytic bacteria may increase the capacity of drought stressed plants to perform the osmotic adjustment through a higher accumulation of organic solutes, when compared to plants not inoculated.

  13. Cross inoculation of anthracnose pathogens infecting various tropical fruits

    Science.gov (United States)

    Suparman; Rahmiyah, M.; Pujiastuti, Y.; Gunawan, B.; Arsi

    2018-01-01

    Anthracnose disease is very important disease of tropical fruits causing significant yield losses. The disease is caused by Colletotrichum spp. and infects almost all tropical fruit species, especially the succulent ones. Various species of Colletotrichum infect various tropical fruits and there are possibilities for cross inoculation to occur among tropical fruits which might cause severe infection. An experimental research was conducted to examine the effect of cross inoculation of anthracnose pathogen among papaya, eggplant, chili and common bean on the infection development and severity of the disease on each inoculated fruit species. Colletotrichum spp. were isolated from naturally infected papaya, eggplant, chili and common bean. Each fungal isolate was purified and identified to determine the species name. The spores of each isolate were then used to separately inoculate healthy and sterilized papaya, eggplant, chili and common bean. The results showed that cross infection developed on chili, eggplant and papaya but not on bean. Chili showed the highest susceptibility to all Colletotrichum isolates and significantly different from eggplant and papaya. The anthracnose pathogen isolated from common bean showed no pathogenicity to other hosts and might be used as cross protection inoculant to the disease in the other hosts.

  14. Listeria monocytogenes associated kerato-conjunctivitis in four horses in Norway.

    Science.gov (United States)

    Revold, Tobias; Abayneh, Takele; Brun-Hansen, Hege; Kleppe, Signe L; Ropstad, Ernst-Otto; Hellings, Robert A; Sørum, Henning

    2015-11-09

    Listeria monocytogenes has been reported to cause various infectious diseases in both humans and animals. More rarely, ocular infections have been reported. To our knowledge, only two cases of Listeria keratitis have been described in horses. We report kerato-conjunctivitis in four Norwegian horses associated with L. monocytogenes. Clinically, all cases were presented with recurrent unilateral kerato-conjunctivitis. L. monocytogenes bacteria were isolated from swab samples from all cases, and cytology carried out in 3 cases was indicative of L. monocytogenes infection. The present report describes the first known cases in which L. monocytogenes has been isolated from keratitic lesions in horses in Norway. A potential risk factor may be feeding of silage or haylage, but other sources of infection cannot be ruled out. The phenotypic features including antimicrobial susceptibility and serotype of the isolates are described. Laboratory detection of L. monocytogenes demands extra caution since only low numbers of bacteria were detected in the eye-swabs, probably due to the low volume of sample material and the intracellular niche of the bacterium. A general poor response to treatment in all these cases indicates that clinicians should pay extra attention to intensity and duration of treatment if L. monocytogenes is identified in connection with equine kerato-conjunctivitis.

  15. Listeria monocytogenes in Food-Processing Facilities, Food Contamination, and Human Listeriosis: The Brazilian Scenario.

    Science.gov (United States)

    Camargo, Anderson Carlos; Woodward, Joshua John; Call, Douglas Ruben; Nero, Luís Augusto

    2017-11-01

    Listeria monocytogenes is a foodborne pathogen that contaminates food-processing environments and persists within biofilms on equipment, utensils, floors, and drains, ultimately reaching final products by cross-contamination. This pathogen grows even under high salt conditions or refrigeration temperatures, remaining viable in various food products until the end of their shelf life. While the estimated incidence of listeriosis is lower than other enteric illnesses, infections caused by L. monocytogenes are more likely to lead to hospitalizations and fatalities. Despite the description of L. monocytogenes occurrence in Brazilian food-processing facilities and foods, there is a lack of consistent data regarding listeriosis cases and outbreaks directly associated with food consumption. Listeriosis requires rapid treatment with antibiotics and most drugs suitable for Gram-positive bacteria are effective against L. monocytogenes. Only a minority of clinical antibiotic-resistant L. monocytogenes strains have been described so far; whereas many strains recovered from food-processing facilities and foods exhibited resistance to antimicrobials not suitable against listeriosis. L. monocytogenes control in food industries is a challenge, demanding proper cleaning and application of sanitization procedures to eliminate this foodborne pathogen from the food-processing environment and ensure food safety. This review focuses on presenting the L. monocytogenes distribution in food-processing environment, food contamination, and control in the food industry, as well as the consequences of listeriosis to human health, providing a comparison of the current Brazilian situation with the international scenario.

  16. Prevalence and antimicrobial resistance of Listeria monocytogenes isolated in chicken slaughterhouses in Northern Greece.

    Science.gov (United States)

    Sakaridis, I; Soultos, N; Iossifidou, E; Papa, A; Ambrosiadis, I; Koidis, P

    2011-06-01

    This study was conducted to determine the prevalence and antimicrobial resistance of Listeria monocytogenes recovered from chicken carcasses in slaughterhouses in Northern Greece. A total of 100 poultry samples (300 carcasses) were examined for Listeria spp. The samples were neck skin taken from four different slaughterhouses in Northern Greece. Forty samples were also taken from the environment of the slaughterhouses. Identification of L. monocytogenes was carried out by PCR and fingerprinting of the isolates by random amplified polymorphic DNA. L. monocytogenes strains isolated from chicken carcasses and from the environment of the slaughterhouses were also examined for antibiotic resistance. Fifty-five isolates of L. monocytogenes were tested for susceptibility to 20 antibiotics using the disk diffusion method. Listeria spp. were present in 99 of the poultry samples tested (99%), and 38 yielded L monocytogenes (38%). L. monocytogenes was also isolated in 80% of samples from the environment of a certain slaughterhouse, while the other slaughterhouses were found to be contaminated only with Listeria spp. All isolates were resistant to nalidixic acid and oxolinic acid, the majority of them to clindamycin, and only a few to tetracycline and oxytetracycline, whereas they were found to be susceptible to all other antimicrobials. The results of this study demonstrate a high prevalence of L. monocytogenes contamination in chicken carcasses, and all isolates were found to be sensitive to the antimicrobials most commonly used to treat human listeriosis.

  17. Prevalence and characteristics of Listeria monocytogenes in bovine colostrum in Japan.

    Science.gov (United States)

    Hasegawa, Megumi; Iwabuchi, Eriko; Yamamoto, Shiori; Esaki, Hidetake; Kobayashi, Kazuhiko; Ito, Masahiko; Hirai, Katsuya

    2013-02-01

    This study was conducted to determine the prevalence and characteristics of Listeria monocytogenes in bovine colostrum in Japan. We collected bovine colostrum samples from 210 dams from 21 dairy farms in Hokkaido prefecture (Japan) between March and June 2009. L. monocytogenes was detected in samples from 6 (28.6%) of the 21 farms. Of the 210 samples, 16 (7.6%) were positive for L. monocytogenes. We recovered 80 L. monocytogenes isolates; 44 (55%) isolates were classified as serotype 1/2b and 36 (45%) were classified as serotype 4b. The isolates were susceptible to penicillin, ampicillin, amoxicillin, gentamicin, kanamycin, streptomycin, erythromycin, vancomycin, tetracycline, chloramphenicol, ciprofloxacin, and trimethoprim-sulfamethoxazole. Pulsed-field gel electrophoresis (PFGE) characterization of the 80 isolates revealed six PFGE types. Two PFGE types corresponded to human listeriosis cases. Most L. monocytogenes isolates possessed virulence-associated genes (actA, hly, iap, inlA, inlC, mpl, plcA, plcB, opuCA, prfA, and clpC). One PFGE type isolate possessed an epidemic clone II marker. Our findings suggest that isolates from bovine colostrum have the potential to cause human and animal listeriosis. This is the first study on the prevalence and characteristics of L. monocytogenes isolated from bovine colostrum obtained from dairy farms. Our results have important implications for improving public health and elucidating the epidemiology of L. monocytogenes in bovine colostrum.

  18. Relationship between Listeria monocytogenes and Listeria spp. in seafood processing plants.

    Science.gov (United States)

    Alali, Walid Q; Schaffner, Donald W

    2013-07-01

    The objective of this study was to evaluate the relationship between prevalence of Listeria monocytogenes as an outcome and Listeria spp. as an explanatory variable by food products, food contact surfaces, and nonfood contact surfaces in seafood processing plants by using peer-reviewed published data. Nine sets of prevalence data of L. monocytogenes and Listeria spp. were collected from published studies and used for the analyses. Based on our analysis, the relationship between L. monocytogenes prevalence and Listeria spp. prevalence in food products (incoming raw materials and finish products) was significant (P = 0.04) with (low) R² = 0.36. Furthermore, Listeria spp. were not a good indicator for L. monocytogenes when testing food contact surfaces (R² = 0.10). Listeria spp. were a good indicator for L. monocytogenes only on nonfood contact surfaces (R² = 0.90). On the other hand, the presence of Listeria spp. on food contact surfaces (R² = 0.002) and nonfood contact surfaces (R² = 0.03) was not a good indicator for L. monocytogenes presence in food products. In general, prevalence of Listeria spp. does not seem to be a good indicator for L. monocytogenes prevalence in seafood processing plants.

  19. Decreased plasma neurotrophin-4/5 levels in bipolar disorder patients in mania.

    Science.gov (United States)

    Barbosa, Izabela G; Morato, Isabela B; Huguet, Rodrigo B; Rocha, Fabio L; Machado-Vieira, Rodrigo; Teixeira, Antônio L

    2014-01-01

    To evaluate two poorly explored neurotrophins (NT), NT-3 and NT-4/5, in bipolar disorder (BD). Forty patients with type I BD (18 in remission and 22 in mania) and 25 healthy controls matched for age, gender, and educational attainment were enrolled in this study. All subjects were assessed by the Mini-International Neuropsychiatric Interview; the Young Mania Rating Scale and the Hamilton Depression Rating Scale were used to evaluate severity of symptoms in BD patients. Plasma levels of NT-3 and NT-4/5 were measured by enzyme-linked immunosorbent assay (ELISA). BD patients in mania presented decreased NT-4/5 plasma levels in comparison with controls (p neurotrophin dysfunction is associated with mood states in patients with BD.

  20. Control of segregation in squeeze cast Al-4.5Cu binary alloy

    Energy Technology Data Exchange (ETDEWEB)

    Durrant, G. [Oxford Univ. (United Kingdom). Dept. of Materials; Gallerneault, M. [Alcan International Ltd., Kingston, ON (Canada); Cantor, B. [Oxford Univ. (United Kingdom). Dept. of Materials

    1997-10-01

    The high pressure applied in squeeze casting allows Al alloys of wrought composition to be cast to near net-shape, although their long freezing range leads to the segregation of alloying elements. In this paper we present results on the squeeze casting and gravity casting of a model Al-4.5 wt%Cu alloy. Squeeze cast Al-4.5Cu has a normal segregation pattern with eutectic macrosegregates towards the centre of the billet, whereas gravity cast material has a typical inverse segregation pattern. Normal segregation in squeeze cast Al-4.5Cu is due to large temperature gradients during solidification. Segregation can be minimized by releasing the applied pressure during solidification to allow backflow of the interdendritic fluid, or by the addition of grain refiner to remove the large columnar dendritic growth structure. (orig.)

  1. A thiazepino[4,5-a]benzimidazole derivative hampers the RNA replication of Eurasian serotypes of foot-and-mouth disease virus.

    Science.gov (United States)

    Lefebvre, David J; De Vleeschauwer, Annebel R; Goris, Nesya; Van Borm, Steven; Chimirri, Alba; Monforte, Anna Maria; Valdazo-Gonzalez, Begona; King, Donald P; Neyts, Johan; De Clercq, Kris

    2014-12-12

    The stamping-out policy for the control of foot-and-mouth disease virus (FMDV) in countries that are free from FMD without vaccination has a dramatic socio-economic impact, huge animal welfare issues and may result in the loss of farm animal genetic resources. As an alternative to pre-emptive culling or emergency vaccination we further explore the possibility to use antiviral drugs in the event of an FMD outbreak. In the present study, we tested the in vitro cytotoxicity and anti-FMDV activity of 1,2,4,5-tetrahydro-[1,4]thiazepino[4,5-a]benzimidazole. The molecule was shown to inhibit the replication of reference strains of the Eurasian FMDV serotypes O, A, C and Asia but not the FMDV serotypes from the South African Territories (SAT) neither a related picornavirus, i.e. swine vesicular disease virus. The molecule can be added until 2h post inoculation in a 'single replication cycle experiment' without losing its antiviral activity. The genetic characterization of progressively selected resistant FMD viruses shows that the molecule presumably interacts with the non-structural 2C protein of FMDV. Further studies are required on the use of this molecule in vivo. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Prevalence and contamination patterns of Listeria monocytogenes in catfish processing environment and fresh fillets.

    Science.gov (United States)

    Chen, Bang-Yuan; Pyla, Rajkumar; Kim, Tae-Jo; Silva, Juan L; Jung, Yean-Sung

    2010-08-01

    Catfish skins, intestines, fresh fillets, processing surfaces at different production stages, chiller water and non-food contact surfaces were sampled for Listeria monocytogenes and other Listeria species. Among 315 samples, prevalence of L. monocytogenes, Listeria innocua and a group of Listeria seeligeri-Listeria welshimeri-Listeria ivanovii was 21.6, 13.0 and 29.5%, respectively. No Listeria grayi was detected in this survey. While no L. monocytogenes strains were isolated from catfish skins and intestines, the strains were found with a frequency of 76.7% in chilled fresh catfish fillets and 43.3% in unchilled fillets. L. monocytogenes and Listeria spp. were also detected in fish contact surfaces such as deheading machine, trimming board, chiller water, conveyor belts at different stages, and fillet weighing table. Among L. monocytogenes, 1/2b (47.0%), 3b (16.0%) and 4c (14%) were the predominant serotypes isolated, whereas 4b, 4e, 1/2c and 1/2a were detected at much lower frequencies. Genotype analyses of L. monocytogenes isolates using serotyping, pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed that chiller water represented an important contamination source of L. monocytogenes in the chilled catfish fillets of two processing facilities, whereas fillet weighing table significantly contributed to the catfish fillet contamination of the third facility. This study suggests that L. monocytogenes contamination in the processed catfish fillets originates from the processing environment, rather than directly from catfish. Results from this study can aid the catfish industry to develop a plant-specific proper cleaning and sanitation procedure for equipment and the processing environment designed to specifically target L. monocytogenes contamination. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Inducing Resistance to Conspiracy Theory Propaganda: Testing Inoculation and Metainoculation Strategies

    Science.gov (United States)

    Banas, John A.; Miller, Gregory

    2013-01-01

    This investigation examined the boundaries of inoculation theory by examining how inoculation can be applied to conspiracy theory propaganda as well as inoculation itself (called metainoculation). A 3-phase experiment with 312 participants compared 3 main groups: no-treatment control, inoculation, and metainoculation. Research questions explored…

  4. Rhenium(5) and molybdenum(5) complexes with 4',4(5)-divaleryldibenzo-18-crown-6

    International Nuclear Information System (INIS)

    Ashurova, N.Kh.; Yakubov, K.G.; Tashmukhamedova, A.K.; Basitova, S.M.

    1993-01-01

    Methods for synthesizing oxohalide complexes of rhenium and molybdenum with +5 oxidation degree with 4',4 (5) -divaleryldibenzo-18-crown-6 were developed. Content and composition of prepared compounds were investigated by the methods of element analysis, crystal optics, conductometry, IR spectroscopy in the near and far regions, thermogravimetry. Oxidation degree of the complex-forming metal was determined. It was established that composition of the compounds coressponded to the general formula MOLX · H 2 O, where M - Re, Mo; L -4',4 (5) -divaleryldibenzo-18-crown-6; X -Cl - , Br -

  5. Research On C4.5 As One Of The Inductive Learning Techniques

    OpenAIRE

    Yıldırım, Savaş

    2003-01-01

    The thesis in hand deals with C4.5 (Decision Tree Construction Algorithm) as one of the most significant techniques of machine learning, and how it differs from its older version ID3. With this aim in mind, not only the approaches provided by C4.5 but also other approaches are examined. The decision tree algorithms are useful in a variety of spheres from defense to medicine or economics; and bear a vital importance for decision support systems in these areas. Written by Quinlan in 1993 in C p...

  6. Analisis Kinerja Algoritma C4.5 Pada Sistem Pendukung Keputusan Penentuan Jenis Pelatihan

    OpenAIRE

    Oktavia, Chaulina Alfianti; Rahmadwati, Rahmadwati; Santoso, Purnomo Budi

    2015-01-01

    - This study describes the application of the algorithm C4.5 on decision support systems to support trainees in PPTIK STIKI Malang in choosing the appropriate type of training. Decision support system based on several criteria derived from the data filled out by participants prior to register as a participant. Further analysis using an algorithm that is used to form a C4.5 decision tree. The decision tree is a method of classification and prediction that represent rules. the rule is then deve...

  7. In vivo and in vitro dermal penetration of 2,4,5,2',4', 5'-hexachlorobiphenyl in young and adult rats

    International Nuclear Information System (INIS)

    Shah, P.V.; Sumler, M.R.; Fisher, H.L.; Hall, L.L.

    1989-01-01

    Penetration of 2,4,5,2',4',5'-[ 14 C]hexachlorobiphenyl (HCB) through skin of young (33 days) and adult (82 days) female Fischer 344 rats was determined in vivo and by two in vitro methods. In vivo dermal penetration at 120 hr was 45% in young and 43% in adults. At 72 hr in vivo dermal penetration was 35% in young and 26% in adults compared to 1.5% for young and 1.0% for adult as measured with a continuous flow in vitro system and 2.9% for young and 1.9% for adults as measured with a static in vitro system. Most of the dermally absorbed HCB remained in the body as only 4.9 and 2.6% of that absorbed was excreted by young and adult rats, respectively, at the end of 120 hr. Significant differences in dermal penetration and kinetics of HCB between young and adult female rats were observed. The elimination of ECB-derived material was approximately six times higher in feces than in urine. A physiological pharmacokinetic model was fitted to the organ and tissue radioactivity distribution data. Parameters in the model determined from dermal dosing of female Fischer 344 rats were in reasonable agreement with those reported in the literature for adult male Sprague-Dawley rats (iv dose). The rate constant for dermal penetration was 0.83 x 10 -4 min -1 for adults and 0.96 x 10 -4 min -1 for young. The delay or lag time parameter for dermal penetration was 4.4 hr in adults and 1.1 hr in young

  8. Effect of Inoculant Alloy Selection and Particle Size on Efficiency of Isomorphic Inoculation of Ti-Al.

    Science.gov (United States)

    Kennedy, J R; Rouat, B; Daloz, D; Bouzy, E; Zollinger, J

    2018-04-25

    The process of isomorphic inoculation relies on precise selection of inoculant alloys for a given system. Three alloys, Ti-10Al-25Nb, Ti-25Al-10Ta, and Ti-47Ta (at %) were selected as potential isomorphic inoculants for a Ti-46Al alloy. The binary Ti-Ta alloy selected was found to be ineffective as an inoculant due to its large density difference with the melt, causing the particles to settle. Both ternary alloys were successfully implemented as isomorphic inoculants that decreased the equiaxed grain size and increased the equiaxed fraction in their ingots. The degree of grain refinement obtained was found to be dependent on the number of particles introduced to the melt. Also, more new grains were formed than particles added to the melt. The grains/particle efficiency varied from greater than one to nearly twenty as the size of the particle increased. This is attributed to the breaking up of particles into smaller particles by dissolution in the melt. For a given particle size, Ti-Al-Ta and Ti-Al-Nb particles were found to have a roughly similar grain/particle efficiency.

  9. Experimental inoculation of equine coronavirus into Japanese draft horses.

    Science.gov (United States)

    Nemoto, Manabu; Oue, Yasuhiro; Morita, Yoshinori; Kanno, Toru; Kinoshita, Yuta; Niwa, Hidekazu; Ueno, Takanori; Katayama, Yoshinari; Bannai, Hiroshi; Tsujimura, Koji; Yamanaka, Takashi; Kondo, Takashi

    2014-12-01

    Recently, outbreaks associated with equine coronavirus (ECoV) have occurred in Japan and the United States. While ECoV is likely to be pathogenic to horses, it has not been shown that experimental inoculation of horses with ECoV produces clinical signs of disease. In this study, we inoculated three Japanese draft horses with an ECoV-positive diarrheic fecal sample to confirm infection after inoculation and to investigate the clinical course and virus shedding patterns of ECoV. Virus neutralization tests showed that all three horses became infected with ECoV. Two of the three horses developed clinical signs similar to those observed during ECoV outbreaks, including fever, anorexia, and gastrointestinal dysfunction. All horses excreted a large amount of virus into their feces for more than 9 days after inoculation regardless of the presence or absence of clinical signs, which suggests that feces are an important source of ECoV infection. ECoV was also detected in nasal swabs from all horses, suggesting that respiratory transmission of ECoV may occur. Both symptomatic horses developed viremia, while the asymptomatic horse did not. White blood cell counts and serum amyloid A concentrations changed relative to the clinical condition of the inoculated horses; these may be useful markers for monitoring the clinical status of horses infected with ECoV. This is the first report of induction of clinical signs of ECoV infection in horses by experimental inoculation. These clinical and virological findings should aid further investigation of the pathogenesis of ECoV.

  10. Listeria monocytogenes contamination in dairy plants: evaluation of Listeria monocytogenes environmental contamination in two cheese-making plants using sheeps milk

    Directory of Open Access Journals (Sweden)

    Michela Ibba

    2013-09-01

    Full Text Available Listeria monocytogenes harbouring niches established in the processing plant support post-process contamination of dairy products made from pasteurised or thermised milk. The present study investigated L. monocytogenes environmental contamination in two sheep’s milk cheese-making plants. Persistence of contamination in the area at higher risk was also investigated. During a one-year survey 7 samplings were carried out in each dairy plant, along the production lines of Pecorino Romano and ricotta salata cheese. A total of 613 environmental samples collected from food contact and non-food contact surfaces were analysed according to ISO 11290-1:2005 standard method. Identification of the isolated strains was carried out by polymerase chain reaction. L. monocytogenes prevalence was 23.2% in dairy A and 13.1% in dairy B, respectively. The higher prevalence rate was found in the following areas: salting, products washing, packaging, ricotta salata storage and Pecorino Romano ripening rooms. L. monocytogenes was never found in the cheese-making area. The probability of observing samples positive for the presence of L. monocytogenes was asso- ciated with dairy plant, sampling area and the period of cheese-making (P<0.001. The greater persistence of contamination over time was observed in the washing, salting, and Pecorino Romano ripening areas. The control of persistent environmental contamination relies on the identification of L. monocytogenes niches within the processing environment and the prevention of harborage sites formation. The importance of strict cleaning and sanitising procedure in controlling L. monocytogenes environmental contamination is confirmed by the lower level of contamination observed after these procedures were correctly implemented.

  11. Prevalence and quantification of Listeria monocytogenes in chicken offal at the retail level in Malaysia.

    Science.gov (United States)

    Kuan, C H; Goh, S G; Loo, Y Y; Chang, W S; Lye, Y L; Puspanadan, S; Tang, J Y H; Nakaguchi, Y; Nishibuchi, M; Mahyudin, N A; Radu, S

    2013-06-01

    A total of 216 chicken offal samples (chicken liver = 72; chicken heart = 72; chicken gizzard = 72) from wet markets and hypermarkets in Selangor, Malaysia, were examined for the presence and density of Listeria monocytogenes by using a combination of the most probable number and PCR method. The prevalence of L. monocytogenes in 216 chicken offal samples examined was 26.39%, and among the positive samples, the chicken gizzard showed the highest percentage at 33.33% compared with chicken liver (25.00%) and chicken heart (20.83%). The microbial load of L. monocytogenes in chicken offal samples ranged from Malaysia.

  12. Flagellar motility is critical for Listeria monocytogenes biofilm formation.

    Science.gov (United States)

    Lemon, Katherine P; Higgins, Darren E; Kolter, Roberto

    2007-06-01

    The food-borne pathogen Listeria monocytogenes attaches to environmental surfaces and forms biofilms that can be a source of food contamination, yet little is known about the molecular mechanisms of its biofilm development. We observed that nonmotile mutants were defective in biofilm formation. To investigate how flagella might function during biofilm formation, we compared the wild type with flagellum-minus and paralyzed-flagellum mutants. Both nonmotile mutants were defective in biofilm development, presumably at an early stage, as they were also defective in attachment to glass during the first few hours of surface exposure. This attachment defect could be significantly overcome by providing exogenous movement toward the surface via centrifugation. However, this centrifugation did not restore mature biofilm formation. Our results indicate that it is flagellum-mediated motility that is critical for both initial surface attachment and subsequent biofilm formation. Also, any role for L. monocytogenes flagella as adhesins on abiotic surfaces appears to be either minimal or motility dependent under the conditions we examined.

  13. Enterocin CRL35 inhibits Listeria monocytogenes in a murine model.

    Science.gov (United States)

    Salvucci, Emiliano; Saavedra, Lucila; Hebert, Elvira Maria; Haro, Cecilia; Sesma, Fernando

    2012-01-01

    Listeria monocytogenes is a foodborne pathogen causative of opportunistic infections. Listeriosis is associated with severe infections in pregnant women causing abortion or neonatal listeriosis. An alternative to antibiotics are safe novel bacteriocins peptides such as enterocin CRL35 with strong antilisterial activity produced by Enterococcus mundtii CRL35. In the present paper, our goal is to study the effectiveness of this peptide and the producer strain in a murine model of pregnancy-associated listeriosis. A single dose of 5×10(9) colony-forming unit of L. monocytogenes FBUNT (Faculty of Biochemistry-University of Tucumán) resulted in translocation of pathogen to liver and spleen of BALB/c pregnant mice. The maximum level of Listeria was observed on day 3 postinfection. Interestingly, the intragastric administration of enterocin CRL35 significantly reduced the translocation of the pathogen to vital organs. On the other hand, the preadministration of E. mundtii CRL35 slightly inhibited this translocation. Listeria infection caused a significant increase in polymorphonuclear leukocytes at day 3 postinfection compared to the noninfected group. This value was reduced after the administration of enterocin CRL35. No significant changes were observed in either white blood cells or lymphocytes counts. Based on the data presented in the present work enterocin CRL35 would be a promising alternative for the prevention of Listeria infections.

  14. ASSESSMENT OF ACTION OF DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES BIOFILMS

    Directory of Open Access Journals (Sweden)

    T. K. CABEÇA

    2008-12-01

    Full Text Available

    The purpose of this study was to assess the action of various disinfectants used in food industry against biofilm cells of Listeria monocytogenes formed on stainless steel surfaces during 24, 72 and 120 hours. Numbers of viable biofilm cells decreased after treatment with all the tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against the biofilm cells, while biguanide and iodine were the least. Scanning electron microscopy observations demonstrated attached cells on stainless steel surfaces after treatment with all the disinfectants. These observations showed that microorganisms were not completely removed from stainless steel surfaces after treatment with the disinfectants, however, the attachment did not means the viability of remaining cells. The biofilm age in hours (24, 72 and 120 had no apparent influence on resistance of microbiological cells to the disinfectants under study. In conclusion biofilm cells of L. monocytogenes can withstand disinfectants action.

  15. Identification of Listeria monocytogenes on Green Mussels and Cockle Shell

    Directory of Open Access Journals (Sweden)

    Winiati Puji Rahayu

    2017-02-01

    Full Text Available AbstractGreen mussel (Perna viridis and cockle shell (Anadara granosa are one of many sources of animal protein which is many cultivated in Indonesia because their price is relatively affordable. This study was conducted to identify the presence of Listeria monocytogenes in 27 samples of green mussels and 3 samples of cockle shells using real-time Polymerase Chain Reaction (real-time PCR and biochemical methods. The target gene for amplification in real-time PCR was an hlyA gene because this gene was a determinant of virulence genes that produce listeriolysin O. Primers used in this study were forward primer DG69 (GTG CCG GGT AAA AGA CCA TA and reverse primer DG74 (CGC CAC TGA GAT ACT AT and fluorescence signals indicator using SYBR Green I. The results of analysis using real-time PCR were negative Listeria monocytogenes in all samples, while using biochemical methods there was one of 30 samples contaminated by Listeria welshimeri.

  16. Effect of actinobacteria agent inoculation methods on cellulose degradation during composting based on redundancy analysis.

    Science.gov (United States)

    Zhao, Yue; Lu, Qian; Wei, Yuquan; Cui, Hongyang; Zhang, Xu; Wang, Xueqin; Shan, Si; Wei, Zimin

    2016-11-01

    In this study, actinobacteria agent including Streptomyces sp. and Micromonospora sp. were inoculated during chicken manure composting by different inoculation methods. The effect of different treatments on cellulose degradation and the relationship between inoculants and indigenous actinobacteria were investigated during composting. The results showed that inoculation in different stages of composting all improved the actinobacteria community diversity particularly in the cooling stage of composting (M3). Moreover, inoculation could distinctly accelerate the degradation of organic matters (OM) especially celluloses. Redundancy analysis indicated that the correlation between indigenous actinobacteria and degradation of OM and cellulose were regulated by inoculants and there were significant differences between different inoculation methods. Furthermore, synergy between indigenous actinobacteria and inoculants for degradation of OM and cellulose in M3 was better than other treatments. Conclusively, we suggested an inoculation method to regulate the indigenous actinobacteria based on the relationship between inoculants and indigenous actinobacteria and degradation content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. 3,4,5-Tri-dodecyloxybenzoic acid: optimisation and scale-up of the synthesis

    NARCIS (Netherlands)

    Hersmis, M.C.; Spiering, A.J.H.; Waterval, R.J.M.; Meuldijk, J.; Vekemans, J.A.J.M.; Hulshof, L.A.

    2001-01-01

    The synthesis of tris-O-dodecyl-gallic acid [3,4,5-tris(dodecyloxy)benzoic acid] - a versatile building block for org. liq. cryst. materials - has been selected for fine chem. scale-up. A large-scale procedure of the alkylation of Me gallate with dodecyl bromide was optimized with exptl. design

  18. Fabrication and properties of strip casting 4.5 wt% Si steel thin sheet

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Guoqing, E-mail: gz854@uowmail.edu.au [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Zhang, Xiaoming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Zhao, Jingwei [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Wang, Yuqian [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Yan, Yi [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Li, Chengang; Cao, Guangming [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Jiang, Zhengyi [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia)

    2017-02-15

    Three 4.5 wt% Si steel thin sheets with different thicknesses were efficiently fabricated by twin-roll strip casting, warm rolling and cold rolling followed by final annealing. A comprehensive investigation from the workability of the as-cast strip to the magnetic property of the produces was performed to illustrate the superiority of the new materials. The results show that the as-cast strip, which has a much lower Vickers hardness than that of the 6.5 wt% Si steel, is suitable for rolling processing. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies confirm that no ordering phase exists in the as-cast strip. The cold-rolled thin sheets exhibit good surface quality without edge cracks. Furthermore, all the three 4.5 wt% Si steel thin sheets possess relative strong <100>//ND texture and present high magnetic inductions and low iron losses after finial annealing. - Highlights: • 4.5 wt% Si as-cast sheet with excellent workability was produced by strip casting. • Three 4.5 wt% Si thin sheets were effectively fabricated by warm and cold rolling. • The microstructure and macro-texture of the thin sheets were elucidated. • High magnetic inductions and low iron losses were achieved simultaneously.

  19. Tannic acid Catalyzed an Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole

    Directory of Open Access Journals (Sweden)

    Shitole Nana Vikram

    2013-05-01

    Full Text Available Tannic acid (C76H52O46 has been found to be an efficient catalyst for one-pot synthesis of 2,4,5-triaryl substituted imidazoles by the reaction of an arylaldehyde, benzyl/benzoin and an ammonium acetate. The short reaction time and excellent yields making this protocol practical and economically attractive.

  20. 2,4,5-trihydroxy-3-methylacetophenone: A cellulosic chromophore as a case study of aromaticity

    Science.gov (United States)

    Nele Sophie Zwirchmayr; Thomas Elder; Markus Bacher; Andreas Hofinger-Horvath; Paul Kosma; Thomas. Rosenau

    2017-01-01

    The title compound (2,4,5-trihydroxy-3-methylacetophenone, 1) was isolated as chromophore from aged cellulosic pulps. The peculiar feature of the compound is its weak aromatic system that can be converted into nonaromatic (quinoid or cyclic aliphatic) tautomers, depending on the conditions and reaction partners. In alkaline media, the participation of quinoid canonic...

  1. Seasonality in the coastal lowlands of Kenya; Pt. 4/5 : Food consumption and anthropometry

    NARCIS (Netherlands)

    Foeken, D.W.J.; Klaver, W.; Niemeijer, R.

    1991-01-01

    This is Part 4/5 of a series concerned with seasonality in the coastal lowlands of Kenya. Household surveys were carried out in six locations in Kwale and Kilifi Districts in 1985-1987. The present report deals with food consumption and the nutritional condition of the study population. Results show

  2. On the Stability of L4,5 in the Relativistic R3BP with Radiating ...

    Indian Academy of Sciences (India)

    Abstract. This paper discusses the motion of a test particle in the neigh- bourhood of the triangular points L4,5 by considering the less massive primary (secondary) as a source of radiation in the framework of the relativistic restricted three-body problem (R3BP). It is found that the positions and stability of the triangular point ...

  3. PENERAPAN ALGORITMA C4.5 UNTUK PREDIKSI PENGGUNAAN JENIS KONTRASEPSI BERBASIS WEB

    Directory of Open Access Journals (Sweden)

    Rusda Wajhillah

    2017-09-01

    Keluarga Berencana (KB merupakan suatu program pemerintah yang dirancang untuk menyeimbangkan antara kebutuhan dan jumlah penduduk dengan menggunakan alat kontrasepsi. Kurangnya pengetahuan tentang kontrasepsi menyebabkan tidak sedikit akseptor lebih memilih menggunakan kontrasepsi berdasarkan coba-coba atau bahkan mengikuti saran dari orang lain yang kurang paham terhadap alat kontrasepsi. Oleh sebab itu, diperlukan adanya tindakan/penanganan khusus untuk mempermudah para akseptor dalam memilih kontrasepsi yang efektif dan sesuai dengan kondisi tubuhnya. Algoritma C4.5 yaitu metode pohon keputusan mengubah fakta yang sangat besar menjadi pohon keputusan yang merepresentasikan aturan. Aturan dapat dengan mudah dipahami dengan bahasa alami.Untuk itu, dalam penelitian ini akan dilakukan analisa data penggunaan jenis kontrasepsi menggunakan klasifikasi data mining yakni algoritma C4.5 dengan menggunakan beberapa parameter diantaranya usia, jumlah anak, tekanan darah dan riwayat penyakit yang akan diaplikasikan dalam bentuk web guna mempermudah para akseptor dalam mendapatkan nilai informasi yang lebih cepat dan fleksibel. Dari 130 jumlah kasus yang terdiri dari 104 kasus akseptor pengguna kontrasepsi hormonal dan 26 kasus pengguna kontrasepsi non hormonal yang didapat dari Posyandu Desa Nyangkowek Kecamatan Cicurug, maka didapatkan 14 rule yang dihasilkan dari pohon keputusan algoritma C4.5 dengan jumlah class non hormonal sebanyak 8 rule dan jumlah class hormonal sebanyak 6 rule serta dievaluasi dengan pengujian Cross Validation yangmenghasilkan tingkat akurasi sebesar 85,38%, sehingga dapat disimpulkan bahwa penelitian ini dapat membantu para akseptor KB dalam memilih jenis kontrasepsi yang efektif. Kata Kunci: Akseptor, Algoritma C4.5, Kontrasepsi, Sistem Pakar

  4. Novel synthesis of 4(5)-monosubstituted imidazoles via cycloaddition of tosylmethyl isocyanide to aldimines

    NARCIS (Netherlands)

    ten Have, Ronald; Huisman, M; Meetsma, A; van Leusen, A.M.

    1997-01-01

    4(5)-Monosubstituted imidazoles (9) have been prepared via base-induced cycloaddition of tosylmethyl isocyanide (TosMIC) to N-(dimethylsulfamoyl)aldimines (2) or N-tosylaldimines (3). In the first case, N-(dimethylsulfamoyl)imidazoles 8 are the initial reaction products, from which the

  5. Optimization of C4.5 algorithm-based particle swarm optimization for breast cancer diagnosis

    Science.gov (United States)

    Muslim, M. A.; Rukmana, S. H.; Sugiharti, E.; Prasetiyo, B.; Alimah, S.

    2018-03-01

    Data mining has become a basic methodology for computational applications in the field of medical domains. Data mining can be applied in the health field such as for diagnosis of breast cancer, heart disease, diabetes and others. Breast cancer is most common in women, with more than one million cases and nearly 600,000 deaths occurring worldwide each year. The most effective way to reduce breast cancer deaths was by early diagnosis. This study aims to determine the level of breast cancer diagnosis. This research data uses Wisconsin Breast Cancer dataset (WBC) from UCI machine learning. The method used in this research is the algorithm C4.5 and Particle Swarm Optimization (PSO) as a feature option and to optimize the algorithm. C4.5. Ten-fold cross-validation is used as a validation method and a confusion matrix. The result of this research is C4.5 algorithm. The particle swarm optimization C4.5 algorithm has increased by 0.88%.

  6. Drie nuwe verklaringsopsies in die Jakobusbrief (Jak 2:1; 4:5; 5:6 ...

    African Journals Online (AJOL)

    New options in the understanding of the Epistle of James (Js 2:1; 4:5; 5:6) New methods of interpretation occasionally lead to new options in the understanding of texts. In the case of the Epistle of James, the interpretation has until recently stood under the spell of the 'comparative' method of Dibelius. Greater emphasis on ...

  7. Health bill and MDGS 4, 5, & 6 | Daru | Tropical Journal of Obstetrics ...

    African Journals Online (AJOL)

    Tropical Journal of Obstetrics and Gynaecology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 30, No 2 (2013) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Health bill and MDGS 4, 5, & 6. PH Daru ...

  8. Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid by metal-oxide-coated Ti electrodes.

    Science.gov (United States)

    Maharana, Dusmant; Xu, Zesheng; Niu, Junfeng; Rao, Neti Nageswara

    2015-10-01

    Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) over metal-oxide-coated Ti anodes, i.e., Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2, was examined. The degradation efficiency of over 90% was attained at 20 min at different initial concentrations (0.5-20 mg L(-1)) and initial pH values (3.1-11.2). The degradation efficiencies of 2,4,5-T on Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2 anodes were higher than 99.9%, 97.2% and 91.5% at 30 min, respectively, and the respective total organic carbon removal ratios were 65.7%, 54.6% and 37.2%. The electrochemical degradation of 2,4,5-T in aqueous solution followed pseudo-first-order kinetics. The compounds, i.e., 2,5-dichlorohydroquinone and 2,5-dihydroxy-p-benzoquinone, have been identified as the main aromatic intermediates by liquid chromatography-mass spectrometry. The results showed that the energy efficiencies of 2,4,5-T (20 mg L(-1)) degradation with Ti/SnO2-Sb/Ce-PbO2 anode at the optimal current densities from 2 to 16 mA cm(-2) ranged from 8.21 to 18.73 kWh m(-3). Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. The disposition and metabolism of durene (1,2,4,5-tetramethylbenzene) in rats

    International Nuclear Information System (INIS)

    Ligocka, D.; Sapota, A.; Rydzynski, K.

    2001-01-01

    The organ and tissue distribution, excretion and metabolism of [ 3 H]1,2,4,5-tetramethylbenzene ([ 3 H]durene) in male Wistar albino rats were investigated following a single i.p. administration (40 mg/kg) and within 9 days after five daily repeated administrations. Urine proved to be the main route of tritium excretion. Within the first 24 h after a single administration 69% of the radioactivity was excreted in the urine and only 9% in the feces. The highest level of tritium binding was found in the fat tissue, liver, kidneys and adrenal glands. The accumulation of tritium in the plasma proceeded with a kinetic constant of 0.49 h -1 , whereas the half-life of radioactivity decayamounted to about 6.3 h. In erythrocytes, the tritium level was found to be about three times lower than in blood plasma. The total amount eliminated during the 9 days following repeated administration was about 94% of the five doses given. The highest level of tritium was found in fat tissue and adrenal glands, followed by the liver, kidneys, sciatic nerve and muscle. A gradual decline in tritium levels was observed during the following 4 days in most tissues to reach about 2% of the dose given. The main urinary metabolites resulting from the administration of durene were 2,4,5-trimethylbenzyl alcohol (about 22%), 4,5-dimethyl-1,2-benzdialdehyde (about 19%), 2,4,5-trimethylbenzaldehyde (about 19%) and 2,4,5-trimethylbenzoic acid (about 16%). The oxygen-containing metabolites accounted for almost 80%, whereas sulphur-containing metabolites accounted for approximately 10% of the products of biotransformation. In conclusion, most of the durene administered has a relatively rapid turnover rate, with minor levels retained in the tissues for longer time periods. (orig.)

  10. Determination of indium(III) with 3,4,5,6-tetrachlorogallein and cetylpyridinium chloride

    International Nuclear Information System (INIS)

    Mori, Itsuo; Fujita, Yoshikazu; Ida, Masako; Enoki, Takehisa

    1976-01-01

    Rapid and highly sensitive methods have been developed for the spectrophotometric and titrimetric determination of indium(III) with 3,4,5,6-tetrachlorogallein(3,4,5,6-T. Cl, Gal.) and cetylpyridinium chloride(CPC) in aqueous solutions of pH 4.2--5.2. The absorbance of the indium(III)-3,4,5,6-T. Cl. Gal. complex at 620 nm and the color change (pure blue - weak violetish red) were used to indicate the end point in the EDTA titration. The calibration curve for the spectrophotometry was linear in the range 0--45.0 μg In(III)/10 ml. According to Sandell's expression, the sensitivity was 0.0032 μg In(III)/cm 2 for an absorbance of 0.001. To the solution containing less than 45.0 μg of indium(III), 2.0 ml of 1.0x10 -2 M CPC solution, 3.0 ml of Walpole buffer solution(pH 4.4; acetic acid-sodium acetate), and 2.0 ml of 1.0x10 -3 M 3,4,5,6-T.Cl.Gal. methanol solution were added and the volume was made up to 10.0 ml with water. The solution was kept at (20--25) 0 C for 30 minutes and then the absorbance was measured at 620 nm against the reagent blank. The mole ratio of indium(III), 3,4,5,6-T.Cl.Gal. and CPC in the complex was estimated to be 1 : 2 : 2 by the continuous variation and the mole ratio methods. (auth.)

  11. A Radiographic Measurement of the Anterior Epidural Space at L4-5 Disc Level.

    Science.gov (United States)

    Xu, Rui-Sheng; Wu, Jie-Shi; Lu, Hai-Dan; Zhu, Hao-Gang; Li, Xia; Dong, Jian; Yuan, Feng-Lai

    2017-05-01

    To observe the morphology character of the anterior epidural space at the L 4-5 disc level and to provide an anatomical basis for safely and accurately performing a percutaneous endoscopic lumbar discectomy (PELD). Fifty-five cases with L 5 S 1 lumbar disc herniation were included in this study, and cases with L 4-5 disease were excluded. When the puncture needle reached the epidural space at the L 5 S 1 level, iohexol was injected at the pressure of 50 cm H 2 O during the PELD, then C-Arm fluoroscopy was used to obtain standard lumbar frontal and lateral images. The widths of epidural space at the level of the L 4 lower endplate, the L 5 upper endplate, as well as the middle point of the L 4-5 disc were measured from the lumbar lateral X-ray film. Epidural space at the L 4-5 disc plane performs like a trapezium chart with a short side at the head end and a long side at the tail end in the lumbar lateral X-ray radiograph, while the average widths of epidural space were 10.2 ± 2.5, 12.3 ± 2.3, and 13.8 ± 2.6 mm at the upper, middle, and lower level of the L 4-5 disc. Understanding the morphological characteristics of epidural space will contribute to improving the safety of the tranforaminal percutaneous endoscopy technique. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  12. Effect of Lemongrass Essential Oil Vapors on Microbial Dynamics and Listeria monocytogenes Survival on Rocket and Melon Stored under Different Packaging Conditions and Temperatures

    Directory of Open Access Journals (Sweden)

    Agni Hadjilouka

    2015-09-01

    Full Text Available The aim of the present study was to examine the effect of lemongrass essential oil vapors on the dynamics of surface microbiota and L. monocytogenes growth on rocket and melon under different packaging conditions and storage temperature. For that purpose, rocket and melon were placed on Expanded Polystyrene (EPS trays, sprayed with L. monocytogenes to a population of 4.5–5.0 log CFU·g−1, packaged using microperforated Oriented Polypropylene (OPP film in either air or Microperforated Active Modified Atmosphere (MAMA (initial atmosphere 5% O2, 10% CO2 including a Whatman paper containing the essential oil, without contact with the product, and stored at 0, 5, 10, and 15 °C. Application of lemongrass exhibited a bactericidal effect on enterococci and a fungistatic effect on yeast-mould populations but only during air storage of rocket. The former took place at all temperatures and the latter only at 10 and 15 °C. No effect on shelf life of both products was recorded. However, an important effect on the sensorial properties was observed; during the first 4–5 days of storage both products were organoleptically unacceptable. Regarding MAMA packaging, it affected only Pseudomonas spp. population resulting in a reduction of 1–2 log CFU·g−1 in both products.

  13. Effect of Lemongrass Essential Oil Vapors on Microbial Dynamics and Listeria monocytogenes Survival on Rocket and Melon Stored under Different Packaging Conditions and Temperatures

    Science.gov (United States)

    Hadjilouka, Agni; Polychronopoulou, Melissanthi; Paramithiotis, Spiros; Tzamalis, Periklis; Drosinos, Eleftherios H.

    2015-01-01

    The aim of the present study was to examine the effect of lemongrass essential oil vapors on the dynamics of surface microbiota and L. monocytogenes growth on rocket and melon under different packaging conditions and storage temperature. For that purpose, rocket and melon were placed on Expanded Polystyrene (EPS) trays, sprayed with L. monocytogenes to a population of 4.5–5.0 log CFU·g−1, packaged using microperforated Oriented Polypropylene (OPP) film in either air or Microperforated Active Modified Atmosphere (MAMA) (initial atmosphere 5% O2, 10% CO2) including a Whatman paper containing the essential oil, without contact with the product, and stored at 0, 5, 10, and 15 °C. Application of lemongrass exhibited a bactericidal effect on enterococci and a fungistatic effect on yeast-mould populations but only during air storage of rocket. The former took place at all temperatures and the latter only at 10 and 15 °C. No effect on shelf life of both products was recorded. However, an important effect on the sensorial properties was observed; during the first 4–5 days of storage both products were organoleptically unacceptable. Regarding MAMA packaging, it affected only Pseudomonas spp. population resulting in a reduction of 1–2 log CFU·g−1 in both products. PMID:27682104

  14. The influence of time of maternal exposure to 2,4,5,2',4',5'-hexachlorobiphenyl on its accumulation in their nursing offspring

    International Nuclear Information System (INIS)

    Gallenberg, L.A.; Ring, B.J.; Vodicnik, M.J.

    1990-01-01

    2,4,5,2',4',5'-Hexachlorobiphenyl (6-CB) is mobilized from rodent tissues during the lipid depletion associated with food restriction or lactation, the latter condition resulting in the substantial elimination of the maternal body burden of the chemical to nursing offspring. The present study was undertaken to determine whether the rate and/or magnitude of accumulation of 6-CB in nursing offspring differed with time following PCB administration to the maternal animal. Female ICR mice were administered two doses of 6-CB. Group I animals received [14C]-6-CB as weanlings (15-20 g) followed by unlabeled 6-CB 5 weeks later, after mating, on Day 1 of gestation. Group II received unlabeled 6-CB as weanlings and [14C]-6-CB on Day 1 of gestation. Thus, 14C identified the mobilization and elimination of either the first or the second dose of 6-CB in the treatment groups (I = [14C]-6-CB, 6-CB; II = 6-CB, [14C]-6-CB). Both groups of animals retained approximately 80% of the administered radiolabeled dose. The tissue distribution of [14C]-6-CB in group II as a percentage of the body burden was not different from that in group I as determined from maternal tissue concentrations on Day 14 of gestation. The percentage of the maternal body burden of [14C]-6-CB accumulated in suckling offspring of group II mothers was significantly greater than that in group I offspring on Day 1 (I, 2.2 +/- 0.5%; II, 3.5 +/- 0.4%), Day 3 (I, 14.8 +/- 1.9%; II, 24.6 +/- 2.7%), Day 5 (I, 16.8 +/- 1.4%; II, 24.8 +/- 0.8%), and Day 12 (I, 32.3 +/- 0.5%; II, 45.5 +/- 1.7%) postpartum. This differential elimination was reflected in the t1/2 of elimination of the radiolabeled dose from parametrial fat during lactation, which was significantly longer in group I (14 days) than group II maternal animals (9 days)

  15. The effect of diet and litter size on the elimination of 2,4,5,2',4',5'-[14C]hexachlorobiphenyl from lactating mice

    International Nuclear Information System (INIS)

    Ring, B.J.; Seitz, K.R.; Gallenberg, L.A.; Vodicnik, M.J.

    1990-01-01

    It was shown that 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) administered to adult female mice accumulated in their nursing offspring more rapidly than a dose administered to weanling mice when treated animals were bred at equivalent ages. This suggested that the PCB was eliminated from the maternal animal relative to its time of sequestration into storage depots. Using a model which more closely approximates conditions during human lactation, the influence of a high-fat diet and decreased litter size on this phenomenon was examined. Female ICR mice were treated with 4 mg/kg [14C]-6-CB as 13-g weanlings (dW) at 3 weeks of age or as adults (dA) at 11 weeks of age. All animals were mated at 11 weeks of age. On Day 1 of pregnancy, mice were placed on a low-fat (11.5% of the total calories) or high-fat (43.8% of total calories) diet. At parturition, litters were adjusted to either two or eight within each diet group. Elimination of maternal 6-CB was determined by assessing radioactivity in offspring carcasses on Day 15 of gestation or Day 1, 3, 5, 10, or 15 postpartum. Consumption of a high-fat diet significantly extended the t1/2 of elimination of 6-CB from mothers nursing a litter of two in the dW group (low fat = 7.3 days; high fat = 12.4 days) and in both the dW and dA groups nursing litters of eight (dW: low fat = 4.6 days; high fat = 6.8 days; and dA: low fat = 1.8 days; high fat = 3.0 days). Within diet and group, reducing litter size to two also significantly decreased the rate of elimination of 6-CB from maternal animals. 6-CB was eliminated to offspring more rapidly from the dA group when compared to the dW group regardless of diet in animals nursing litters of eight. This relationship was not observed in maternal animals nursing litters of two. In general, exposure to a high-fat diet increased the t1/2 of elimination of 6-CB from maternal animals

  16. Intrauterine inoculation of minipigs with Chlamydia trachomatis during diestrus establishes a longer lasting infection compared to vaginal inoculation during estrus

    DEFF Research Database (Denmark)

    Lorenzen, Emma; Follmann, Frank; Secher, Jan O

    2017-01-01

    Advanced animal models, such as minipigs, are needed for the development of a globally requested human Chlamydia vaccine. Previous studies have shown that vaginal inoculation of sexually mature Göttingen minipigs with Chlamydia trachomatis resulted in an infection lasting only 3-5 days. The aim...... resulted in a longer lasting infection (at least 10 days) compared to estrus (3-5 days). Furthermore, we found a significant C. trachomatis specific IFN-γ response in pigs inoculated during estrus correlating with the accelerated clearance of infection in these pigs. These findings suggest...

  17. Inoculating against Pro-Plagiarism Justifications: Rational and Affective Strategies

    Science.gov (United States)

    Compton, Josh; Pfau, Michael

    2008-01-01

    Student plagiarism continues to threaten academic integrity. This investigation assessed whether an inoculation message strategy could combat university plagiarism by protecting student attitudes against pro-plagiarism justification arguments. Additionally, we sought theoretical confirmation of previous findings on involvement and accessibility in…

  18. Inoculation, colonization and distribution of fungal endophytes in ...

    African Journals Online (AJOL)

    Mo

    and for a part or whole of their life cycle live symptomlessly within the plant. ... inoculated in tissue culture banana plants, must occur at high frequencies in the plant and be able to persist in ... For instance, the influence of fungal endophytes.

  19. Effect of Inoculating Bradyrhizobium on Phosphorus Use Efficiency ...

    African Journals Online (AJOL)

    3 School of Natural Resources Management and Environmental Sciences, ..... was produced per unit of P applied by un-inoculated, SB6B1 and Legumefix ... meet the high energy costs for adenosine triphosphate (ATP) synthesis .... Kumar and Kairon (1980) also determined an apparent P .... Prentice Hall, New Jersey.

  20. Inoculation effects of two South African cyanobacteria strains on ...

    African Journals Online (AJOL)

    Two South African cyanobacteria strains (coded 3g and 7e) of the genus Nostoc were evaluated for improvement of the aggregate stability of a silty loam soil with low organic C content and compared with Nostoc strain 9v isolated from a Tanzanian soil. The soil was either cropped with maize or non-cropped and inoculated ...

  1. Effect of salinity and inoculation with Azosprillium on carbohydrate ...

    African Journals Online (AJOL)

    The measured parameters were chlorophyll fluorescence, photosynthesis (Ps) rates, carbohydrates, nitrate, ammonium and protein content, nitrogenase activity, yield and yield components. The results showed that salinity decreased plant height and grain yield (GY) in all levels. GY reduction in the inoculated treatment was ...

  2. Effects of bacterial inoculants and an enzyme on the fermentation ...

    African Journals Online (AJOL)

    ... the effects of bacterial inoculation and cellulase on the fermentation quality of ensiled whole-crop sweet sorghum (WCSS, Sorghum bicolor L. Moench). The WCSS (323 g dry matter (DM)/kg, 251 g water soluble carbohydrates (WSC)/kg DM, 43 g crude protein (CP)/kg DM and 439 g neutral detergent fibre (NDF)/kg DM) ...

  3. Effect of plant-growth-promoting rhizobacteria inoculation on plant ...

    African Journals Online (AJOL)

    A field experiment was conducted in a wet season (Kharif) to study the effects of plant growth-promoting rhizobacteria(PGPR) inoculation on agronomic traits and productivity of Basmati rice (cv. 'Pusa Basmati 1401') in a randomized block with twelve treatments. We evaluated one bacterial (Providencia sp. PW5) and one ...

  4. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  5. Effect of arbuscular mycorrhizal fungal inoculation on growth, and ...

    African Journals Online (AJOL)

    The aim of our work was to assess the effect of inoculation with three arbuscular mycorrhizal fungi (AMF) (Rhizoglomus aggregatum (N.C. Schenck and G.S. Sm.) Sieverd., G.A. Silva and Oeh., Funneliformis mosseae (T.H. Nicolson and Gerd.) C. Walker and A. Schüssler. and Rhizoglomus intraradices (N.C. Schenck and ...

  6. Production of cell wall enzymes in pepper seedlings, inoculated with ...

    African Journals Online (AJOL)

    Pepper seedlings inoculated with arbuscular mycorrhizal AM fungus, Glomus etunicatum, produced cellulase, polygal-acturonase and pectin methylestrase enzymes. The activities of the enzymes increased as the pepper seedlings matured in age, showing that the activity of the enzymes in the seedlings was age mediated.

  7. Effects of bacterial inoculation on the fermentation characteristics ...

    African Journals Online (AJOL)

    The effect of bacterial inoculation on the fermentation and aerobic stability of two ensiled whole plant soybean (WPSB) cultivars was determined in a 2 x 2 factorial design. Two WPSB cultivars, Link LF6466 and Pannar 522 RR, were harvested at their R6 growth stage, chopped to 25 mm and ensiled in 1.5 L anaerobic jars.

  8. Polymers selection for a liquid inoculant of Azospirillum brasilense ...

    African Journals Online (AJOL)

    In this study, we used a method of accelerated degradation to select a polymer and a concentration to maintain cell stability of a liquid inoculant based on the strain C16 Azospirillum brasilense. A screening at 45°C was made to compare the protectant effect of five polymers on the viability of the strain (p/v): carrageenan ...

  9. Inoculation of peritoneal dialysate fluid into blood culture bottles ...

    African Journals Online (AJOL)

    The aim of the study was to determine if direct inoculation of peritoneal fluid into Bactec blood culture bottles would improve the positive bacteriological yield compared with conventional techniques in continuous ambulatory peritoneal dialysis (CAPD) patients with peritonitis. All patients presenting with suspected peritonitis ...

  10. Prevalence and quantification of Listeria monocytogenes in beef offal at retail level in Selangor, Malaysia

    Science.gov (United States)

    Kuan, Chee Hao; Wong, Woan Chwen; Pui, Chai Fung; Mahyudin, Nor Ainy; Tang, John Yew Huat; Nishibuchi, Mitsuaki; Radu, Son

    2013-01-01

    A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis. PMID:24688507

  11. Modeling the growth of Listeria monocytogenes in soft blue-white cheese

    DEFF Research Database (Denmark)

    Rosshaug, Per Sand; Detmer, Ann; Ingmer, Hanne

    2012-01-01

    The aim of this study was to develop a predictive model simulating growth over time of the pathogenic bacterium Listeria monocytogenes in a soft blue-white cheese. The physicochemical properties in a matrix such as cheese are essential controlling factors influencing the growth of L. monocytogenes....... We developed a predictive tertiary model of the bacterial growth of L. monocytogenes as a function of temperature, pH, NaCl, and lactic acid. We measured the variations over time of the physicochemical properties in the cheese. Our predictive model was developed based on broth data produced...... production and retail conditions showed that the number of L. monocytogenes cells increases 3 to 3.5 log within the shelf life of the cheese....

  12. Prevalence and quantification of Listeria monocytogenes in beef offal at retail level in Selangor, Malaysia.

    Science.gov (United States)

    Kuan, Chee Hao; Wong, Woan Chwen; Pui, Chai Fung; Mahyudin, Nor Ainy; Tang, John Yew Huat; Nishibuchi, Mitsuaki; Radu, Son

    2013-12-01

    A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

  13. Prevalence and quantification of Listeria monocytogenes in beef offal at retail level in Selangor, Malaysia

    Directory of Open Access Journals (Sweden)

    Chee Hao Kuan

    2013-12-01

    Full Text Available A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9 from three wet markets (A, B, and C in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

  14. PRÉVALENCE DE LISTERIA MONOCYTOGENES DANS LE LAIT CRU DE VACHE AU LIBAN NORD

    Directory of Open Access Journals (Sweden)

    Imad al Kassaa

    2016-06-01

    Full Text Available Al Kassaa Imad, Khaled el Omari, Marwa Saati, Bachar Ismail and Monzer Hamze. 2016. Prevalence of Listeria monocytogenes in raw cow milk in north Lebanon. Lebanese Science Journal, 17(1: 39-45. Listeriosis, although a zoonosis, is an invasive disease that can affect newborns, pregnant women and immunocompromised adults. Clinical manifestations can be expressed by febrile gastroenteritis, invasive forms including severe sepsis, meningitis, rhombencephalitis, prenatal infections and abortions. Species of Listeria bacteria are ubiquitous and adaptable to the environment in animal and plant foods. This study aimed to determine the prevalence of Listeria monocytogenes in 100 samples of fresh cow milk collected from different areas of North Lebanon. Listeria monocytogenes was detected by using the Grand VIDAS technique (Biomérieux France. The results obtained revealed the absence of Listeria monocytogenes in all analyzed samples.

  15. Genotypic profile of Listeria monocytogenes isolated in refrigerated chickens in southern Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Karla Sequeira Mendonça

    2016-01-01

    Full Text Available ABSTRACT: Listeria monocytogenes is of notable concern to the food industry, due to its ubiquitous nature and ability to grow in adverse conditions. This study aimed to determine the genotypic profile of L. monocytogenes strains isolated from refrigerated chickens marketed in the southern part of Rio Grande do Sul, Brazil. The strains of L. monocytogenes isolated were characterized by serotyping and Pulsed Field Gel Electrophoresis (PFGE. Three different serotypes (1/2a, 1/2b and 4e were evaluated by PFGE, and the macrorestriction patterns utilizing enzymes AscI and ApaI, revealed five different pulsotypes. The presence of such varied genotypic profiles demonstrates the prevalence of L. monocytogenes contamination of chicken processing environments, which combined with ineffective cleaning procedures, allowing the survival, adaptation and proliferation of these pathogens, not only in the processing environment, but also in local grocery stores.

  16. Prevalence and contamination levels of listeria monocytogenes in ready-to-eat foods in Tokyo, Japan.

    Science.gov (United States)

    Shimojima, Yukako; Ida, Miki; Nakama, Akiko; Nishino, Yukari; Fukui, Rie; Kuroda, Sumiyo; Hirai, Akihiko; Kai, Akemi; Sadamasu, Kenji

    2016-08-01

    We surveyed prevalence and contamination levels of Listeria monocytogenes in ready-to-eat foods between 2000 and 2012 in Tokyo. L. monocytogenes was isolated from 52 (1.7%) out of 2,980 samples. Comparing the prevalence in the study period, 2.2% were positive in the former period (2000-2005) and 1.2% in the latter (2006-2012). Using the most probable number (MPN) technique, 32 samples were contaminated with fewer than 0.3 L. monocytogenes/g, 10 samples with 0.3-1.0/g and 4 samples with more than 1.0/g (the maximum was 2.3/g). The most common serovar was 1/2a, followed by 1/2b, 4b and 1/2c. We revealed that ready-to-eat foods in Tokyo were contaminated with L. monocytogenes, although the contamination levels were low.

  17. NATURAL ATYPICAL LISTERIA INNOCUA STRAINS WITH LISTERIA MONOCYTOGENES PATHOGENICITY ISLAND 1 GENES

    Science.gov (United States)

    The detection of the human foodborne pathogen, Listeria monocytogenes, in food, environmental samples and clinical specimens associated with cases of listeriosis, a rare but high mortality-rate disease, requires distinguishing the pathogen from other Listeria species. Speciation...

  18. Characteristics of the biologically active 35-kDa metalloprotease virulence factor from Listeria monocytogenes

    NARCIS (Netherlands)

    Coffey, A; van den Burg, B; Veltman, R; Abee, T

    Listeria monocytogenes, a facultative intracellular pathogen, synthesizes an extracellular protease which is responsible for the maturation of phosphatidylcholine phospholipase C (lecithinase), a virulence factor involved in cell-to-cell spread. This work describes the environmental parameters

  19. Listeriolysin S: A bacteriocin from epidemic Listeria monocytogenes strains that targets the gut microbiota.

    Science.gov (United States)

    Quereda, Juan J; Meza-Torres, Jazmín; Cossart, Pascale; Pizarro-Cerdá, Javier

    2017-07-04

    Listeria monocytogenes is a Gram-positive food-borne pathogen that in humans may traverse the intestinal, placental and blood/brain barriers, causing gastroenteritis, abortions and meningitis. Crossing of these barriers is dependent on the bacterial ability to enter host cells, and several L. monocytogenes surface and secreted virulence factors are known to facilitate entry and the intracellular lifecycle. The study of L. monocytogenes strains associated to human listeriosis epidemics has revealed the presence of novel virulence factors. One such factor is Listeriolysin S, a thiazole/oxazole modified microcin that displays bactericidal activity and modifies the host microbiota during infection. Our recent results therefore highlight the interaction of L. monocytogenes with gut microbes as a crucial step in epidemic listeriosis. In this article, we will discuss novel implications for this family of toxins in the pathogenesis of diverse medically relevant microorganisms.

  20. Inhibitory effect of liposome-entrapped lemongrass oil on the growth of Listeria monocytogenes in cheese.

    Science.gov (United States)

    Cui, H Y; Wu, J; Lin, L

    2016-08-01

    Listeria monocytogenes infection in dairy products is of mounting public concern. To inhibit bacterial growth, we engineered stimuli-responsive liposomes containing lemongrass oil for this study. The controlled release of liposome-entrapped lemongrass oil is triggered by listerolysin O, secreted by L. monocytogenes. We investigated the antibiotic activities of lemongrass oil liposomes against L. monocytogenes in cheese. We also assessed their possible effects on the quality of the cheese. Liposomes containing lemongrass oil (5.0mg/mL) presented the optimal polydispersity index (0.246), zeta-potential (-58.9mV) and entrapment efficiency (25.7%). The liposomes displayed satisfactory antibiotic activity against L. monocytogenes in cheese over the storage period at 4°C. We observed no effects on the physical and sensory properties of the cheese after the liposome treatment. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  1. Evaluation of a monoclonal antibody able to detect live Listeria monocytogenes and Listeria innocua

    DEFF Research Database (Denmark)

    Sølve, Marianne; Boel, Jeppe; Nørrung, Birgit

    2000-01-01

    A monoclonal Listeria antibody, designated B4, was evaluated. The ability of the antibody to bind to viable bacteria belonging to Listeria spp, compared to bacteria of the same species killed by beat treatment, acid or base treatment, sanitizers, and irradiation was examined. The antibody was found...... to react with viable L. monocytogenes and L. innocua, but not with heat-killed (72 degrees C, 5 min) strains of these organisms. When L. monocytogenes and L. innocua were killed by methods other than heat treatment, it was ambiguous whether the antibody detected the organism or not. It was concluded...... that the B4 antibody has potential to be used in an immune capture step to capture live L, monocytogenes and L. innocua from foods prior to identification of L. monocytogenes by polymerase chain reaction (PCR)....

  2. Internalization of Listeria monocytogenes in cantaloupes during dump tank washing and hydrocooling

    Science.gov (United States)

    Recent listeriosis outbreaks and recalls associated with cantaloupes urge for studies to understand the mechanisms of cantaloupe contamination by Listeria monocytogenes. Postharvest practices such as washing and hydrocooling were suggested to facilitate the contamination of fresh fruits by human pat...

  3. How a routine checking of Escherichia coli in retailed food of animal origin can protect consumers against exposition to Campylobacter spp. and Listeria monocytogenes?

    Directory of Open Access Journals (Sweden)

    Trajković-Pavlović Ljiljana

    2010-01-01

    Full Text Available Background/Aim. According to the literature that has been published over the last two decades Campylobacter spp i Listeria monocitogens can be identified as causes of numerous diseases derived by consuming food of animal origin. The purpose of this paper was to find out how established national microbiological criteria of the Republic of Serbia on food safety in retailed food of animal origin could contribute to consumer's protection against exposition to foodborne pathogens such as Campylobacter spp. and Listeria monocytogenes. Methods. During a routine microbiological safety control of randomly selected 60 samples of fresh poultry meat, 30 samples of other fresh meat readymade for grilling, 30 samples of sausage products, 37 samples of heattreated meat, 39 samples of toppings for fast food of animal origin and 31 samples of dairy products a national food safety criteria (Escherichia coli, aerobic plate count, Salmonella spp., coagulasa positive Staphylococcus, Proteus spp., sulphitoreducting Clostridia were applied and, as well as, testing to Campylobacter spp. and Listeria monocitogens. In determination of Campylobacter spp. and Listeria monocytogenes, food quality control methods of the Food and Agriculture Organization (FAO were applied, while in determination of the other above motioned bacteria, national provisions on microbiological methods were applied who are adjusted to the FAO ones. Results. Related to the national criteria on microbiological food safety, 88 (38.8% samples, out of the total 227 tested, were rejected. When to these results, the results of laboratory tests on Listeria monocytogens were added, a terminal number of rejected samples were not changed. When to these results, the results of Campylobacter spp. testing were added, 91 (40.1% out of the 227 samples were unsatisfied. Results of logistic regression model with occurrence of Escherichia coli as dependent variable indicated that Escherichia coli was 4.5 times likely

  4. How a routine checking of Escherichia coli in retailed food of animal origin can protect consumers against exposition to Campylobacter spp. and Listeria monocytogenes?

    Science.gov (United States)

    Trajković-Pavlović, Ljiljana; Novaković, Budimka; Martinov-Cvejin, Mirjana; Gusman, Vera; Bijelović, Sanja; Dragnić, Natasa; Balać, Dragana

    2010-08-01

    According to the literature that has been published over the last two decades Campylobacter spp i Listeria monocitogens can be identified as causes of numerous diseases derived by consuming food of animal origin. The purpose of this paper was to find out how established national microbiological criteria of the Republic of Serbia on food safety in retailed food of animal origin could contribute to consumer's protection against exposition to foodborne pathogens such as Campylobacter spp. and Listeria monocytogenes. During a routine microbiological safety control of randomly selected 60 samples of fresh poultry meat, 30 samples of other fresh meat readymade for grilling, 30 samples of sausage products, 37 samples of heat-treated meat, 39 samples of toppings for fast food of animal origin and 31 samples of dairy products a national food safety criteria (Escherichia coli, aerobic plate count, Salmonella spp., coagulasa positive Staphylococcus, Proteus spp., sulphito-reducting Clostridia) were applied and, as well as, testing to Campylobacter spp. and Listeria monocitogens. In determination of Campylobacter spp. and Listeria monocytogenes, food quality control methods of the Food and Agriculture Organization (FAO) were applied, while in determination of the other above motioned bacteria, national provisions on microbiological methods were applied who are adjusted to the FAO ones. Related to the national criteria on microbiological food safety, 88 (38.8%) samples, out of the total 227 tested, were rejected. When to these results, the results of laboratory tests on Listeria monocytogens were added, a terminal number of rejected samples were not changed. When to these results, the results of Campylobacter spp. testing were added, 91 (40.1%) out of the 227 samples were unsatisfied. Results of logistic regression model with occurrence of Escherichia coli as dependent variable indicated that Escherichia coli was 4.5 times likely to occur among samples with Campylobacter spp

  5. MicroRNA-146a Deficiency Protects against Listeria monocytogenes Infection by Modulating the Gut Microbiota

    Directory of Open Access Journals (Sweden)

    Chong-Tao Du

    2018-03-01

    Full Text Available The gut microbiota and microRNAs play important roles in the defense against infection. However, the role of miR-146a in L. monocytogenes infection and gut microbiota remains unclear. We tried to determine whether miR-146a controlled L. monocytogenes infection by regulating the gut microbiota. Wild-type and miR-146a-deficient mice or macrophages were used to characterize the impact of miR-146a on animal survival, cell death, bacterial clearance, and gut microbiota following L. monocytogenes challenge. We found that L. monocytogenes infection induced miR-146a expression both in vitro and in vivo. When compared to wild-type mice, miR-146a-deficient mice were more resistant to L. monocytogenes infection. MiR-146a deficiency in macrophages resulted in reduced invasion and intracellular survival of L. monocytogenes. High-throughput sequencing of 16S rRNA revealed that the gut microbiota composition differed between miR-146a-deficient and wild-type mice. Relative to wild-type mice, miR-146a-deficient mice had decreased levels of the Proteobacteria phylum, Prevotellaceae family, and Parasutterella genus, and significantly increased short-chain fatty acid producing bacteria, including the genera Alistipes, Blautia, Coprococcus_1, and Ruminococcus_1. Wild-type mice co-housed with miR-146a-deficient mice had increased resistance to L. monocytogenes, indicating that miR-146a deficiency guides the gut microbiota to alleviate infection. Together, these results suggest that miR-146a deficiency protects against L. monocytogenes infection by regulating the gut microbiota.

  6. Modeling and predicting the growth boundary of Listeria monocytogenes in lightly preserved seafood

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Dalgaard, Paw

    2007-01-01

    The antimicrobial effect of diacetate and lactate against Listeria monocytogenes was evaluated in challenge tests with vacuum-packaged or modified atmosphere packaged (MAP) cold-smoked salmon, marinated salmon, cold-smoked Greenland halibut, marinated Greenland halibut, and gravad salmon. MAP col...... characteristics required to prevent the growth of L. monocytogenes, thereby making it possible to identify critical control points, and is useful for compliance with the new European Union regulation on ready-to-eat foods (EC 2073/2005)....

  7. An insight into the isolation, enumeration and molecular detection of Listeria monocytogenes in food

    Directory of Open Access Journals (Sweden)

    Jodi Woan-Fei Law

    2015-11-01

    Full Text Available Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria Enrichment Broth (BLEB, Fraser broth and University of Vermont Medium (UVM Listeria enrichment broth are recommended by regulatory agencies such as FDA-BAM, USDA-FSIS and ISO. Many plating media are available for the isolation of L. monocytogenes, for instance, PALCAM, Oxford and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. MPN technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction (PCR, multiplex polymerase chain reaction (mPCR, real-time/quantitative polymerase chain reaction (qPCR, nucleic acid sequence-based amplification (NASBA, loop-mediated isothermal amplification (LAMP, DNA microarray and Next Generation Sequencing (NGS technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labour-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features.

  8. Incidence of Listeria monocytogenes and Listeria spp. in a small-scale mushroom production facility.

    Science.gov (United States)

    Viswanath, Prema; Murugesan, Latha; Knabel, Stephen J; Verghese, Bindhu; Chikthimmah, Naveen; Laborde, Luke F

    2013-04-01

    Listeria monocytogenes is a foodborne pathogen of significant concern to the agricultural and food processing industry because of its ability to grow and persist in cool and moist environments and its association with listeriosis, a disease with a very high mortality rate. Although there have been no listeriosis outbreaks attributed to fresh mushrooms in the United States, retail surveys and recalls are evidence that L. monocytogenes contamination of mushrooms (Agaricus bisporus) can occur. The objective of this study was to determine the prevalence of Listeria spp., including L. monocytogenes, in a small-scale mushroom production facility on the campus of the Pennsylvania State University in the United States. Of 184 samples taken from five production zones within the facility, 29 (15.8%) samples were positive for Listeria spp. Among the Listeria spp. isolates, L. innocua was most prevalent (10.3%) followed by L. welshimeri (3.3%), L. monocytogenes (1.6%), and L. grayi (0.5%). L. monocytogenes was recovered only from the phase I raw material composting area. Isolates of L. monocytogenes were confirmed and serotyped by multiplex PCR. The epidemiological relatedness of the three L. monocytogenes isolates to those serotypes or lineages frequently encountered in listeriosis infections was determined by multi-virulence-locus sequence typing using six virulence genes, namely, prfA, inlB, inlC, dal, clpP, and lisR. The phylogenetic positions of the three isolates in the dendrogram prepared with data from other isolates of L. monocytogenes showed that all isolates were grouped with serotype 4a, lineage IIIA. To date, this serotype has rarely been reported in foodborne disease outbreaks.

  9. The influence of Listeria monocytogenes cells on the primary immunologic response in irradiated mice

    International Nuclear Information System (INIS)

    Borowski, J.; Jokoniuk, P.

    1977-01-01

    The influence of killed Listeria monocytogenes cells on the primary immunologic response in mice irradiated with 300 or 500 R was studied. The immunologic response of the mice to sheep red blood cells used as antigen was assessed at the cellular level (by counting PFC) and humoral level. Injection of killed Listeria monocytogenes cells before irradiation of the mice diminished the immunosuppressive effect of roentgen radiation. Injection of the cells after irradiation accelerated regeneration of immunologic reactivity in the irradiated mice. (author)

  10. Occurrence and antimicrobial resistance patterns of Listeria monocytogenes isolated from vegetables

    OpenAIRE

    Byrne,Vanessa de Vasconcelos; Hofer,Ernesto; Vallim,Deyse Christina; Almeida,Rogeria Comastri de Castro

    2016-01-01

    Abstract Although the consumption of fresh and minimally processed vegetables is considered healthy, outbreaks related to the contamination of these products are frequently reported. Among the food-borne pathogens that contaminate vegetables is Listeria monocytogenes, a ubiquitous organism that exhibits the ability to survive and multiply at refrigerated temperatures. This study aimed to evaluate the occurrence of L. monocytogenes in vegetables as well as the antimicrobial resistance of isola...

  11. Phenotypic and Genotypic Characteristics of Listeria monocytogenes Isolated From Dairy and Meat Products

    OpenAIRE

    Bahador; Sadeghi Kalani; Valian; Irajian; Lotfollahi

    2015-01-01

    Background Listeria monocytogenes is a foodborne pathogen and a serious threat to the public health in the world. Consumption of traditional foods such as dairy and meat products can be a major reason for relative abundance and isolation of these bacteria. Objectives The purpose of this study was to determine the phenotypic and genotypic characteristics of L. monocytogenes strains isolated from dairy and meat products. ...

  12. Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface.

    Science.gov (United States)

    de Grandi, Aline Zago; Pinto, Uelinton Manoel; Destro, Maria Teresa

    2018-04-12

    Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σ B , in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.

  13. MicroRNA-146a Deficiency Protects against Listeria monocytogenes Infection by Modulating the Gut Microbiota.

    Science.gov (United States)

    Du, Chong-Tao; Gao, Wei; Ma, Ke; Yu, Shui-Xing; Li, Na; Yan, Shi-Qing; Zhou, Feng-Hua; Liu, Zhen-Zhen; Chen, Wei; Lei, Lian-Cheng; Yang, Yong-Jun; Han, Wen-Yu

    2018-03-26

    The gut microbiota and microRNAs play important roles in the defense against infection. However, the role of miR-146a in L. monocytogenes infection and gut microbiota remains unclear. We tried to determine whether miR-146a controlled L. monocytogenes infection by regulating the gut microbiota. Wild-type and miR-146a-deficient mice or macrophages were used to characterize the impact of miR-146a on animal survival, cell death, bacterial clearance, and gut microbiota following L. monocytogenes challenge. We found that L. monocytogenes infection induced miR-146a expression both in vitro and in vivo. When compared to wild-type mice, miR-146a-deficient mice were more resistant to L. monocytogenes infection. MiR-146a deficiency in macrophages resulted in reduced invasion and intracellular survival of L. monocytogenes . High-throughput sequencing of 16S rRNA revealed that the gut microbiota composition differed between miR-146a-deficient and wild-type mice. Relative to wild-type mice, miR-146a-deficient mice had decreased levels of the Proteobacteria phylum, Prevotellaceae family, and Parasutterella genus, and significantly increased short-chain fatty acid producing bacteria, including the genera Alistipes , Blautia , Coprococcus_1, and Ruminococcus_1 . Wild-type mice co-housed with miR-146a-deficient mice had increased resistance to L. monocytogenes , indicating that miR-146a deficiency guides the gut microbiota to alleviate infection. Together, these results suggest that miR-146a deficiency protects against L. monocytogenes infection by regulating the gut microbiota.

  14. Distribution of the bacteria Listeria monocytogenes in the western part of the Sea of Okhotsk

    Science.gov (United States)

    Terekhova, V. E.; Sosnin, V. A.; Buzoleva, L. S.; Shakirov, R. B.

    2010-04-01

    The Amur River’s influence on the distribution of the opportunistic bacteria Listeria monocytogenes in the western part of the Sea of Okhotsk is discussed. The presence of Listeria in the seawater, sea ice, and sediments on the northeastern Sakhalin shelf and slope supports the idea of its connection with the Amur River discharge. The hypothesis of the allochtonic parentage of L. monocytogenes in the sea’s development is proved.

  15. Longitudinal monitoring of Listeria monocytogenes and Listeria phages in seafood processing environments in Thailand.

    Science.gov (United States)

    Vongkamjan, Kitiya; Benjakul, Soottawat; Kim Vu, Hue Thi; Vuddhakul, Varaporn

    2017-09-01

    Listeria monocytogenes is a foodborne pathogen commonly found in environments of seafood processing, thus presenting a challenge for eradication from seafood processing facilities. Monitoring the prevalence and subtype diversity of L. monocytogenes together with phages that are specific to Listeria spp. ("Listeria phages") will provide knowledge on the bacteria-phage ecology in food processing plants. In this work, a total of 595 samples were collected from raw material, finished seafood products and environmental samples from different sites of a seafood processing plant during 17 sampling visits in 1.5 years of study. L. monocytogenes and Listeria spp. (non-monocytogenes) were found in 22 (3.7%) and 43 (7.2%) samples, respectively, whereas 29 Listeria phages were isolated from 9 (1.5%) phage-positive samples. DNA fingerprint analysis of L. monocytogenes isolates revealed 11 Random Amplified Polymorphic DNA (RAPD) profiles, with two subtypes were frequently observed over time. Our data reveal a presence of Listeria phages within the same seafood processing environments where a diverse set of L. monocytogenes subtypes was also found. Although serotype 4b was observed at lower frequency, data indicate that isolates from this seafood processing plant belonged to both epidemiologically important serotypes 1/2a and 4b, which may suggest a potential public health risk. Phages (all showed a unique genome size of 65 ± 2 kb) were classified into 9 host range groups, representing both broad- and narrow-host range. While most L. monocytogenes isolates from this facility were susceptible to phages, five isolates showed resistance to 12-20 phages. Variations in phage host range among Listeria phages isolated from food processing plant may affect a presence of a diverse set of L. monocytogenes isolates derived from the same processing environment in Thailand. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. An insight into the isolation, enumeration, and molecular detection of Listeria monocytogenes in food

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are

  17. Accuracy Evaluation of C4.5 and Naive Bayes Classifiers Using Attribute Ranking Method

    Directory of Open Access Journals (Sweden)

    S. Sivakumari

    2009-03-01

    Full Text Available This paper intends to classify the Ljubljana Breast Cancer dataset using C4.5 Decision Tree and Nai?ve Bayes classifiers. In this work, classification is carriedout using two methods. In the first method, dataset is analysed using all the attributes in the dataset. In the second method, attributes are ranked using information gain ranking technique and only the high ranked attributes are used to build the classification model. We are evaluating the results of C4.5 Decision Tree and Nai?ve Bayes classifiers in terms of classifier accuracy for various folds of cross validation. Our results show that both the classifiers achieve good accuracy on the dataset.

  18. Ballooning-mirror instability and internally driven Pc 4--5 wave events

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Qian, Q.; Takahashi, K.; Lui, A.T.Y.

    1994-03-01

    A kinetic-MHD field-aligned eigenmode stability analysis of low frequency ballooning-mirror instabilities has been performed for anisotropic pressure plasma sin the magnetosphere. The ballooning mode is mainly a transverse wave driven unstable by pressure gradient in the bad curvature region. The mirror mode with a dominant compressional magnetic field perturbation is excited when the product of plasma beta and pressure anisotropy (P perpendicular /P parallel > 1) is large. From the AMPTE/CCE particle and magnetic field data observed during Pc 4--5 wave events the authors compute the ballooning-mirror instability parameters and perform a correlation study with the theoretical instability threshold. They find that compressional Pc 5 waves approximately satisfy the ballooning-mirror instability condition, and transverse Pc 4--5 waves are probably related to resonant ballooning instabilities with small pressure anisotropy

  19. Performance of six 4.5 m SSC [Superconducting Super Collider] dipole model magnets

    International Nuclear Information System (INIS)

    Willen, E.; Dahl, P.; Cottingham, J.

    1986-01-01

    Six 4.5 m long dipole models for the proposed Superconducting Super Collider have been successfully tested. The magnets are cold-iron (and cold bore) 1-in-1 dipoles, wound with current density-graded high homogeneity NbTi cable in a two-layer cos θ coil of 40 mm inner diameter. The coil is prestressed by 15 mm wide stainless steel collars, and mounted in a circular, split iron yoke of 267 mm outer diameter, supported in a cylindrical yoke containment vessel. At 4.5 K the magnets reached a field of about 6.6 T with little training, or the short sample limit of the conductor, and in subcooled (2.6 - 2.4 K) liquid, 8 T was achieved. The allowed harmonics were close to the predicted values, and the unallowed harmonics small. The sextupole trim coil operated well above the required current with little training

  20. Performance of three 4.5 m dipoles for SSC reference design D

    International Nuclear Information System (INIS)

    Dahl, P.; Cottingham, J.; Fernow, R.

    1985-01-01

    Three 4.5 m long dipoles for Reference Design D of the proposed Superconducting Super Collider have been successfully tested. The magnets are cold-iron (and cold bore) 1-in-1 dipoles, wound with current density-graded high homogeneity NbTi cable in a two-layer cos theta coil of 40 mm inner diameter. The coil is prestressed by 15 mm wide stainless steel collars, and mounted in a circular, split iron yoke of 267 mm outer diameter, supported in a cylindrical yoke containment vessel. At 4.5 K the magnets reached a field of about 6.6T with little training, or the short sample limit of the conductor, and in subcooled (2.6 to 2.4 K) liquid, 8T was achieved. The allowed harmonics were close to the predicted values, and the unallowed harmonics small. The sextupole trim coil operated at eight times the required current without training

  1. Fatigue assessment of central support structure coil jacket of 4.5 MJ SMES

    International Nuclear Information System (INIS)

    Akhter, Javed; Bhunia, Uttam; Mondal, Bidhan Chandra; Nandi, Chinmay; Pal, Gautam; Saha, Subimal

    2013-01-01

    The Superconducting coil of 4.5 SMES will be of sector-toroidal type with 8 sectors. The maximum coil current will be 1200 Amperes. During its life time the SMES will be subjected to several cycles of charging and discharging. Thus the structural assessment of coil central support structure and the Liquid Helium Jacket, which comprises of the stress analysis and the fatigue life assessment, is a critical part of the design. In this paper fatigue life assessment of the 4.5 MJ SMES coil central support structure and the Liquid Helium Jacket together with the related stress analysis is presented. Coupled electromagnetic and Structural analysis using the commercial finite element analysis package ANSYS is performed. Considering the cyclic symmetry of the coil assembly, only 1/8th of the assembly is modelled. (author)

  2. Characterization of the Emerging Salmonella 4,[5],12:i:- in Danish Animal Production

    DEFF Research Database (Denmark)

    Argüello, Hector; Sørensen, Gitte; Carvajal, Ana

    2014-01-01

    Abstract The monophasic Salmonella variant with the antigenic formula Salmonella 4,[5],12:i:- has emerged in the last decade as one of the main serotypes related to human salmonellosis. In the present study, a collection of 94 isolates of the S. 4,12:i:- and S. 4,5,12:i:- coming from Danish farm ...... in Danish food animal production with well-characterized clones that are described by previous studies, demonstrating the emergence and spread of this serotype in Denmark....... animals, swine (86), cattle (7), and poultry (1), with well-defined identification was further typed by polymerase chain reaction serotyping, phage typing, and molecular typing (polymerase chain reaction and multilocus variable-number tandem-repeat analysis [MLVA]). Moreover, the determination...

  3. Modified Sierpinski Gasket Patch Antenna for UMTS and 2.4/5.2 WLAN

    Directory of Open Access Journals (Sweden)

    Y. E. Ali

    2013-05-01

    Full Text Available A modified Sierpinski Gasket fractal antenna for multiband application is proposed in this paper. The modified ground plane and the microstrip feed are used to obtain the wider bandwidth at the resonance frequency. The antenna is designed and printed on two layers FR-4 substrate (ϵr=4.4 and h=1.6 mm to cover the UMTS and 2.4/5.2 WLAN. The radiation pattern of the proposed antenna is similar to an omnidirectional. The proposed antenna has maximum gain of 1.88, 1.6, 4.31 dB at 2, 2.4, 5.2 GHz, respectively The properties of the antenna such as return losses, radiation pattern, input resistance and gain are determined via numerical CST Microwave Studio 2010 software.

  4. High resolution krypton M/sub 4,5/ x-ray emission spectra

    International Nuclear Information System (INIS)

    Perera, R.C.C.; Hettrick, M.C.; Lindle, D.W.

    1987-10-01

    High resolution M/sub 4,5/ (3d → 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/ΔE, is about 300 in this energy range (∼80 eV). Three dipole-allowed 3d → 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr 2+ , and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab

  5. Rhenium (5) and molybdenum (5) complexes with 4',4''(5'')-ditretbutyldibenzo-24-crown-8

    International Nuclear Information System (INIS)

    Ashurova, N.Kh.; Yakubov, K.G.; Basitova, S.M.; Tashmukhamedova, A.K.; Sajfullina, N.Zh.

    1989-01-01

    Rhenium and molybdenum complexes in +5 oxidation degree with 4',4''(5'')-ditretbutyldibenzo-24-crown-8 (L) are synthesized with 75-95 % yield. Composition and structure of compounds produced are investigated using element analysis, conductometry, IR spectroscopy, thermogravimetry methods. Oxidation degree of complexer metal is determined. It is ascertained that the compound composition corresponds to the MOLX 3 formula, where M-Re, Mo; X-Cl - , Br -

  6. Peningkatan Kemampuan Berhitung melalui Permainan Pohon Hitung Usia 4-5 Tahun di Tk

    OpenAIRE

    Wahyuni. S, Sri; Ali, Muhammad; Halida

    2016-01-01

    The method used is descriptive method with the form of classroom action research. Class Action Research Cycle consists of planning, implementation, observation, and reflection. Collecting data using observation and interview. Based on the research and the data analysis in general it can be concluded that the significant increase in the numeracy skills of children through the game tree count in children aged 4-5 years in kindergarten Hang Tuah VI Pontianak. Specifically kesimpulanya are as fol...

  7. Deterministic methods in radiation transport. A compilation of papers presented February 4--5, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Rice, A.F.; Roussin, R.W. [eds.

    1992-06-01

    The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.

  8. Deterministic methods in radiation transport. A compilation of papers presented February 4-5, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Rice, A. F.; Roussin, R. W. [eds.

    1992-06-01

    The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.

  9. Rumphellaones B and C, New 4,5-Seco-Caryophyllane Sesquiterpenoids from Rumphella

    Directory of Open Access Journals (Sweden)

    Hsu-Ming Chung

    2014-08-01

    Full Text Available Two new 4,5-seco-caryophyllane sesquiterpenoids, rumphellaones B (1 and C (2, which were found to possess unprecedented γ-lactone moieties, were obtained from the gorgonian coral Rumphella antipathies. The structures of 1 and 2 were elucidated by spectroscopic methods and compound 2 was found to display modest inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils at a concentration of 10 μg/mL

  10. Shot reproducibility of the self-magnetic-pinch diode at 4.5 MV

    OpenAIRE

    Nichelle Bennett; M. Dale Crain; Darryl W. Droemer; Raymond E. Gignac; Greg Lare; Isidro Molina; Robert Obregon; Chase C. Smith; Frank L. Wilkins; Dale R. Welch; Steve Cordova; Manuel L. Gallegos; Mark D. Johnston; Mark L. Kiefer; Joshua J. Leckbee

    2014-01-01

    In experiments conducted at Sandia National Laboratories’ RITS-6 accelerator, the self-magnetic-pinch diode exhibits significant shot-to-shot variability. Specifically, for identical hardware operated at the same voltage, some shots exhibit a catastrophic drop in diode impedance. A study is underway to identify sources of shot-to-shot variations which correlate with diode impedance collapse. The scope of this report is limited to data collected at 4.5-MV peak voltage and sources of variabilit...

  11. Penerapan Algoritma Decision Tree C4.5 Untuk Penilaian Rumah Tinggal

    OpenAIRE

    Setiadi, Budi

    2015-01-01

    There is still a possibility of assessment error homes as a reference value of credit, which will open opportunities for NPL. So we need a way of assessment (predictive value) is quite proportional, credible and accurate. Inaccurate predictions led to the planning of improper credit management. Prediction value of collateral house has attracted the interest of many researchers because of its importance both in theoretical andempirical.Namely C4.5 decision tree algorithm, CART and CHAID that c...

  12. Exploiting the CNC side chain in heterocyclic rearrangements: synthesis of 4(5)-acylamino-imidazoles.

    Science.gov (United States)

    Piccionello, Antonio Palumbo; Buscemi, Silvestre; Vivona, Nicolò; Pace, Andrea

    2010-08-06

    A new variation on the Boulton-Katritzky reaction is reported, namely, involving use of a CNC side chain. A novel Montmorillonite-K10 catalyzed nonreductive transamination of a 3-benzoyl-1,2,4-oxadiazole afforded a 3-(alpha-aminobenzyl)-1,2,4-oxadiazole, which was condensed with benzaldehydes to afford the corresponding imines. In the presence of strong base, these imines underwent Boulton-Katritzky-type rearrangement to afford novel 4(5)-acylaminoimidazoles.

  13. Incorporating remote sensing-based ET estimates into the Community Land Model version 4.5

    Directory of Open Access Journals (Sweden)

    D. Wang

    2017-07-01

    Full Text Available Land surface models bear substantial biases in simulating surface water and energy budgets despite the continuous development and improvement of model parameterizations. To reduce model biases, Parr et al. (2015 proposed a method incorporating satellite-based evapotranspiration (ET products into land surface models. Here we apply this bias correction method to the Community Land Model version 4.5 (CLM4.5 and test its performance over the conterminous US (CONUS. We first calibrate a relationship between the observational ET from the Global Land Evaporation Amsterdam Model (GLEAM product and the model ET from CLM4.5, and assume that this relationship holds beyond the calibration period. During the validation or application period, a simulation using the default CLM4.5 (CLM is conducted first, and its output is combined with the calibrated observational-vs.-model ET relationship to derive a corrected ET; an experiment (CLMET is then conducted in which the model-generated ET is overwritten with the corrected ET. Using the observations of ET, runoff, and soil moisture content as benchmarks, we demonstrate that CLMET greatly improves the hydrological simulations over most of the CONUS, and the improvement is stronger in the eastern CONUS than the western CONUS and is strongest over the Southeast CONUS. For any specific region, the degree of the improvement depends on whether the relationship between observational and model ET remains time-invariant (a fundamental hypothesis of the Parr et al. (2015 method and whether water is the limiting factor in places where ET is underestimated. While the bias correction method improves hydrological estimates without improving the physical parameterization of land surface models, results from this study do provide guidance for physically based model development effort.

  14. Molecular analysis of the iap gene of Listeria monocytogenes isolated from cheeses in Rio Grande do Sul, Brazil Análise molecular do gene iap de Listeria monocytogenes isoladas de queijos no Estado do Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Jozi Fagundes de Mello

    2008-03-01

    Full Text Available The polymorphic region sequences in the iap gene were analyzed in 25 strains of Listeria monocytogenes isolated from cheeses in the state of Rio Grande do Sul, and compared with reference strains. This investigation distinguished two clusters of L. monocytogenes: I (20 strains and II (5 strains.A seqüência da região polimórfica do gene iap foi analisada em 25 cepas de Listeria monocytogenes isoladas de queijo no Estado do Rio Grande do Sul e comparadas com cepas referências. Esta investigação distinguiu L. monocytogenes em dois grupos: I (20 cepas e II (5 cepas.

  15. Frequency of contamination Listeria monocytogenes of raw dried cured vacuum packed sausages

    Directory of Open Access Journals (Sweden)

    Hristo Daskalov

    2014-03-01

    Full Text Available The aim of this study was to collect actual data concerning the frequency of contamination with Listeria monocytogenes of some very popular in Bulgaria raw dried cured vacuum packed sausages, produced from October 2004 till May 2008. 148 vacuum-packed samples were taken from 9 different food business operators during all seasons of the year. The samples were analyzed according to USDA method for meat foods. Ten specimens were positive for presence of Listeria monocytogenes equal to 6,75% of all tested samples. In two other raw dried cured sausages L.welshimeri and L.innocua were found, but these species are not pathogenic for consumers. In the period before the official implementation of HACCP system (01.01.2006 in Bulgaria, 52 samples were examined and 5 Listeria monocytogenes isolates were found (~10%. 2,5 years after the HACCP implementation, 96 specimens from the same meat factories were tested and 5 Listeria monocytogenes isolates (5,2% were detected. Samples taken from lots, produced in winter time were contaminated with Listeria monocytogenes more often (7 of all 10 than specimens taken during other seasons. Data were discussed through the point of view of the effectiveness of hygienic practices and HACCP system application. Also, application of ‘microbiological criterion’ set in COMMISSION REGULATION (EC No 2073/2005 for ready-to-eat foods unable to support the growth of L. monocytogenes was considered.

  16. An outbreak of an unusual strain of Listeria monocytogenes infection in North-East Scotland

    Directory of Open Access Journals (Sweden)

    Emmanuel Okpo

    2015-11-01

    Full Text Available Summary: Listeria monocytogenes infection is an important cause of illness and hospitalization in vulnerable individuals. In the present study, we describe a community outbreak of Listeria monocytogenes in the North-East region of Scotland, which was epidemiologically, environmentally and microbiologically linked to a local meat product and ready-to-eat product manufacturer. Infected individuals were interviewed, and an environmental investigation was conducted. Clinical and environmental samples were tested by culture, and isolates were typed by fluorescent amplified fragment length polymorphism (fAFLP. Three cases of Listeria monocytogenes were linked geographically, had the same serotype (1/2a and were indistinguishable by fAFLP type XII.6. The human, food and environmental isolates were of the same serotype and were indistinguishable by molecular typing.This is the first community outbreak of L. monocytogenes reported in Scotland since the current outbreak surveillance was established in 1996. Epidemiological and laboratory evidence indicated poor hand hygiene, unhygienic practices and cross-contamination throughout the manufacturing process of ready-to-eat foods as a possible cause of the outbreak. More stringent control of commercial food establishments that provide ready-to-eat food and the need to advise specifically vulnerable groups, e.g., pregnant women, of the risk of L. monocytogenes in ready-to-eat food is urgently needed. Keywords: Listeria monocytogenes, Outbreak, Foodborne, Community acquired infection, Listeriosis

  17. Antimicrobial resistance of Listeria monocytogenes isolated from dairy-based food products.

    Science.gov (United States)

    Harakeh, Steve; Saleh, Imane; Zouhairi, Omar; Baydoun, Elias; Barbour, Elie; Alwan, Nisreen

    2009-06-15

    In this study Listeria monocytogenes (L. monocytogenes) was isolated from three traditionally consumed Lebanese dairy-based food products. One hundred and sixty four samples (45 samples of Baladi cheese, 36 samples of Shankleesh and 83 of Kishk) were collected from the Bekaa Valley in the Northeast region of Lebanon. Suspected Listeria colonies were selected and initially identified by using standard biochemical tests. Initial identification of the positive L. monocytogenes colonies was confirmed at the molecular level by Polymerase Chain Reaction (n=30) and the confirmed isolates were evaluated for their susceptibility to 10 commonly used antimicrobials. All of the 30 isolates were confirmed to be L. monocytogenes yielding a PCR product of approximately 660 base pairs (bp). L. monocytogenes was detected in 26.67%, 13.89% and 7.23% of the Baladi cheese, Shankleesh and Kishk samples, respectively. The highest resistance in L. monocytogenes isolates was noted against oxacillin (93.33%) followed by penicillin (90%). The results provide an indication of the contamination levels of dairy-based foods in Lebanon and highlight the emergence of multi-drug resistant Listeria in the environment.

  18. Prevalence and serotypes of Listeria monocytogenes contamination in Chinese beef processing plants.

    Science.gov (United States)

    Zhu, Lixian; Feng, Xiaohui; Zhang, Lihua; Zhu, Ruiliang; Luo, Xin

    2012-06-01

    The aim of this work was to study the epidemiology of Listeria spp., particularly Listeria monocytogenes, and to identify the serotypes present in contaminated samples from beef processing plants in China. A total of 439 samples were obtained from bovine feces, hides, and carcasses at three commercial processing plants. A standard protocol (ISO 11290-1) was followed to detect Listeria spp. and L. monocytogenes, and multiplex polymerase chain reaction was used to identify the various L. monocytogenes serotypes. The overall prevalences of Listeria spp. and L. monocytogenes were 65.6% and 26.4%, respectively, and the contamination was highest in the hide samples. The identified L. monocytogenes serotypes were 1/2c and 1/2a. The results of the current study indicate that Listeria spp. contamination is common in Chinese beef processing plants; specific measures should be taken to prevent and/or treat L. monocytogenes contamination of feces and hides in beef slaughter plants. Furthermore, because Listeria spp. contamination was found to be prevalent, it should, therefore, be studied further. The prevention of cases of sporadic listeriosis in China should also be addressed.

  19. Prevalence of Listeria monocytogenes in raw bovine milk and milk products from central highlands of Ethiopia.

    Science.gov (United States)

    Seyoum, Eyasu Tigabu; Woldetsadik, Daniel Asrat; Mekonen, Tesfu Kassa; Gezahegn, Haile Alemayehu; Gebreyes, Wondwossen Abebe

    2015-11-30

    Listeria monocytogenes is of major significance in human and veterinary medicine. Most human Listeria infections are foodborne and the association of contaminated milk and dairy produce consumption with human listeriosis is noteworthy. In Ethiopia, there is limited data regarding the prevalence of L. monocytogenes in raw bovine milk and dairy products. The aim of this study was, therefore, to determine the prevalence of L. monocytogenes in raw bovine milk and dairy produce. A total of 443 milk and milk product samples were microbiologically analyzed following methods recommended by the U.S. Food and Drug Administration Bacteriological Analytical Manual to isolate Listeria spp. The overall prevalence of Listeria spp. was 28.4% and specifically that of L. monocytogenes was 5.6%. Taking the prevalence of Listeria spp. into consideration, cheese was found to be highly contaminated at 60%, followed by pasteurized milk samples (40%), raw milk (18.9%) and yoghurt (5%). Considering the prevalence of Listeria monocytogenes only, raw milk had the lowest contamination while cheese had the highest, followed by pasteurized milk and yoghurt. Raw milk and milk products produced in urban and peri-urban areas of central Ethiopia were contaminated with pathogenic bacteria, L. monocytogenes. The detection of this pathogen in raw milk and milk products warrants an urgent regulatory mechanism to be put in place and also the potential role of milk processing plants in the contamination of dairy products should be investigated.

  20. Phenotypic and Genotypic Characteristics of Listeria monocytogenes Isolated From Dairy and Meat Products

    Directory of Open Access Journals (Sweden)

    Bahador

    2015-08-01

    Full Text Available Background Listeria monocytogenes is a foodborne pathogen and a serious threat to the public health in the world. Consumption of traditional foods such as dairy and meat products can be a major reason for relative abundance and isolation of these bacteria. Objectives The purpose of this study was to determine the phenotypic and genotypic characteristics of L. monocytogenes strains isolated from dairy and meat products. Materials and Methods A total of 317 dairy products and meat-processed samples were collected. Antibiotic susceptibility test was performed on each sample by the disk diffusion method (Kirby Bauer. Five reference loci were used for typing of L. monocytogenes strains by MLVA (Multiple Locus VNTR Analysis Technique. Results A total of 24 L. monocytogenes isolates were collected from the dairy and meat products. Resistance of isolated L. monocytogenes strains to penicillin G were 54.54% (from dairy products and 46.15% (from processed meat. Genetic relatedness of isolates were assessed by MLVA. Out of 13 different types, type 2 with 6 strains and type 3 with 4 strains, were the most common types. Conclusions MLVA analysis showed that samples obtained from different sources could have similar genetic profile. As a result, administration of penicillin in patients with listeriosis (especially pregnant women and antibiotic susceptibility test are recommended. The fast and accurate methods such as MLVA for tracking of pollution sources of L. monocytogenes are recommended during outbreaks.

  1. Listeria monocytogenes infection of HD11, chicken macrophage-like cells.

    Science.gov (United States)

    Jarvis, N A; Donaldson, J R; O'Bryan, C A; Ricke, S C; Crandall, P G

    2017-04-01

    Listeria monocytogenes can be carried by and infect poultry, although the clinical disease in birds is rare. Escape from macrophage phagocytosis is a key step in pathogenesis for L. monocytogenes. Therefore, we investigated the infection of the chicken macrophage-like cell line HD11 with 2 strains of L. monocytogenes EGD-e and Scott A. After infection, L. monocytogenes was quantified by spread plating and HD11 was quantified with trypan blue exclusion stain before enumeration. The standard macrophage killing protocols require washing the cell monolayers 3 times with PBS, which was found to negatively influence HD11 monolayers. Maximum bacterial densities within macrophages were not different between the 2 Listeria strains. HD11 required more than 11 h to effectively reduce intracellular L. monocytogenes Scott A, and Scott A was more susceptible to HD11 killing than EGD-e. It appears that Listeria infection initially causes attenuation of HD11 growth, and infected HD11 cells do not begin to lyse until at least 11 h post infection. These results suggest that there are subtle strain to strain differences in response to HD11 macrophage phagocytosis. The long lead-time required for HD11 to kill L. monocytogenes cells means that there is sufficient time available for chicken macrophages to circulate in the blood and transfer the intracellular Listeria to multiple tissues. © 2016 Poultry Science Association Inc.

  2. Measurement and correlation of the solubility of 2,3,4,5-tetrabromothiophene in different solvents

    International Nuclear Information System (INIS)

    Wang, Kai; Hu, Yonghong; Yang, Wenge; Guo, Song; Shi, Ying

    2012-01-01

    Highlights: ► The solubility of tetrabromothiophene in different solvents was investigated. ► The modified Apelblat equation was more accurate than the van’t Hoff equation and the λh equation. ► Ethyl acetate showed the potential as a better recrystallization solvent to replace trichloromethane. ► The solution process in the selected solvents was endothermic and nonspontaneous. - Abstract: The solubility of 2,3,4,5-tetrabromothiophene were measured in methanol, ethanol, propan-1-ol, butan-1-ol, toluene, ethyl formate, ethyl acetate, trichloromethane and oxolane within the temperature range between 278.05 K and 325.15 K under atmospheric pressure by gravimetric method. The solubility of 2,3,4,5-tetrabromothiophene in those selected solvents increased with increasing temperature. The solubility data were correlated with the van’t Hoff equation, the modified Apelblat equation and the λh equation. The thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van’t Hoff analysis and the Gibbs equation. The experimental results showed that ethyl acetate had the potential as a better solvent in the re-crystallization process of 2,3,4,5-tetrabromothiophene.

  3. The 4.5K refrigerators for the LHC are all present and correct!

    CERN Document Server

    2004-01-01

    Acceptance procedures for the last of the LHC 4.5 K refrigerators have been completed at Point 6. All that now remains to be done, to have the LHC refrigeration system ready by the end of 2005, is to upgrade the refrigerators recovered from LEP and install the 1.8 K cooling system. By now you will be well aware that the LHC's superconducting magnets cannot operate unless they are cooled to 1.8 K (-271°C) (see Bulletin 13-14/2002). Eight 4.5 K refrigerators, one for each sector of the LHC, are required to achieve this. In December last year the last of these refrigerators, specially designed for the LHC, was accepted at Point 6. "It is a big step forwards for the LHC's refrigeration system, as it takes its cooling capacity at 4.5 K to 140 kW, that is to say almost 40,000 litres of liquid helium per hour, a capacity never previously attained. The progress achieved since the days of LEP is impressive, particularly if one bears in mind the extent of the infrastructure required, " (see...

  4. Influences of Gd on the microstructure and strength of Mg-4.5Zn alloy

    International Nuclear Information System (INIS)

    Yang Jie; Xiao Wenlong; Wang Lidong; Wu Yaoming; Wang Limin; Zhang Hongjie

    2008-01-01

    Microstructure and mechanical properties of peak-aged Mg-4.5Zn-xGd (x 0, 0.5, 1.0 and 1.5 wt.%) alloys have been investigated. The results showed that the grain size of the alloys was refined gradually with increasing Gd. Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases were found in the Gd-containing alloys. The strengths were greatly improved with Gd additions, and the highest strength level was obtained in the Mg-4.5Zn-1.5Gd alloy, in which the ultimate tensile strength and yield strength were 231 MPa and 113 MPa, respectively. Through comparing with the Mg-4.5Zn alloy, the increments of ultimate tensile strength and yield strength were 22 MPa and 56 MPa, respectively. The improved strength was mainly correlated to the grain refining effect, the strengthening effect of the Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases and also the hardening effect of the solutioned Gd atoms

  5. PCA based feature reduction to improve the accuracy of decision tree c4.5 classification

    Science.gov (United States)

    Nasution, M. Z. F.; Sitompul, O. S.; Ramli, M.

    2018-03-01

    Splitting attribute is a major process in Decision Tree C4.5 classification. However, this process does not give a significant impact on the establishment of the decision tree in terms of removing irrelevant features. It is a major problem in decision tree classification process called over-fitting resulting from noisy data and irrelevant features. In turns, over-fitting creates misclassification and data imbalance. Many algorithms have been proposed to overcome misclassification and overfitting on classifications Decision Tree C4.5. Feature reduction is one of important issues in classification model which is intended to remove irrelevant data in order to improve accuracy. The feature reduction framework is used to simplify high dimensional data to low dimensional data with non-correlated attributes. In this research, we proposed a framework for selecting relevant and non-correlated feature subsets. We consider principal component analysis (PCA) for feature reduction to perform non-correlated feature selection and Decision Tree C4.5 algorithm for the classification. From the experiments conducted using available data sets from UCI Cervical cancer data set repository with 858 instances and 36 attributes, we evaluated the performance of our framework based on accuracy, specificity and precision. Experimental results show that our proposed framework is robust to enhance classification accuracy with 90.70% accuracy rates.

  6. Challenges experienced by South Africa in attaining Millennium Development Goals 4, 5 and 6

    Directory of Open Access Journals (Sweden)

    Fhumulani M. Mulaudzi

    2016-05-01

    Full Text Available Background: Despite progress made by other countries worldwide in achieving Millennium Development Goals (MDGs 4, 5 and 6, South Africa is experiencing a challenge in attaining positive outcomes for these goals. Objective and setting: To describe the challenges experienced by South Africa regarding the successful implementation of MDGs 4, 5 and 6. Methods: An integrative literature review was used to identify and synthesise various streams of literature on the challenges experienced by South Africa in attaining MDGs 4, 5 and 6. Results: The integrative review revealed the following themes: (1 interventions related to child mortality reduction, (2 implementation of maternal mortality reduction strategies, and (3 identified barriers to zero HIV and TB infections and management. Conclusion: It is recommended that poverty relief mechanisms be intensified to improve the socio-economic status of women. There is a need for sectoral planning towards maternal health, and training of healthcare workers should emphasise the reduction of maternal deaths. Programmes addressing the reduction of maternal and child mortality rates, HIV, STIs and TB need to be put in place. Keywords: Millennium Development Goals; maternal and child morbidity and mortality; HIV and AIDS; STI and TB

  7. Implementation of Data Mining to Analyze Drug Cases Using C4.5 Decision Tree

    Science.gov (United States)

    Wahyuni, Sri

    2018-03-01

    Data mining was the process of finding useful information from a large set of databases. One of the existing techniques in data mining was classification. The method used was decision tree method and algorithm used was C4.5 algorithm. The decision tree method was a method that transformed a very large fact into a decision tree which was presenting the rules. Decision tree method was useful for exploring data, as well as finding a hidden relationship between a number of potential input variables with a target variable. The decision tree of the C4.5 algorithm was constructed with several stages including the selection of attributes as roots, created a branch for each value and divided the case into the branch. These stages would be repeated for each branch until all the cases on the branch had the same class. From the solution of the decision tree there would be some rules of a case. In this case the researcher classified the data of prisoners at Labuhan Deli prison to know the factors of detainees committing criminal acts of drugs. By applying this C4.5 algorithm, then the knowledge was obtained as information to minimize the criminal acts of drugs. From the findings of the research, it was found that the most influential factor of the detainee committed the criminal act of drugs was from the address variable.

  8. The co-chaperones Fkbp4/5 control Argonaute2 expression and facilitate RISC assembly.

    Science.gov (United States)

    Martinez, Natalia J; Chang, Hao-Ming; Borrajo, Jacob de Riba; Gregory, Richard I

    2013-11-01

    Argonaute2 (Ago2) protein and associated microRNAs (miRNAs) or small interfering RNAs (siRNAs) form the RNA-induced silencing complex (RISC) for target messenger RNA cleavage and post-transcriptional gene silencing. Although Ago2 is essential for RISC activity, the mechanism of RISC assembly is not well understood, and factors controlling Ago2 protein expression are largely unknown. A role for the Hsc70/Hsp90 chaperone complex in loading small RNA duplexes into the RISC has been demonstrated in cell extracts, and unloaded Ago2 is unstable and degraded by the lysosome in mammalian cells. Here we identify the co-chaperones Fkbp4 and Fkbp5 as Ago2-associated proteins in mouse embryonic stem cells. Pharmacological inhibition of this interaction using FK506 or siRNA-mediated Fkbp4/5 depletion leads to decreased Ago2 protein levels. We find FK506 treatment inhibits, whereas Fkbp4/5 overexpression promotes, miRNA-mediated stabilization of Ago2 expression. Simultaneous treatment with a lysosome inhibitor revealed the accumulation of unloaded Ago2 complexes in FK506-treated cells. We find that, consistent with unloaded miRNAs being unstable, FK506 treatment also affects miRNA abundance, particularly nascent miRNAs. Our results support a role for Fkbp4/5 in RISC assembly.

  9. Factors associated with Listeria monocytogenes contamination of cold-smoked pork products produced in Latvia and Lithuania.

    OpenAIRE

    Berzins,-A; Horman,-A; Lunden,-J; Korkeala,-H

    2007-01-01

    A total of 312 samples of sliced, vacuum packaged, cold-smoked pork from 15 meat processing plants in Latvia and Lithuania, obtained over a 15-month period from 2003 until 2004, were analyzed for the presence of Listeria monocytogenes at the end of their shelf-life. Overall, 120 samples (38%) tested positive for L. monocytogenes. Despite the long storing period, the levels of L. monocytogenes in cold-smoked pork products were low. Manufacturing processes were studied at seven meat processing ...

  10. Spontaneous Bacterial Peritonitis Caused by Infection with Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Michael Vincent F. Tablang

    2008-11-01

    Full Text Available Spontaneous bacterial peritonitis is a severe and life-threatening complication in patients with ascites caused by advanced liver disease. The organisms most commonly involved are coliform bacteria and third-generation cephalosporins are the empiric antibiotics of choice. This is an uncommon case of spontaneous bacterial peritonitis caused by Listeria monocytogenes in a female patient with liver cirrhosis from autoimmune hepatitis. She did not improve with ceftriaxone and her course was complicated by hepatic encephalopathy, seizures and multi-organ failure. This case emphasizes that a high index of suspicion should be maintained for timely diagnosis and treatment. Listerial peritonitis should be suspected in patients with end-stage liver disease and inadequate response to conventional antibiotics within 48–72 h. Ampicillin/sulbactam should be initiated while awaiting results of ascitic fluid or blood culture.

  11. Modeling the survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium during fermentation, drying, and storage of soudjouk-style fermented sausage.

    Science.gov (United States)

    Hwang, Cheng-An; Porto-Fett, Anna C S; Juneja, Vijay K; Ingham, Steven C; Ingham, Barbara H; Luchansky, John B

    2009-02-28

    This study quantified and modeled the survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Typhimurium in soudjouk-style fermented sausage during fermentation, drying, and storage. Batter prepared from ground beef (20% fat), seasonings, starter culture, and dextrose was separately inoculated with a multi-strain mixture of each pathogen to an initial inoculum of ca. 6.5 log(10) CFU/g in the batter. The sausages were subsequently fermented at 24 degrees C with a relative humidity (RH) of 90% to 95% for 3 to 5 days to ca. pH 5.2, pH 4.9 or pH 4.6, then dried at 22 degrees C to a(w) 0.92, a(w) 0.89, or a(w) 0.86, respectively, and then stored at 4, 21, or 30 degrees C for up to 60 days. Lethality of the three pathogens was modeled as a function of pH, a(w) and/or storage temperature. During fermentation to pH 5.2 to pH 4.6, cell reductions ranged from 0 to 0.9 log(10) CFU/g for E. coli O157:H7, 0.1 to 0.5 log(10) CFU/g for L. monocytogenes, and 0 to 2.2 log(10) CFU/g for S. Typhimurium. Subsequent drying of sausages of pH 5.2 to pH 4.6 at 22 degrees C with 80% to 85% RH for 3 to 7 days to a(w) of 0.92 to a(w) 0.86 resulted in additional reductions that ranged from 0 to 3.5 log(10) CFU/g for E. coli O157:H7, 0 to 0.4 log(10) CFU/g for L. monocytogenes, and 0.3 to 2.4 log(10) CFU/g for S. Typhimurium. During storage at 4, 21, or 30 degrees C the reduction rates of the three pathogens were generally higher (pfermentation, drying, and storage. The applicability of the resulting models for fermented sausage was evaluated by comparing model predictions with published data. Pathogen reductions estimated by the models for E. coli O157:H7 and S. Typhimurium were comparable to 67% and 73% of published data, respectively. Due to limited published data for L. monocytogenes, the models for L. monocytogenes would need additional validations. Results of pathogen reductions from this study may be used as a reference to assist manufacturers of soudjouk

  12. Individual and combined efficacies of mild heat and ultraviolet-c radiation against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in coconut liquid endosperm.

    Science.gov (United States)

    Gabriel, Alonzo A; Ostonal, Jeffrey M; Cristobal, Jannelle O; Pagal, Gladess A; Armada, John Vincent E

    2018-07-20

    This study determined the inactivation kinetic parameters of selected pathogens in heat, ultraviolet-C and combined heat-UV-C treated coconut liquid endosperm. Separate cocktails of Escherichia coli O157:H7, Salmonella enterica serovars, and Listeria monocytogenes strains were inoculated into coconut liquid endosperm (pH 5.15, TSS 4.4 o Bx, TA 0.062% malic acid, extinction coefficient (ε) at 254 nm of 0.0154 cm -1 ) for inactivation studies. Result showed that all organisms generally exhibited a log-linear heat inactivation behavior (R 2 0.81-0.99). The E. coli O157:H7 cocktail (D 55  = 19.75 min, D 57  = 10.79 min, D 60  = 3.38 min, and D 63  = 0.46 min) was found to be significantly more resistant (P > 0.05) than the tested cocktail of L. monocytogenes (D 55  = 11.68 min, D 57  = 4.53 min, D 60  = 1.82 min and D 63  = 0.26 min) and S. enterica cocktail (D 55  = 3.08 min, D 57  = 2.60 min, D 60  = 0.89 min and D 63  = 0.25 min). Despite the differences in D T values, computed z values for L. monocytogenes cocktail (5.12 ± 0.43 °C) and E. coli O157:H7 cocktail (4.95 ± 0.12 °C) were not significantly different (P > 0.05), but were both significantly (P C). All test organisms also exhibited a generally log-linear UV-C inactivation behavior (R 2 0.90-0.99) with E. coli O157:H7 cocktail (D UV-C  = 25.26 mJ/cm 2 ) demonstrating greatest resistance to UV-C than S. enterica (D UV-C  = 24.65 mJ/cm 2 ) and L. monocytogenes (D UV-C  = 17.30 mJ/cm 2 ) cocktails. The D 55 values of each organism cocktail were used to calculate for the 3-log reduction heating process schedules, during which UV-C treatments were simultaneously applied. Lethal rates (F values) calculations in the combined processes revealed that within the 3-log reduction heating processes, co-exposure of UV-C resulted in 5.62 to 6.20 log reductions in the test organism populations. Heating

  13. The Effect of Oxygen on Bile Resistance in Listeria monocytogenes

    Science.gov (United States)

    Wright, Morgan L; Pendarvis, Ken; Nanduri, Bindu; Edelmann, Mariola J; Jenkins, Haley N; Reddy, Joseph S; Wilson, Jessica G; Ding, Xuan; Broadway, Paul R; Ammari, Mais G; Paul, Oindrila; Roberts, Brandy; Donaldson, Janet R

    2016-01-01

    Listeria monocytogenes is a Gram-positive facultative anaerobe that is the causative agent of the disease listeriosis. The infectious ability of this bacterium is dependent upon resistance to stressors encountered within the gastrointestinal tract, including bile. Previous studies have indicated bile salt hydrolase activity increases under anaerobic conditions, suggesting anaerobic conditions influence stress responses. Therefore, the goal of this study was to determine if reduced oxygen availability increased bile resistance of L. monocytogenes. Four strains representing three serovars were evaluated for changes in viability and proteome expression following exposure to bile in aerobic or anaerobic conditions. Viability for F2365 (serovar 4b), EGD-e (serovar 1/2a), and 10403S (serovar 1/2a) increased following exposure to 10% porcine bile under anaerobic conditions (P 0.05) in bile resistance between aerobic and anaerobic conditions, indicating that oxygen availability does not influence resistance in this strain. The proteomic analysis indicated F2365 and EGD-e had an increased expression of proteins associated with cell envelope and membrane bioenergetics under anaerobic conditions, including thioredoxin-disulfide reductase and cell division proteins. Interestingly, HCC23 had an increase in several dehydrogenases following exposure to bile under aerobic conditions, suggesting that the NADH:NAD+ is altered and may impact bile resistance. Variations were observed in the expression of the cell shape proteins between strains, which corresponded to morphological differences observed by scanning electron microscopy. These data indicate that oxygen availability influences bile resistance. Further research is needed to decipher how these changes in metabolism impact pathogenicity in vivo and also the impact that this has on susceptibility of a host to listeriosis. PMID:27274623

  14. Dephosphorylation Pathway of D-myo-Inositol 1,4,5-trisphosphate in the Unicellular Green Alga Chlamydomonas eugametos

    NARCIS (Netherlands)

    Klerk, Hans; Himbergen, John A.J. van; Musgrave, Alan; Haastert, Peter J.M. van; Ende, Herman van den

    In vitro dephosphorylation of D-myo-inositol 1,4,5-trisphosphate [Ins(l,4,5)P-3] by vegetative cells, gametes and zygotes of the green alga Chlamydomonas eugametos was studied using a soluble cell fraction as enzyme source and labelled Ins(1,4,5)P-3 as substrate. This compound was dephosphorylated

  15. Listeria monocytogenes Meningitis in an Immunosuppressed Patient with Autoimmune Hepatitis and IgG4 Subclass Deficiency

    DEFF Research Database (Denmark)

    Gaini, Shahin

    2015-01-01

    A 51-year-old Caucasian woman with Listeria monocytogenes meningitis was treated and discharged after an uncomplicated course. Her medical history included immunosuppressive treatment with prednisolone and azathioprine for autoimmune hepatitis. A diagnostic work-up after the meningitis episode...... revealed that she had low levels of the IgG4 subclass. To our knowledge, this is the first case report describing a possible association between autoimmune hepatitis and the occurrence of Listeria monocytogenes meningitis, describing a possible association between Listeria monocytogenes meningitis...... and deficiency of the IgG4 subclass and finally describing a possible association between Listeria monocytogenes meningitis and immunosuppressive therapy with prednisolone and azathioprine....

  16. Symptomatic hydrocephalus in a newborn infected with listeria monocytogenes Hidrocefalia sintomática em um recém-nascido infectado com Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Analía L. Laciar

    2000-03-01

    Full Text Available Central nervous system infections caused by Listeria monocytogenes produce a wide range of clinical symptoms which include cerebral abscesses, meningitis and nonmeningitic parenchymal cerebritis. A case study is presented of early listeriosis with signs of meningitis accompanied with septicemia and complicated with severe hydrocephalus.As infecções do sistema nervoso central produzidas por Listeria monocytogenes provocam una grande variedade de sintomas clínicos que incluem abscessos cerebrais, meningites e cerebrites parenquimáticas não meningíticas. Apresenta-se um caso de listeriose precoce com sinais de meningite acompanhada de septicemia e agravado com hidrocefalia grave.

  17. Fate of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during storage of fermented green table olives in brine.

    Science.gov (United States)

    Argyri, Anthoula A; Lyra, Efstathia; Panagou, Efstathios Z; Tassou, Chrysoula C

    2013-10-01

    The survival of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during the storage of fermented green table olives cv. Halkidiki in brine was studied in parallel with the evolution of lactic acid bacteria (LAB), yeasts and pH. The olives were previously fermented with a starter culture (a potential probiotic strain of Lactobacillus pentosus B281--starter process) or with the indigenous microbiota (control). After the end of fermentation, olives were placed in brine, inoculated with a cocktail of 5 strains of E. coli O157:H7, 5 strains of L. monocytogenes and 4 strains of S. Enteritidis, with a final concentration in the brine of ca. 7.0 log CFU/ml, and subsequently packaged in polyethylene pouches and stored at 20 °C. The population of E. coli O157:H7 reduced gradually and was detected in the brine until the 27th day of storage in both cases (i.e., starter and control process), and on olive fruits until the 19th and 16th days of storage in the starter and control process, respectively. S. Enteritidis population showed also a decrease and it was detected until the 21st day of storage in both brine and olive fruits in both cases. The population of L. monocytogenes declined during storage and it was detected until the 31st day of storage in both brine and olive fruits in both cases, showing a longer survival period in comparison to the other two studied pathogens. The presence of the potential probiotic starter did not affect the pathogen survival. The results demonstrated that even though the growth of the pathogenic strains was not supported, they may survive for a long period in a stressful environment of a fermented product with low pH value (4.2) and high salt concentration (6.0%). These results are a valuable contribution to risk assessment studies related to ready to eat foods in general. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Metabolism of inositol(1,4,5)trisphosphate by a soluble enzyme fraction from pea (Pisum sativum) roots

    International Nuclear Information System (INIS)

    Drobak, B.K.; Watkins, P.A.C.; Roberts, K.; Chattaway, J.A.; Dawson, A.P.

    1991-01-01

    Metabolism of the putative messenger molecule D-myo-inositol(1,4,5)trisphosphate [Ins(1,4,5)P 3 ] in plant cells has been studied using a soluble fraction from pea (pisum sativum) roots as enzyme source and [5- 32 P]Ins(1,4,5)P 3 and [2- 3 H]Ins(1,4,5)P 3 as tracers. Ins(1,4,5)P 3 was rapidly converted into both lower and higher inositol phosphates. The major dephosphorylation product was inositol (4,5) bisphosphate [Ins(4,5)P 2 ] whereas inositol(1,4)bisphosphate [Ins(1,4)P 2 ] was only present in very small quantities throughout a 15 minute incubation period. In addition to these compounds, small amounts of nine other metabolites were produced including inositol and inositol(1,4,5,X)P 4 . Dephosphorylation of Ins(1,4,5)P 3 to Ins(4,5)P 2 was dependent on Ins(1,4,5)P 3 concentration and was partially inhibited by the phosphohydrolase inhibitors 2,3-diphosphoglycerate, glucose 6-phosphate, and p-nitrophenylphosphate. Conversion of Ins(1,4,5)P 3 to Ins(4,5)P 2 and Ins(1,4,5,X)P 4 was inhibited by 55 micromolar Ca 2+ . This study demonstrates that enzymes are present in plant tissues which are capable of rapidly converting Ins(1,4,5)P 3 and that pathways of inositol phosphate metabolism exist which may prove to be unique to the plant kingdom

  19. [Inoculation experiments of Cistanche tubulosa on 8 introduced Tamarix species].

    Science.gov (United States)

    Yang, Tai-Xin; Lu, Yue-Xia; Zhang, Xi-Huan; Cai, Jing-Zhu; Zhao, Yu-Xin

    2007-10-01

    To analyze the inoculation ratio and echinacoside content of Cistanche tubulosa and provide theoretical basis for Tamarix introduction, resource protection and screening of C. tubulosa. 8 Tamarix species were introduced in the North China Plain and inoculation of C. tubulosa was conducted on all species. Phenylethanoid glycosides fingerprinting and echinacoside content of C. tubulosa were analyzed by using HPLC. The adaptability of 8 Tamarix species were significantly different, phenylethanoid glycosides component of C. tubulosa on T. gansuensis and T. austromongolica were basically identical in contrast to T. chinensis, echinacoside content showed no obvious difference in C. tubulosa plant growing 4 months. T. gansuensis and T. Austromongolica are suitable for the host introduction plant of C. tubulosa resource protection and screening in North China Plain.

  20. Inoculating against eyewitness suggestibility via interpolated verbatim vs. gist testing.

    Science.gov (United States)

    Pansky, Ainat; Tenenboim, Einat

    2011-01-01

    In real-life situations, eyewitnesses often have control over the level of generality in which they choose to report event information. In the present study, we adopted an early-intervention approach to investigate to what extent eyewitness memory may be inoculated against suggestibility, following two different levels of interpolated reporting: verbatim and gist. After viewing a target event, participants responded to interpolated questions that required reporting of target details at either the verbatim or the gist level. After 48 hr, both groups of participants were misled about half of the target details and were finally tested for verbatim memory of all the details. The findings were consistent with our predictions: Whereas verbatim testing was successful in completely inoculating against suggestibility, gist testing did not reduce it whatsoever. These findings are particularly interesting in light of the comparable testing effects found for these two modes of interpolated testing.