References of "Crevecoeur, Sébastien"
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See detailIn vitro screening of mare's milk antimicrobial effect and antiproliverative activity.
Guri, Anilda; Paligot, Michèle; Crevecoeur, Sébastien ULg et al

in FEMS Microbiology Letters (2016)

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See detailOptmization of culture media for Bifidobacterium bifidum and Bifidobacterium crudilactis and study of the antimicrobial effect of culture supernatants
Bondue, Pauline ULg; Delcenserie, Véronique ULg; Crevecoeur, Sébastien ULg et al

Poster (2015, October)

Complex oligosaccharides from human milk (HMO) contribute to infant health. Bifidobacteriumbifidum mainly found in breast-fed infant microbiota has all the enzymatic machinery for degradation of HMO. On ... [more ▼]

Complex oligosaccharides from human milk (HMO) contribute to infant health. Bifidobacteriumbifidum mainly found in breast-fed infant microbiota has all the enzymatic machinery for degradation of HMO. On the other hand, whey is rich in complex bovin milk oligosaccharides (BMO) very similar to HMO, including 3’-sialyllactose (3’SL). They are very likely to be metabolised by B. bifidum too, but also by B. crudilactis, a bovine origin strain. Fermentation of HMO or BMO by bifidobacteria can result in production of metabolites modulating virulence expression of several pathogenic bacteria. Two strains of bifidobacteria were used in this study: B. bifidum, isolated from breastfed infant feces and B. crudilactis, isolated from bovine raw milk. The ability of those strains to metabolise culture media enriched in glucose, whey and 3’SL has been assessed. Then, the obtained culture supernatant has been tested against virulence genes expression of E. coli O157:H7.  Both strains were able to grow in presence of BMO and 3’SL. B. crudilactis presented the best growth on all media. All culture supernatants obtained after supplementation with 3’SL resulted in significant under-expression of genes ler and qseA. The trend of genes stxB2 and luxS was also toward a down-regulation. BMO combined to some bovine or human origin bifidobacteria strains could be interesting synbiotics to maintain or restore the intestinal health of young children. These effects observed in vitro require further investigations to ensure repeatability in humans and to identify the exact nature of molecules obtained from fermentation media by B. bifidum and B. crudilactis. [less ▲]

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See detailOptimisation de milieux de culture pour Bifidobacterium bifidum et Bifidobacterium crudilactis et étude de l’effet antimicrobien des surnageants de culture
Bondue, Pauline ULg; Delcenserie, Véronique ULg; Crevecoeur, Sébastien ULg et al

Poster (2015, June)

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est ... [more ▼]

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est notamment dû à la présence d’oligosaccharides complexes dans le lait maternel (HMO). Les oligosaccharides ajoutés au lait maternisé sont d’origine végétale et leur structure est très éloignée de celle des HMO. Parce que les HMO ressemblent aux glycans de la paroi épithéliale, les pathogènes intestinaux infantiles s’y fixent et sont expulsés naturellement. Le lait de vache possède des oligosaccharides complexes (BMO), dont la structure est très similaire à celle des HMO. Les bifidobactéries rencontrées majoritairement dans les matières fécales d’un nourrisson devraient pouvoir métaboliser les BMO, tout comme celles isolées dans le lait de vache. Les objectifs de cette étude étaient d’étudier le potentiel de croissance de bifidobactéries d’origine bovine ou humaine sur des milieux de culture enrichis en lactosérum et BMO. Le deuxième objectif était de vérifier si le catabolisme de ces sucres complexes induisaient une synthèse de métabolites influençant l’expression de virulence de certains pathogènes tels qu’Escherichia coli O157 :H7. Une souche de Bifidobacterium bifidum, isolée à partir des matières fécales d’un nourrisson exclusivement allaité et une souche de Bifidobacterium crudilactis, isolée à partir de fromage au lait cru, ont été mises en culture dans des milieux contenant différentes sources d’hydrates de carbone (glucose, lactosérum naturellement riche en lactose et BMO, et 3’-syalillactose (3’SL)). Le 3’SL est un oligosaccharide complexe majoritaire parmi les BMO. Les surnageants des différents milieux de culture ont été prélevés et concentrés par lyophilisation puis mis en contact avec E. coli O157 :H7. L’expression relative de différents gènes de virulence d’E. coli O157:H7, fliC, ler, stx2b et luxS a été étudiée. Dans le futur, les BMO et certaines souches d’origine bovine ou humaine pourraient s’avérer être des compléments alimentaires intéressants pour maintenir ou rétablir la santé intestinale des jeunes enfants. [less ▲]

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See detailShort communication: Evaluation of the microbiota of kefir samples using metagenetic analysis targeting the 16S and 26S ribosomal DNA fragments
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Leclercq, Mathilde et al

in Journal of Dairy Science (2015), 98

Milk kefir is produced by fermenting milk in the presence of kefir grains. This beverage has several benefits for human health. The aim of this experiment was to analyze 5 kefir grains (and their products ... [more ▼]

Milk kefir is produced by fermenting milk in the presence of kefir grains. This beverage has several benefits for human health. The aim of this experiment was to analyze 5 kefir grains (and their products) using a targeted metagenetic approach. Of the 5 kefir grains analyzed, 1 was purchased in a supermarket, 2 were provided by the Ministry of Agriculture (Namur, Belgium), and 2 were provided by individuals. The metagenetic approach targeted the V1-V3 fragment of the 16S ribosomal (r)DNA for the grains and the resulting beverages at 2 levels of grain incorporation (5 and 10%) to identify the bacterial species population. In contrast, the 26S rDNA pyrosequencing was performed only on kefir grains with the aim of assessing the yeast populations. In parallel, pH measurements were performed on the kefir obtained from the kefir grains using 2 incorporation rates. Regarding the bacterial population, 16S pyrosequencing revealed the presence of 20 main bacterial species, with a dominance of the following: Lactobacillus kefiranofaciens, Lactococcus lactis ssp. cremoris, Gluconobacter frateurii, Lactobacillus kefiri, Acetobacter orientalis, and Acetobacter lovaniensis. An important difference was noticed between the kefir samples: kefir grain purchased from a supermarket (sample E) harbored a much higher proportion of several operational taxonomic units of Lactococcus lactis and Leuconostoc mesenteroides. This sample of grain was macroscopically different from the others in terms of size, apparent cohesion of the grains, structure, and texture, probably associated with a lower level of Lactobacillus kefiranofaciens. The kefir (at an incorporation rate of 5%) produced from this sample of grain was characterized by a lower pH value (4.5) than the others. The other 4 samples of kefir (5%) had pH values above 5. Comparing the kefir grain and the kefir, an increase in the population of Gluconobacter in grain sample B was observed. This was also the case for Acetobacter orientalis in sample D. In relation to 26S pyrosequencing, our study revealed the presence of 3 main yeast species: Naumovozymaspp., Kluyveromyces marxianus, and Kazachastania khefir. For Naumovozyma, further studies are needed to assess the isolation of new species. In conclusion, this study has proved that it is possible to establish the patterns of bacterial and yeast composition of kefir and kefir grain. This was only achieved with the use of high-throughput sequencing techniques. [less ▲]

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See detailMicrobiota characterization of a protected designation of origin Belgian cheese: Herve cheese, using metagenomic analysis.
Delcenserie, Véronique ULg; Taminiau, Bernard ULg; Delhalle, Laurent ULg et al

in Journal of Dairy Science (2014), 97

Herve cheese is a Belgian soft cheese with a washed rind, and is made from raw or pasteurized milk. The specific microbiota of this cheese has never previously been fully explored and the use of raw or ... [more ▼]

Herve cheese is a Belgian soft cheese with a washed rind, and is made from raw or pasteurized milk. The specific microbiota of this cheese has never previously been fully explored and the use of raw or pasteurized milk in addition to starters is assumed to affect the microbiota of the rind and the heart. The aim of the study was to analyze the bacterial microbiota of Herve cheese using classical microbiology and a metagenomic approach based on 16S ribosomal DNA pyrosequencing. Using classical microbiology, the total counts of bacteria were comparable for the 11 samples of tested raw and pasteurized milk cheeses, reaching almost 8 log cfu/g. Using the metagenomic approach, 207 different phylotypes were identified. The rind of both the raw and pasteurized milk cheeses was found to be highly diversified. However, 96.3 and 97.9% of the total microbiota of the raw milk and pasteurized cheese rind, respectively, were composed of species present in both types of cheese, such as Corynebacterium casei, Psychrobacter spp., Lactococcus lactis ssp. cremoris, Staphylococcus equorum, Vagococcus salmoninarum, and other species present at levels below 5%. Brevibacterium linens were present at low levels (0.5 and 1.6%, respectively) on the rind of both the raw and the pasteurized milk cheeses, even though this bacterium had been inoculated during the manufacturing process. Interestingly, Psychroflexus casei, also described as giving a red smear to Raclettetype cheese, was identified in small proportions in the composition of the rind of both the raw and pasteurized milk cheeses (0.17 and 0.5%, respectively). In the heart of the cheeses, the common species of bacteria reached more than 99%. The main species identified were Lactococcus lactis ssp. cremoris, Psychrobacter spp., and Staphylococcus equorum ssp. equorum. Interestingly, 93 phylotypes were present only in the raw milk cheeses and 29 only in the pasteurized milk cheeses, showing the high diversity of the microbiota. Corynebacterium casei and Enterococcus faecalis were more prevalent in the raw milk cheeses, whereas Psychrobacter celer was present in the pasteurized milk cheeses. However, this specific microbiota represented a low proportion of the cheese microbiota. This study demonstrated that Herve cheese microbiota is rich and that pasteurized milk cheeses are microbiologically very close to raw milk cheeses, probably due to the similar manufacturing process. The characterization of the microbiota of this particular protected designation of origin cheese was useful in enabling us to gain a better knowledge of the bacteria responsible for the character of this cheese. [less ▲]

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See detailLes modèles de microbiologie prévisionellepour la maitrise de la sécurité des aliments (synthèse bibliographique)
Delhalle, Laurent ULg; Daube, Georges ULg; Adolphe, Ysabelle ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(3), 369-381

Predictive microbiology aims to predict the evolution of microorganisms in foods with mathematical models. Several models have been published and the complexity of some of them makes their use difficult ... [more ▼]

Predictive microbiology aims to predict the evolution of microorganisms in foods with mathematical models. Several models have been published and the complexity of some of them makes their use difficult for the uninitiated. However, the use of this discipline will become widespread in coming years. These models provide, for example, additional tools to ensure the microbiological safety of food, to establish the contamination flow in a food chain, to develop and to assist the quality assurance systems. The development of new computer software and database will enable stakeholders in the food chain to have a better control of microbiological hazards. The aim of this summary is to give an overview of existing models of predictive microbiology and their applications. A first approach of the primary, secondary and tertiary models is given. The modelling of latency, integrated models and growth tests are also discussed. [less ▲]

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See detailA new tool to control meat products safety: a web based application of predictive microbiology models
Delhalle, Laurent ULg; Adolphe, Ysabelle ULg; Crevecoeur, Sébastien ULg et al

Conference (2011)

Predictive microbiology is considered by the European legislation as a tool to control food safety. Meat and meat products are particularly sensitive to contamination with pathogens. However, development ... [more ▼]

Predictive microbiology is considered by the European legislation as a tool to control food safety. Meat and meat products are particularly sensitive to contamination with pathogens. However, development of predictive microbiology models and interpretation of results require specific knowledge. A free web based model has been developed for an easy use by people who are not experts in this field as industries and public authorities. The model can simulate the growth of Salmonella spp, Listeria monocytogenes and Escherichia coli O157 in minced pork meat and on pork meat product (white pudding) under different environmental conditions. The model provides simulations under static or dynamic conditions over time. The user also has the opportunity to import the specific growth rate and cardinal parameters of a bacterium. Unlike polynomial models currently available, this free web access model is distinguished by the use of secondary square roots and primary logistic model with delay. This model permits to have a real time process management, to prospect new formulation for safer products or to design safer processes, to estimate the shelf life of a food product, etc [less ▲]

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See detailModeling Microbial Cross-contamination in Quick Service Restaurants by Means of Experimental Simulations With Bacillus Spores
Baptista Rodrigues, Ana Lúcia ULg; Crevecoeur, Sébastien ULg; Dure, Remi et al

Poster (2010)

Cross contamination has been frequently mentioned as being in the origin of a wide range of food borne outbreaks. Handling of food is one of the ways through which cross contamination may occur. For many ... [more ▼]

Cross contamination has been frequently mentioned as being in the origin of a wide range of food borne outbreaks. Handling of food is one of the ways through which cross contamination may occur. For many different reasons, quick service restaurants are particularly at risk. Due to its importance, cross contamination via the hands should be taken into consideration when carrying out a quantitative risk assessment. The main goal of this study was to determine transfer rates of bacteria to and via the hands, reduction rates of two hand sanitizing procedures and to apply the results to a quantitative microbial risk assessment model. According to our results, handling of a portion of raw minced meat contaminated at 4.104 cfu leads to the presence of 24 cfu on both hands, 3 cfu on ready-to-eat product (RTE) manipulated with unwashed hands, 1 cfu on RTE manipulated with wiped hands and absence on RTE manipulated with washed hands. This study provides adequate quantitative data for quantitative microbial risk assessment. [less ▲]

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