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Hervé Prévost - One of the best experts on this subject based on the ideXlab platform.
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Draft Genome Sequence of Carnobacterium divergens V41, a Bacteriocin-Producing Strain
Genome Announcements, 2016Co-Authors: Benoit Remenant, M. F. Pilet, Anne Marie Revol-junelles, Hervé Prévost, Laurent Marché, Frederic Borges, Catherine Cailliez-grimal, Aurélie Lajus, Claudine Médigue, Monique ZagorecAbstract:In this study, we present the draft genome sequence of Carnobacterium divergens V41. This strain was previously reported as producing divercin V41, a bacteriocin of interest for food biopreservation. Its genome revealed also the presence of a gene cluster putatively involved in polyketide production, which is unique in lactic acid bacteria.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, twelve factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulphate, manganese sulphate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5-8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2-20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 x 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g-1) during five weeks of vacuum storage at 4° and 8°C.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, 12 factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulfate, manganese sulfate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5–8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2–20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 × 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g−1) during 5 weeks of vacuum storage at 4 and 8°C.
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Insights into structure-activity relationships in the C-terminal region of divercin V41, a class IIa bacteriocin with high-level antilisterial activity.
Applied and Environmental Microbiology, 2009Co-Authors: Jitka Rihakova, Hervé Prévost, Vanessa W Petit, Katerina Demnerova, Sylvie Rebuffat, Djamel DriderAbstract:Divercin V41 (DvnV41) is a class IIa bacteriocin with potent antilisterial activity isolated from Carnobacterium divergens V41. Previously, we expressed from a synthetic gene, in Escherichia coli Origami, a recombinant DvnV41 designated DvnRV41, which possesses four additional amino acids (AMDP) in the N-terminal region that result from enzymatic cleavage and retains the initial DvnV41 activity. To unravel the relationship between the structure of DvnRV41 and its particularly elevated activity, we produced by site-directed mutagenesis eight variants in which a single amino acid replacement was specifically introduced into the sequence. The point mutations were designed to change either conserved residues in class IIa bacteriocins or residues specific to DvnV41 located mainly in the C-terminal region. The fusion proteins were purified from the cytosoluble fractions by immobilized affinity chromatography. DvnRV41 and its variants were released from the fusion proteins by enzymatic cleavage, using enterokinase. The purity of DvnRV41 and of the variants was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, high-performance liquid chromatography, and mass spectrometry. The antibacterial activity of DvnRV41 and its variants was assessed using different indicator strains, including Listeria monocytogenes EGDe and Enterococcus faecalis JH2-2. The activity of all of the variants appeared to be less than the activity of DvnRV41. The decrease in activity did not appear to be related to a global conformational change, as determined by circular dichroism. Overall, the variants of DvnRV41 produced in the present study provide interesting insights into structure-activity relationships of class IIa bacteriocins.
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Carnobacterium: positive and negative effects in the environment and in foods.
FEMS microbiology reviews, 2007Co-Authors: Jorgen J Leisner, Hervé Prévost, Djamel Drider, Birgit Groth Laursen, Paw DalgaardAbstract:The genus Carnobacterium contains nine species, but only C. divergens and C. maltaromaticum are frequently isolated from natural environments and foods. They are tolerant to freezing/thawing and high pressure and able to grow at low temperatures, anaerobically and with increased CO2 concentrations. They metabolize arginine and various carbohydrates, including chitin, and this may improve their survival in the environment. Carnobacterium divergens and C. maltaromaticum have been extensively studied as protective cultures in order to inhibit growth of Listeria monocytogenes in fish and meat products. Several carnobacterial bacteriocins are known, and parameters that affect their production have been described. Currently, however, no isolates are commercially applied as protective cultures. Carnobacteria can spoil chilled foods, but spoilage activity shows intraspecies and interspecies variation. The responsible spoilage metabolites are not well characterized, but branched alcohols and aldehydes play a partial role. Their production of tyramine in foods is critical for susceptible individuals, but carnobacteria are not otherwise human pathogens. Carnobacterium maltaromaticum can be a fish pathogen, although carnobacteria are also suggested as probiotic cultures for use in aquaculture. Representative genome sequences are not yet available, but would be valuable to answer questions associated with fundamental and applied aspects of this important genus.
Xavier Dousset - One of the best experts on this subject based on the ideXlab platform.
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sensory characteristics of spoilage and volatile compounds associated with bacteria isolated from cooked and peeled tropical shrimps using spme gc ms analysis
International Journal of Food Microbiology, 2011Co-Authors: Emmanuel Jaffres, Josiane Cornet, Mireille Cardinal, Xavier Dousset, Valerie Lalanne, Sabrina Mace, Thierry Sérot, Jean-jacques JoffraudAbstract:Abstract The spoilage potential of six bacterial species isolated from cooked and peeled tropical shrimps ( Brochothrix thermosphacta , Serratia liquefaciens -like, Carnobacterium maltaromaticum , Carnobacterium divergens , Carnobacterium alterfunditum -like and Vagococcus penaei sp. nov.) was evaluated. The bacteria were inoculated into shrimps, packaged in a modified atmosphere and stored for 27 days at 8 °C. Twice a week, microbial growth, as well as chemical and sensory changes, were monitored during the storage period. The bacteria mainly involved in shrimp spoilage were B. thermosphacta , S. liquefaciens -like and C. maltaromaticum whose main characteristic odours were cheese-sour, cabbage-amine and cheese-sour-butter, respectively. The volatile fraction of the inoculated shrimp samples was analysed by solid-phase microextraction (SPME) and gas chromatography coupled to mass spectrometry (GC–MS). This method showed that the characteristic odours were most likely induced by the production of volatile compounds such as 3-methyl-1-butanal, 2,3-butanedione, 2-methyl-1-butanal, 2,3-heptanedione and trimethylamine.
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differentiation of closely related Carnobacterium food isolates based on 16s 23s ribosomal dna intergenic spacer region polymorphism
Applied and Environmental Microbiology, 2002Co-Authors: P Kabadjova, Xavier Dousset, Hervé PrévostAbstract:A novel strategy for identification of Carnobacterium food isolates based on restriction fragment length polymorphism (RFLP) of PCR-amplified 16S-23S ribosomal intergenic spacer regions (ISRs) was developed. PCR amplification from all Carnobacterium strains studied always yielded three ISR amplicons, which were designated the small ISR (S-ISR), the medium ISR (M-ISR), and the large ISR (L-ISR). The lengths of these ISRs varied from one species to another. Carnobacterium divergens NCDO 2763T and C. mobile DSM 4849T generated one major S-ISR band (ca. 400 bp) and minor M-ISR and L-ISR bands (ca. 500 and ca. 600 bp, respectively). The ISRs amplified from C. gallinarum NCFB 2766T and C. piscicola NCDO 2762T were larger (S-ISR, ca. 600 bp; M-ISR, ca. 700 bp; and L-ISR, ca. 800 bp). The L-ISR contained two tDNAs coding for tRNAIle and tRNAAla genes. The M-ISR included one tRNAAla gene, and the S-ISR did not contain a tDNA gene. The RFLP scheme devised involves estimation of variable PCR product sizes together with HinfI, TaqI, and HindIII restriction analysis. Forty-two isolates yielded four unique band patterns that correctly resolved these isolates into four Carnobacterium species. This method is very suitable for rapid, low-cost identification of a wide variety of Carnobacterium species without sequencing.
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growth of Carnobacterium divergens v41 and production of biogenic amines and divercin v41 in sterile cold smoked salmon extract at varying temperatures nacl levels and glucose concentrations
Journal of Food Protection, 2002Co-Authors: Nathalie Connil, M. F. Pilet, Hervé Prévost, Xavier Dousset, B. Onno, Leon Plissoneau, Mariefrance PiletAbstract:A complete factorial design 2 3 was used to study some aspects of Carnobacterium divergens V41 metabolism (growth, biogenic amine production, and divercin V41 production) in sterile cold-smoked salmon extract (SSE) at varying temperatures (3 to 9°C), NaCI levels (2.5 to 6.5%), and glucose concentrations (2 to 6 g liter 1 ). The results showed that temperature and NaCI content were the most influential factors on growth parameters in SSE. Predictive models are suggested for the assessment of C. divergens lag time (t lag ) and maximum specific growth rate (μ max ). Among the biogenic amines studied, only tyramine was found to be produced by C. divergens in SSE. Furthermore, we showed that temperature, NaCI, and glucose variations did not greatly affect tyramine and divercin V41 production by the bacteria under the experimental conditions used. Indeed, divercin V41, a bacteriocin from C. divergens V41 that is highly active against some Listeria strains, was produced in SSE even under harsh culture conditions. Similarly, tyramine production in SSE was delayed at 3°C but reached 35 μg ml -1 in all experiments after 27 days of storage. However, this final tyramine concentration in SSE is low compared with the threshold values of 100 to 800 μg g -1 reported as the potentially toxic dose in foods. Thus, we have found that C. divergens V41 is a promising strain for the biopreservation of refrigerated cold-smoked salmon. Carnobacterium divergens V41 est un agent bioprotecteur potentiel car il produit de la divercine 41 qui est une bacteriocine efficace contre L. monocytogenes. Le sujet de cette etude est de determiner le comportement de C. divergens V41 dans un extrait sterile de saumon fume a froid en simulant les conditions de stockage refrigerees et les concentrations sel/sucre du poisson. La multiplication de C. divergens V41 et la production de divercine 41 et d'amines biogenes sont etudiees en relation avec la variation de 3 facteurs technologiques : la temperature (de 3 a 9°C), la teneur en NaCl (de 2,5 a 6,5%) et la concentration en glucose (de 2 a 6g/l).
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Production of biogenic amines and divercin V41 in cold smoked salmon inoculated with Carnobacterium divergens V41, and specific detection of this strain by multiplex-PCR
Journal of applied microbiology, 2002Co-Authors: Nathalie Connil, Hervé Prévost, Xavier DoussetAbstract:N. C O N N I L , H. P R EV O S T A N D X. D O U S S E T. 2002. Aims: The objective of this study was to determine the technological behaviour (implantation and biogenic amines production) of Carnobacterium divergens V41, an anti-Listeria bacteriocin producer (divercin V41), after inoculation in cold smoked salmon (CSS). Methods and Results: Implantation of the strain was followed by multiplex-PCR during 27 days of storage at 4∞C, and biogenic amines were quantified by HPLC. It was found that the strain was able to develop quite well in CSS among lactic wild flora. Divercin V41 (400 AU ml )1 ) was produced in CSS, and the biogenic amine content was not modified by inoculation of the bacteria. Conclusions: Carnobacterium divergens V41 is a safe, interesting, bioprotective agent. Significance and Impact of the Study: This strain could potentially be used for efficient prevention of L. monocytogenes growth in CSS.
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Triton X-114 phase partitioning for the isolation of a pediocin-like bacteriocin from Carnobacterium divergens
Letters in applied microbiology, 2000Co-Authors: A. M. étivier, P Boyaval, Frédérique Duffes, Xavier Dousset, Jean-pierre Compoint, Didier MarionAbstract:A new procedure combining Triton X-114 phase partitioning and cation exchange chromatography was developed to purify a bacteriocin from a complex culture medium. This pediocin-like bacteriocin, secreted by Carnobacterium divergens and named divercin V41, was entirely recovered in the lower detergent-rich phase whereas all other substances (compounds from culture medium, bacterial metabolites) remained in the upper detergent-poor phase. Subsequent cation-exchange chromatography of the TX-114-rich phase allowed recovery of the pure active bacteriocin and also detergent removing. This new purification method is versatile, fast (only two steps) and can be carried out on whole broth.
M. F. Pilet - One of the best experts on this subject based on the ideXlab platform.
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Draft Genome Sequence of Carnobacterium divergens V41, a Bacteriocin-Producing Strain
Genome Announcements, 2016Co-Authors: Benoit Remenant, M. F. Pilet, Anne Marie Revol-junelles, Hervé Prévost, Laurent Marché, Frederic Borges, Catherine Cailliez-grimal, Aurélie Lajus, Claudine Médigue, Monique ZagorecAbstract:In this study, we present the draft genome sequence of Carnobacterium divergens V41. This strain was previously reported as producing divercin V41, a bacteriocin of interest for food biopreservation. Its genome revealed also the presence of a gene cluster putatively involved in polyketide production, which is unique in lactic acid bacteria.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, twelve factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulphate, manganese sulphate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5-8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2-20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 x 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g-1) during five weeks of vacuum storage at 4° and 8°C.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, 12 factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulfate, manganese sulfate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5–8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2–20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 × 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g−1) during 5 weeks of vacuum storage at 4 and 8°C.
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effect of inoculation of Carnobacterium divergens v41 a biopreservative strain against listeria monocytogenes risk on the microbiological chemical and sensory quality of cold smoked salmon
International Journal of Food Microbiology, 2005Co-Authors: Anne Brillet, M. F. Pilet, Hervé Prévost, Mireille Cardinal, Francoise LeroiAbstract:The aim of this study was to develop a biopreservation strategy for cold-smoked salmon (CSS) by the use of lactic acid bacteria previously selected for their capability to inhibit the growth of Listeria monocytogenes in the product. The spoiling potential of three Carnobacterium strains (Carnobacterium divergens V41, Carnobacterium piscicola V1 and SF668) was tested in sterile CSS blocks inoculated by 104-5 CFU g− 1 and stored under vacuum for 9 days at 4 °C followed by 19 days at 8 °C. C. divergens V41 grew a little faster than the other strains and none of the three carnobacteria showed any adverse effect on quality of the product, i.e. no off-odour detected by a trained panel, no total volatile basic nitrogen (TVBN) production, no acidification and no biogenic amine except a slight production of tyramine. An application on commercial CSS was tested by spraying C. divergens V41 (104-5 CFU g− 1) on slices of four batches freshly processed in different smokehouses. Microbial, chemical and sensory characteristics were weekly compared to a control during 4 weeks of vacuum storage. When the natural microflora was initially weak (two batches 104-5 CFU g− 1), no effect on the microflora, TVBN and biogenic amine production, nor on the sensory characteristics was observed in presence of C. divergens V41. In conclusion, biopreservation of CSS using lactic acid bacteria such as C. divergens V41 is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the quality of the product.
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biodiversity of listeria monocytogenes sensitivity to bacteriocin producing Carnobacterium strains and application in sterile cold smoked salmon
Journal of Applied Microbiology, 2004Co-Authors: Anne Brillet, M. F. Pilet, A Bouttefroy, Hervé Prévost, Francoise LeroiAbstract:Aims: The aim of this study was to demonstrate the inhibitory capacity of Carnobacterium strains against a collection of Listeria monocytogenes strains in cold-smoked salmon (CSS). Methods and Results: Three bacteriocin-producing strains, Carnobacterium divergens V41, C. piscicola V1 and C. piscicola SF668, were screened for their antilisterial activity against a collection of 57 L. monocytogenes strains selected from the French smoked salmon industry, using an agar spot test. All the Listeria strains were inhibited but three different groups could be distinguished differing in sensitivity to the three Carnobacterium strains. However, C. divergens V41 always had the highest inhibitory effect. The antilisterial capacity was then tested in sterile CSS blocks co-inoculated with Carnobacterium spp. and mixtures of L. monocytogenes strains. C. divergens V41 was the most efficient strain, maintaining the level of L. monocytogenes at <50 CFU g−1 during the 4 weeks of vacuum storage at 4 and 8°C, whatever the sensitivity of the set of L. monocytogenes strains. Conclusions: C. divergens V41 may be a good candidate for biopreservation in CSS. Significance and Impact of the Study: A biopreservation strategy for CSS against the risk of L. monocytogenes was investigated using bacteriocin-producing lactic acid bacteria.
L. Axelsson - One of the best experts on this subject based on the ideXlab platform.
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Probiotic Carnobacterium divergens increase growth parameters and disease resistance in farmed Atlantic cod (Gadus morhua) larvae without influencing the microbiota
Aquaculture, 2021Co-Authors: V. Puvanendran, I. Rud, Breiland Msw, J.a. Arnesen, L. AxelssonAbstract:Abstract Aquaculture represents the fastest growing food sector and the second largest export commodity in Norway. Disease in aquaculture causes mortality and huge losses in farmed fish. Probiotic treatment of farmed fish, i.e. feeding of fish with live, beneficial microorganisms, may represent one part of a sustainable solution to these problems. Some carnobacteria of fish origin have shown promising results as probiotics for fish. In this study, two Carnobacterium divergens strains were fed to Atlantic cod (Gadus morhua) larvae through intermittent feeding with Artemia franciscana containing the bacterial strains. Cod larvae fed with the carnobacteria showed a significantly higher growth and survival during the larval rearing stage compared to the larvae fed A. franciscana with no carnobacteria (control treatment). Following the probiotic feeding period, the cod larvae were challenged with a pathogenic bacterium, Vibrio anguillarum. Cod larvae from probiotic treatment showed significantly better disease resistance compared to the control. Microbiota analysis by 16S rRNA amplicon sequencing verified that enrichment of carnobacteria in the A. franciscana feed. Analysis of the whole larvae detected only minor relative levels of carnobacteria in the probiotic treated larvae, which was non-significant compared to the control larvae (p = 0.062). The probiotic treatment had no significant impact on the overall microbiota diversity or composition in the larvae during the probiotic feeding period or after the disease challenge. Despite this, significantly improved growth and survival during larval rearing and post-pathogen challenge suggest probiotic effects of C. divergens mixture on cod larval fish performance and welfare. Studies examining the mode of action should be carried out to get more insight to lead to the commercial application of C. divergens in Atlantic cod larviculture.
Francoise Leroi - One of the best experts on this subject based on the ideXlab platform.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, twelve factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulphate, manganese sulphate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5-8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2-20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 x 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g-1) during five weeks of vacuum storage at 4° and 8°C.
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Optimization of Growth and Bacteriocin Activity of the Food Bioprotective Carnobacterium divergens V41 in an Animal Origin Protein Free Medium
Frontiers in Marine Science, 2016Co-Authors: M. F. Pilet, Francoise Leroi, Hervé Prévost, Anne Brillet-viel, Philippe Courcoux, Mariefrance PiletAbstract:Optimization of Carnobacterium divergens V41 growth and bacteriocin activity in a culture medium deprived of animal protein, needs for food bioprotection, was performed by using a statistical approach. In a screening experiment, 12 factors (pH, temperature, carbohydrates, NaCl, yeast extract, soy peptone, sodium acetate, ammonium citrate, magnesium sulfate, manganese sulfate, ascorbic acid and thiamine) were tested for their influence on the maximal growth and bacteriocin activity using a two-level incomplete factorial design with 192 experiments performed in microtiter plate wells. Based on results, a basic medium was developed and three variables (pH, temperature and carbohydrates concentration) were selected for a scale-up study in bioreactor. A 23 complete factorial design was performed, allowing the estimation of linear effects of factors and all the first order interactions. The best conditions for the cell production were obtained with a temperature of 15°C and a carbohydrates concentration of 20 g/l whatever the pH (in the range 6.5–8), and the best conditions for bacteriocin activity were obtained at 15°C and pH 6.5 whatever the carbohydrates concentration (in the range 2–20 g/l). The predicted final count of C. divergens V41 and the bacteriocin activity under the optimized conditions (15°C, pH 6.5, 20 g/l carbohydrates) were 2.4 × 1010 CFU/ml and 819200 AU/ml respectively. C. divergens V41 cells cultivated in the optimized conditions were able to grow in cold-smoked salmon and totally inhibited the growth of Listeria monocytogenes (< 50 CFU g−1) during 5 weeks of vacuum storage at 4 and 8°C.
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effect of inoculation of Carnobacterium divergens v41 a biopreservative strain against listeria monocytogenes risk on the microbiological chemical and sensory quality of cold smoked salmon
International Journal of Food Microbiology, 2005Co-Authors: Anne Brillet, M. F. Pilet, Hervé Prévost, Mireille Cardinal, Francoise LeroiAbstract:The aim of this study was to develop a biopreservation strategy for cold-smoked salmon (CSS) by the use of lactic acid bacteria previously selected for their capability to inhibit the growth of Listeria monocytogenes in the product. The spoiling potential of three Carnobacterium strains (Carnobacterium divergens V41, Carnobacterium piscicola V1 and SF668) was tested in sterile CSS blocks inoculated by 104-5 CFU g− 1 and stored under vacuum for 9 days at 4 °C followed by 19 days at 8 °C. C. divergens V41 grew a little faster than the other strains and none of the three carnobacteria showed any adverse effect on quality of the product, i.e. no off-odour detected by a trained panel, no total volatile basic nitrogen (TVBN) production, no acidification and no biogenic amine except a slight production of tyramine. An application on commercial CSS was tested by spraying C. divergens V41 (104-5 CFU g− 1) on slices of four batches freshly processed in different smokehouses. Microbial, chemical and sensory characteristics were weekly compared to a control during 4 weeks of vacuum storage. When the natural microflora was initially weak (two batches 104-5 CFU g− 1), no effect on the microflora, TVBN and biogenic amine production, nor on the sensory characteristics was observed in presence of C. divergens V41. In conclusion, biopreservation of CSS using lactic acid bacteria such as C. divergens V41 is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the quality of the product.
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biodiversity of listeria monocytogenes sensitivity to bacteriocin producing Carnobacterium strains and application in sterile cold smoked salmon
Journal of Applied Microbiology, 2004Co-Authors: Anne Brillet, M. F. Pilet, A Bouttefroy, Hervé Prévost, Francoise LeroiAbstract:Aims: The aim of this study was to demonstrate the inhibitory capacity of Carnobacterium strains against a collection of Listeria monocytogenes strains in cold-smoked salmon (CSS). Methods and Results: Three bacteriocin-producing strains, Carnobacterium divergens V41, C. piscicola V1 and C. piscicola SF668, were screened for their antilisterial activity against a collection of 57 L. monocytogenes strains selected from the French smoked salmon industry, using an agar spot test. All the Listeria strains were inhibited but three different groups could be distinguished differing in sensitivity to the three Carnobacterium strains. However, C. divergens V41 always had the highest inhibitory effect. The antilisterial capacity was then tested in sterile CSS blocks co-inoculated with Carnobacterium spp. and mixtures of L. monocytogenes strains. C. divergens V41 was the most efficient strain, maintaining the level of L. monocytogenes at <50 CFU g−1 during the 4 weeks of vacuum storage at 4 and 8°C, whatever the sensitivity of the set of L. monocytogenes strains. Conclusions: C. divergens V41 may be a good candidate for biopreservation in CSS. Significance and Impact of the Study: A biopreservation strategy for CSS against the risk of L. monocytogenes was investigated using bacteriocin-producing lactic acid bacteria.
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inhibition of listeria monocytogenes by in situ produced and semipurified bacteriocins of Carnobacterium spp on vacuum packed refrigerated cold smoked salmon
Journal of Food Protection, 1999Co-Authors: Frédérique Duffes, Francoise Leroi, Xavier Dousset, C Corre, P BoyavalAbstract:Listeria monocytogenes inhibition by Carnobacterium strains and crude bacteriocins on sterile and commercial vacuum-packed cold-smoked salmon stored at 4°C and 8°C was investigated. Carnobacterium piscicola V1 was bactericidal against L. monocytogenes at the two temperatures, whereas Carnobacterium divergens V41 presented a bacteriostatic effect. C. piscicola SF668 delayed L. monocytogenes growth at 8°C and had a bacteriostatic effect at 4°C. Listeria growth was not affected by a non-bacteriocin-producing C. piscicola. Crude extracts of piscicocins were bactericidal at 4°C and 8°C. Listeria growth was delayed by divercin V41 at 8°C and was inhibited at 4°C. Nisin delayed Listeria growth at 8°C and was bacteriostatic at 4°C. The present study demonstrates that L. monocytogenes growth could be prevented on vacuum-packed cold-smoked salmon by Carnobacterium and associated bacteriocins at chilled temperatures. Moreover, no product spoilage could be observed with the use of such bacteriocin-producing strains as demonstrated by good sensorial analyses and low biogenic amine production.