The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Ivan Leguerinel - One of the best experts on this subject based on the ideXlab platform.
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Knowledge of the physiology of Spore-Forming Bacteria can explain the origin of spores in the food environment.
Research in Microbiology, 2016Co-Authors: Emilie Gauvry, Ivan Leguerinel, Olivier Couvert, Florence Postollec, Anne Gabrielle Mathot, Véronique Broussolle, Louis CorollerAbstract:Abstract Spore-Forming Bacteria are able to grow under a wide range of environmental conditions, to form biofilms and to differentiate into resistant forms: spores. This resistant form allows their dissemination in the environment; consequently, they may contaminate raw materials. Sporulation can occur all along the food chain, in raw materials, but also in food processes, leading to an increase in food contamination. However, the problem of sporulation during food processing is poorly addressed and sporulation niches are difficult to identify from the farm to the fork. Sporulation is a survival strategy. Some environmental factors are required to trigger this differentiation process and others act by modulating it. The efficiency of sporulation is the result of the combined effects of these two types of factors on vegetative cell metabolism. This paper aims to explain and help identify sporulation niches in the food chain, based on features of spore-former physiology.
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Identification, heat resistance and growth potential of mesophilic Spore-Forming Bacteria isolated from Algerian retail packaged couscous
Food Control, 2014Co-Authors: Mohammed Ziane, Patrick Le Chevalier, Boumediene Moussa-boudjemaa, Olivier Couvert, Noemie Desriac, Ivan LeguerinelAbstract:Abstract Aims In this study, species taxonomy, heat resistance and growth potential of mesophilic aerobic Spore-Forming Bacillus strains isolated from commercially available couscous were determined. Methods and results Aerobic Spore-Forming Bacteria were isolated from three Algerian retail couscous samples heated at 80 °C for 10 min. Plate counting of Spore-Forming Bacteria showed a mean concentration of 20 CFU/g. By monitoring 16S gene sequencing, ten Bacillus strains were identified, belonging to 3 different species: five Bacillus licheniformis strains, four Bacillus cereus group strains sensu lato and one Bacillus subtilis strain. According to the panC gene sequencing, the four B. cereus strains were assigned to the group IV (mesophilic and heat resistant group, associated with cases of foodborne illness). B. cereus cells growth kinetics in moistened couscous semolina showed a specific growth rate of 0.33 h −1 at 30 °C, confirming their growth ability in this media. The heat resistance ( δ value i.e. the first decimal reduction time) and heat sensitivity ( z T values i.e. the temperature increase leading a ten-fold reduction of the δ value) of spores of B. cereus and B. subtilis strains were determined using Weibull and Bigelow models, respectively. δ 100 °C values are ranged from 0.14 to 7.90 min and estimated z T values ranged from 7.52 °C to 10.38 °C. Moreover, the estimate four decimal reduction times at 90 °C ( t 4D) of spores of isolated B. cereus strains were from 0.58 h to 3.73 h. Conclusions B. cereus strains isolated from retail packaged couscous semolina are resistant to heat treatment both during the industrial food process and can easily grow in moistened couscous semolina. These observations could explain numerous B. cereus outbreaks associated with couscous semolina consumption.
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Identification, heat resistance and growth potential of mesophilic Spore-Forming Bacteria isolated from Algerian retail packaged couscous
Food Control, 2014Co-Authors: Mohammed Ziane, Patrick Le Chevalier, Boumediene Moussa-boudjemaa, Olivier Couvert, Noemie Desriac, Ivan LeguerinelAbstract:In this study, species taxonomy, heat resistance and growth potential of mesophilic aerobic Spore-Forming Bacillus strains isolated from commercially available couscous were determined. Aerobic Spore-Forming Bacteria were isolated from three Algerian retail couscous samples heated at 80 °C for 10 min. Plate counting of Spore-Forming Bacteria showed a mean concentration of 20 CFU/g. By monitoring 16S gene sequencing, ten Bacillus strains were identified, belonging to 3 different species: five Bacillus licheniformis strains, four Bacillus cereus group strains sensu lato and one Bacillus subtilis strain. According to the panC gene sequencing, the four B. cereus strains were assigned to the group IV (mesophilic and heat resistant group, associated with cases of foodborne illness). B. cereus cells growth kinetics in moistened couscous semolina showed a specific growth rate of 0.33 h−1 at 30 °C, confirming their growth ability in this media. The heat resistance (δ value i.e. the first decimal reduction time) and heat sensitivity (zT values i.e. the temperature increase leading a ten-fold reduction of the δ value) of spores of B. cereus and B. subtilis strains were determined using Weibull and Bigelow models, respectively. δ100 °C values are ranged from 0.14 to 7.90 min and estimated zT values ranged from 7.52 °C to 10.38 °C. Moreover, the estimate four decimal reduction times at 90 °C (t4D) of spores of isolated B. cereus strains were from 0.58 h to 3.73 h. B. cereus strains isolated from retail packaged couscous semolina are resistant to heat treatment both during the industrial food process and can easily grow in moistened couscous semolina. These observations could explain numerous B. cereus outbreaks associated with couscous semolina consumption.
Guoqing He - One of the best experts on this subject based on the ideXlab platform.
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Microbiota of milk powders and the heat resistance and spoilage potential of aerobic Spore-Forming Bacteria
International Dairy Journal, 2018Co-Authors: Faizan A. Sadiq, Steve Flint, Guoqing HeAbstract:Abstract Aerobic spore forming Bacteria are a concern to the dairy industry because of their ability to produce heat-resistant spores and heat-stable enzymes; The presence of spores in end products results in non-compliance with spore content specifications and the enzymes may withstand all heat treatments applied during the manufacture of milk powders, causing severe quality defects in the final product leading to reduced shelf life. The factors conferring heat resistance to Bacterial spores are related to the spore's macromolecular structure, also to a mobile genetic element involved in the heat resistance of spores. A greater understanding of the microbiota of milk powders, its heat resistance and spoilage potential is needed to develop better strategies to fight with these Spore-Forming Bacteria. Therefore, the current status of the microbiota of milk powders is reviewed. Furthermore, heat resistance and spoilage potential of major milk powder contaminants and the factors affecting these properties are discussed in detail.
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the heat resistance and spoilage potential of aerobic mesophilic and thermophilic spore forming Bacteria isolated from chinese milk powders
International Journal of Food Microbiology, 2016Co-Authors: Faizan A. Sadiq, Steve Flint, Yun Li, Guohua Zhang, Lei Yuan, Guoqing HeAbstract:Abstract The propensity for aerobic bacilli and allied genera to produce highly heat-resistant spores and thermally stable spoilage enzymes are major bacteriological issues faced by the dairy industry. Most of the enzymes are able to survive any heat treatment applied during the manufacture of milk powders and have the potential to remain active in milk powders and other dairy products during storage, and may explain some of the sensory and functionality defects reported in dairy products. Despite many reports on the occurrence of Spore-Forming Bacteria in dairy products, knowledge about food quality related properties of many aerobic sporeformers is still scarce. Therefore, the aim of this study was to determine thermal resistance and spoilage potential of a large pool of mesophilic and thermophilic sporeformers, representing 738 isolates and 31 different RAPD groups, recently isolated from Chinese milk powders. Spore formers producing highly heat resistant spores (surviving 125 °C for 30 min) included 2 thermophiles ( Geobacillus thermoleovorans group and Geobacillus stearothermophilus ) and one mesophilic species ( Brevibacillus brevis ). Paenibacillus macerans showed the highest proteolytic activity followed by members of the Bacillus cereus group, Br. brevis , Bacillus subtilis , G. thermoleovorans group and Virgibacillus proomii . The highest lipase producing strains belonged to Bacillus licheniformis . Phospholipase activity was only shown by members of the B. cereus group and Brevibacillus parabrevis . Ten strains showed positive β -galactosidase activity, while, 4 strains showed positive haemolytic activity. B. licheniformis strains, despite belonging to one RAPD group or sub-group showed markedly different phenotypic characters which support the previous findings of heterogeneity in RAPD-based B. licheniformis groups. The results of this study will broaden the knowledge about the spoilage potential and thermal resistance of many strains of dairy origin.
Mohammed Ziane - One of the best experts on this subject based on the ideXlab platform.
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Identification, heat resistance and growth potential of mesophilic Spore-Forming Bacteria isolated from Algerian retail packaged couscous
Food Control, 2014Co-Authors: Mohammed Ziane, Patrick Le Chevalier, Boumediene Moussa-boudjemaa, Olivier Couvert, Noemie Desriac, Ivan LeguerinelAbstract:Abstract Aims In this study, species taxonomy, heat resistance and growth potential of mesophilic aerobic Spore-Forming Bacillus strains isolated from commercially available couscous were determined. Methods and results Aerobic Spore-Forming Bacteria were isolated from three Algerian retail couscous samples heated at 80 °C for 10 min. Plate counting of Spore-Forming Bacteria showed a mean concentration of 20 CFU/g. By monitoring 16S gene sequencing, ten Bacillus strains were identified, belonging to 3 different species: five Bacillus licheniformis strains, four Bacillus cereus group strains sensu lato and one Bacillus subtilis strain. According to the panC gene sequencing, the four B. cereus strains were assigned to the group IV (mesophilic and heat resistant group, associated with cases of foodborne illness). B. cereus cells growth kinetics in moistened couscous semolina showed a specific growth rate of 0.33 h −1 at 30 °C, confirming their growth ability in this media. The heat resistance ( δ value i.e. the first decimal reduction time) and heat sensitivity ( z T values i.e. the temperature increase leading a ten-fold reduction of the δ value) of spores of B. cereus and B. subtilis strains were determined using Weibull and Bigelow models, respectively. δ 100 °C values are ranged from 0.14 to 7.90 min and estimated z T values ranged from 7.52 °C to 10.38 °C. Moreover, the estimate four decimal reduction times at 90 °C ( t 4D) of spores of isolated B. cereus strains were from 0.58 h to 3.73 h. Conclusions B. cereus strains isolated from retail packaged couscous semolina are resistant to heat treatment both during the industrial food process and can easily grow in moistened couscous semolina. These observations could explain numerous B. cereus outbreaks associated with couscous semolina consumption.
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Identification, heat resistance and growth potential of mesophilic Spore-Forming Bacteria isolated from Algerian retail packaged couscous
Food Control, 2014Co-Authors: Mohammed Ziane, Patrick Le Chevalier, Boumediene Moussa-boudjemaa, Olivier Couvert, Noemie Desriac, Ivan LeguerinelAbstract:In this study, species taxonomy, heat resistance and growth potential of mesophilic aerobic Spore-Forming Bacillus strains isolated from commercially available couscous were determined. Aerobic Spore-Forming Bacteria were isolated from three Algerian retail couscous samples heated at 80 °C for 10 min. Plate counting of Spore-Forming Bacteria showed a mean concentration of 20 CFU/g. By monitoring 16S gene sequencing, ten Bacillus strains were identified, belonging to 3 different species: five Bacillus licheniformis strains, four Bacillus cereus group strains sensu lato and one Bacillus subtilis strain. According to the panC gene sequencing, the four B. cereus strains were assigned to the group IV (mesophilic and heat resistant group, associated with cases of foodborne illness). B. cereus cells growth kinetics in moistened couscous semolina showed a specific growth rate of 0.33 h−1 at 30 °C, confirming their growth ability in this media. The heat resistance (δ value i.e. the first decimal reduction time) and heat sensitivity (zT values i.e. the temperature increase leading a ten-fold reduction of the δ value) of spores of B. cereus and B. subtilis strains were determined using Weibull and Bigelow models, respectively. δ100 °C values are ranged from 0.14 to 7.90 min and estimated zT values ranged from 7.52 °C to 10.38 °C. Moreover, the estimate four decimal reduction times at 90 °C (t4D) of spores of isolated B. cereus strains were from 0.58 h to 3.73 h. B. cereus strains isolated from retail packaged couscous semolina are resistant to heat treatment both during the industrial food process and can easily grow in moistened couscous semolina. These observations could explain numerous B. cereus outbreaks associated with couscous semolina consumption.
Faizan A. Sadiq - One of the best experts on this subject based on the ideXlab platform.
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Microbiota of milk powders and the heat resistance and spoilage potential of aerobic Spore-Forming Bacteria
International Dairy Journal, 2018Co-Authors: Faizan A. Sadiq, Steve Flint, Guoqing HeAbstract:Abstract Aerobic spore forming Bacteria are a concern to the dairy industry because of their ability to produce heat-resistant spores and heat-stable enzymes; The presence of spores in end products results in non-compliance with spore content specifications and the enzymes may withstand all heat treatments applied during the manufacture of milk powders, causing severe quality defects in the final product leading to reduced shelf life. The factors conferring heat resistance to Bacterial spores are related to the spore's macromolecular structure, also to a mobile genetic element involved in the heat resistance of spores. A greater understanding of the microbiota of milk powders, its heat resistance and spoilage potential is needed to develop better strategies to fight with these Spore-Forming Bacteria. Therefore, the current status of the microbiota of milk powders is reviewed. Furthermore, heat resistance and spoilage potential of major milk powder contaminants and the factors affecting these properties are discussed in detail.
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the heat resistance and spoilage potential of aerobic mesophilic and thermophilic spore forming Bacteria isolated from chinese milk powders
International Journal of Food Microbiology, 2016Co-Authors: Faizan A. Sadiq, Steve Flint, Yun Li, Guohua Zhang, Lei Yuan, Guoqing HeAbstract:Abstract The propensity for aerobic bacilli and allied genera to produce highly heat-resistant spores and thermally stable spoilage enzymes are major bacteriological issues faced by the dairy industry. Most of the enzymes are able to survive any heat treatment applied during the manufacture of milk powders and have the potential to remain active in milk powders and other dairy products during storage, and may explain some of the sensory and functionality defects reported in dairy products. Despite many reports on the occurrence of Spore-Forming Bacteria in dairy products, knowledge about food quality related properties of many aerobic sporeformers is still scarce. Therefore, the aim of this study was to determine thermal resistance and spoilage potential of a large pool of mesophilic and thermophilic sporeformers, representing 738 isolates and 31 different RAPD groups, recently isolated from Chinese milk powders. Spore formers producing highly heat resistant spores (surviving 125 °C for 30 min) included 2 thermophiles ( Geobacillus thermoleovorans group and Geobacillus stearothermophilus ) and one mesophilic species ( Brevibacillus brevis ). Paenibacillus macerans showed the highest proteolytic activity followed by members of the Bacillus cereus group, Br. brevis , Bacillus subtilis , G. thermoleovorans group and Virgibacillus proomii . The highest lipase producing strains belonged to Bacillus licheniformis . Phospholipase activity was only shown by members of the B. cereus group and Brevibacillus parabrevis . Ten strains showed positive β -galactosidase activity, while, 4 strains showed positive haemolytic activity. B. licheniformis strains, despite belonging to one RAPD group or sub-group showed markedly different phenotypic characters which support the previous findings of heterogeneity in RAPD-based B. licheniformis groups. The results of this study will broaden the knowledge about the spoilage potential and thermal resistance of many strains of dairy origin.
Albert Bolhuis - One of the best experts on this subject based on the ideXlab platform.
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Development of a filter to prevent infections with Spore-Forming Bacteria in injecting drug users.
Harm Reduction Journal, 2016Co-Authors: Nour Alhusein, Jennifer Scott, Barbara Kasprzyk-hordern, Albert BolhuisAbstract:In heroin injectors, there have been a number of outbreaks caused by Spore-Forming Bacteria, causing serious infections such as anthrax or botulism. These are, most likely, caused by injecting contaminated heroin, and our aim was to develop a filter that efficiently removes these Bacteria and is also likely to be acceptable for use by people who inject drugs (i.e. quick, simple and not spoil the hit). A prototype filter was designed and different filter membranes were tested to assess the volume of liquid retained, filtration time and efficiency of the filter at removing Bacterial spores. Binding of active ingredients of heroin to different types of membrane filters was determined using a highly sensitive analytical chemistry technique. Heroin samples that were tested contained up to 580 Bacteria per gramme, with the majority being Bacillus spp., which are Spore-Forming soil Bacteria. To remove these Bacteria, a prototype filter was designed to fit insulin-type syringes, which are commonly used by people who inject drugs (PWIDs). Efficient filtration of heroin samples was achieved by combining a prefilter to remove particles and a 0.22 μm filter to remove Bacterial spores. The most suitable membrane was polyethersulfone (PES). This membrane had the shortest filtration time while efficiently removing Bacterial spores. No or negligible amounts of active ingredients in heroin were retained by the PES membrane. This study successfully produced a prototype filter designed to filter Bacterial spores from heroin samples. Scaled up production could produce an effective harm reduction tool, especially during outbreaks such as occurred in Europe in 2009/10 and 2012.
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Development of a filter to prevent infections with Spore-Forming Bacteria in injecting drug users
Harm Reduction Journal, 2016Co-Authors: Nour Alhusein, Barbara Kasprzyk-hordern, Jenny Scott, Albert BolhuisAbstract:Background In heroin injectors, there have been a number of outbreaks caused by Spore-Forming Bacteria, causing serious infections such as anthrax or botulism. These are, most likely, caused by injecting contaminated heroin, and our aim was to develop a filter that efficiently removes these Bacteria and is also likely to be acceptable for use by people who inject drugs (i.e. quick, simple and not spoil the hit). Methods A prototype filter was designed and different filter membranes were tested to assess the volume of liquid retained, filtration time and efficiency of the filter at removing Bacterial spores. Binding of active ingredients of heroin to different types of membrane filters was determined using a highly sensitive analytical chemistry technique. Results Heroin samples that were tested contained up to 580 Bacteria per gramme, with the majority being Bacillus spp., which are Spore-Forming soil Bacteria. To remove these Bacteria, a prototype filter was designed to fit insulin-type syringes, which are commonly used by people who inject drugs (PWIDs). Efficient filtration of heroin samples was achieved by combining a prefilter to remove particles and a 0.22 μm filter to remove Bacterial spores. The most suitable membrane was polyethersulfone (PES). This membrane had the shortest filtration time while efficiently removing Bacterial spores. No or negligible amounts of active ingredients in heroin were retained by the PES membrane. Conclusions This study successfully produced a prototype filter designed to filter Bacterial spores from heroin samples. Scaled up production could produce an effective harm reduction tool, especially during outbreaks such as occurred in Europe in 2009/10 and 2012.