References of "Delcenserie, Véronique"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailStudy of the microbial flora of steak tartare by metagenomic approach
Korsak Koulagenko, Nicolas ULg; Delhalle, Laurent ULg; Nezer, Carine et al

Poster (2014, May 06)

Detailed reference viewed: 29 (3 ULg)
Full Text
Peer Reviewed
See detailValidation of real-time PCR for detection of six major pathogens in seafood products
Taminiau, Bernard ULg; Korsak Koulagenko, Nicolas ULg; Lemaire et al

in Food Control (2014), 44

Seafood can pose a public health concern to consumers. It is often consumed rawand may be contaminated with several foodborne pathogens. In order to guarantee the safety of seafood, real-time polymerase ... [more ▼]

Seafood can pose a public health concern to consumers. It is often consumed rawand may be contaminated with several foodborne pathogens. In order to guarantee the safety of seafood, real-time polymerase chain reaction (PCR) protocols may be used as these enable results to be provided within 24 h. The first goal of our work was to develop real-time PCR protocols enabling the detection of six foodborne pathogens that may be present in seafood products (Campylobacter jejuni, Campylobacter coli, enterohemorrhagic Escherichia coli, Salmonella spp., Vibrio parahaemolyticus, and Vibrio vulnificus). The corresponding gene targets were: 50S/VS1, rfbE, ttr, tlh, and vvp. A multiplex PCR was also developed to detect the virulence genes of V. parahaemolyticus: tdh and trh. A total of 420 bacterial strains belonging to four different genera/strains were used in this study. Sensitivity and specificity were always 100%, except in the case of Salmonella spp., where three strains were not detected by our PCR protocols. The second objective of our work was to assess the detection limit of our real-time PCR protocols on artificially contaminated seafood products (raw shrimps, cooked shrimps, and raw mussels), purchased in public stores. Six different levels of contamination were assayed in four replicates for each matrix. The real-time PCR protocols enabled a better level of detection than the ISO methods, except for Salmonella in raw shrimps and for V. vulnificus in shrimps (raw and cooked). The estimated level of detection was between 1 and 47 cfu/25 g sample for the ISO norms and between 1 and 315 cfu/25 g sample for the realtime PCR protocols tailored in our work. The real-time PCRs developed in our work allowed for good selectivity, sensitivity, and specificity. The sensitivity on seafood products was estimated at a level of 100%, except for Salmonella (97%). In the spiking assays, the levels of detection were lower with the real-time PCR protocol than those obtained with the ISO method. This was not the case for V. vulnificus in raw and cooked shrimps and for Salmonella in raw shrimps. These real-time PCR protocols appear to be good alternative methods for surveillance of seafood products to ensure the absence of foodborne pathogens. One additional conclusion is that laboratories have to use enrichment media that are compatible with those recommended by ISO standards. This may facilitate the isolation of the pathogen if the real-time PCR protocol gives a suspect positive signal during the first step of the seafood analysis. [less ▲]

Detailed reference viewed: 38 (17 ULg)
Full Text
Peer Reviewed
See detailComparative genomics to investigate the evolutionary development of the genus Bifidobacterium
Lugli, Gabriele; Milani, Christian; Turroni, Francesca et al

in Applied and Environmental Microbiology (2014)

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailGenome encyclopaedia of type strains of the genus Bifidobacterium
Milani, Christian; Lugli, Gabriele; Duranti, Sabrina et al

in Applied and Environmental Microbiology (2014)

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 38 (21 ULg)
Full Text
Peer Reviewed
See detailProbiotics and health claims in Europe
Delcenserie, Véronique ULg

Conference (2013, November 05)

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailGlucose decreases virulence gene expression of Escherichia coli O157:H7
Delcenserie, Véronique ULg; LaPointe, Gisèle; Charaslertrangsi, Tumnoon et al

in Journal of Food Protection (2012)

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailBovine milk fat globule membrane affects virulence expression in Escherichia coli O157:H7
Tellez, Angela; Corredig, Milena; Guri, Anilda et al

in Journal of Dairy Science (2012)

Detailed reference viewed: 26 (4 ULg)
Full Text
Peer Reviewed
See detailBifidobacterium pseudolongum are efficient indicators of animal fecal contamination in raw milk cheese industry
Delcenserie, Véronique ULg; Gavini, Françoise; China, Bernard et al

in BMC Microbiology (2011), 11(178),

Background: The contamination of raw milk cheeses (St-Marcellin and Brie) from two plants in France was studied at several steps of production (raw milk, after addition of rennet - St-Marcellin - or after ... [more ▼]

Background: The contamination of raw milk cheeses (St-Marcellin and Brie) from two plants in France was studied at several steps of production (raw milk, after addition of rennet - St-Marcellin - or after second maturation - Brie -, after removal from the mold and during ripening) using bifidobacteria as indicators of fecal contamination. Results: Bifidobacterium semi-quantitative counts were compared using PCR-RFLP and real-time PCR. B. pseudolongum were detected in 77% (PCR-RFLP; 1.75 to 2.29 log cfu ml-1) at the different production steps) and 68% (real-time PCR; 2.19 to 2.73 log cfu ml-1) of St-Marcellin samples and in 87% (PCR-RFLP; 1.17 to 2.40 log cfu ml-1) of Brie cheeses samples. Mean counts of B. pseudolongum remained stable along both processes. Two other populations of bifidobacteria were detected during the ripening stage of St-Marcellin, respectively in 61% and 18% of the samples (PCR-RFLP). The presence of these populations explains the increase in total bifidobacteria observed during ripening. Further characterization of these populations is currently under process. Forty-eight percents (St-Marcellin) and 70 % (Brie) of the samples were B. pseudolongum positive / E. coli negative while only 10 % (St-Marcellin) and 3 % (Brie) were B. pseudolongum negative / E. coli positive. Conclusions: The increase of total bifidobacteria during ripening in Marcellin’s process does not allow their use as fecal indicator. The presence of B. pseudolongum along the processes defined a contamination from animal origin since this species is predominant in cow dung and has never been isolated in human feces. B. pseudolongum was more sensitive as an indicator than E. coli along the two different cheese processes. B. pseudolongum should be used as fecal indicator rather than E. coli to assess the quality of raw milk and raw milk cheeses. Results: Bifidobacterium semi-quantitative counts were compared using PCR-RFLP and real-time PCR. Bif. pseudolongum were detected in 77% (PCR-RFLP; 1.75 to 2.29 log cfu ml-1) at the different production steps) and 68% (real-time PCR; 2.19 to 2.73 log cfu ml-1) of St-Marcellin samples and in 87% (PCR-RFLP; 1.17 to 2. 40 log cfu ml-1) of Brie cheeses samples. Mean counts of Bif. pseudolongum remained stable along both processes. Two other populations of bifidobacteria were detected during the ripening stage of St-Marcellin, respectively in 61% and 18% of the samples (PCR-RFLP). The presence of these populations explains the increase in total bifidobacteria observed during ripening. Further identification of these species is currently under process. Forty-eight percents (St-Marcellin) and 70 % (Brie) of the samples were Bif. pseudolongum positive / E. coli negative while only 10 % (St-Marcellin) and 3 % (Brie) were Bif. pseudolongum negative / E. coli positive. Conclusions: The increase of total bifidobacteria during ripening in Marcellin’s process does not allow their use as fecal indicator. The presence of Bif. pseudolongum along the processes defined a contamination from animal origin since this species is predominant in cow dung and has never been isolated in human feces. Bif. pseudolongum was more sensitive as an indicator than E. coli along the two different cheese processes. Bif. pseudolongum should be used as fecal indicator rather than E. coli to assess the quality of raw milk and raw milk cheeses. [less ▲]

Detailed reference viewed: 52 (18 ULg)
Full Text
Peer Reviewed
See detailGenome comparison of Bifidobacterium longum strains NCC2705 and CRC-002 using suppression subtractive hybridization.
Delcenserie, Véronique ULg; Lessard, Marie*-Helene; LaPointe, Gisele et al

in FEMS Microbiology Letters (2008), 280(1), 50-6

Because probiotic effects are strain dependent, genomic explanations of these differences will contribute to understanding their mechanisms of action. The genomic sequence of the Bifidobacterium longum ... [more ▼]

Because probiotic effects are strain dependent, genomic explanations of these differences will contribute to understanding their mechanisms of action. The genomic sequence of the Bifidobacterium longum probiotic strain NCC2705 was determined, but little is known about the genetic diversity between strains of this species. Suppression subtractive hybridization (SSH) is a powerful method for generating a set of DNA fragments differing between two closely related bacterial strains. The purpose of this study was to identify genetic differences between genomes of B. longum strains NCC2705 and CRC-002 using PCR-based SSH. Strain CRC-002 produces exopolysaccharides whereas NCC2705 is not known for reliable exopolysaccharide production. Thirty-five and 30 different sequences were obtained from the SSH libraries of strains CRC-002 and NCC2705, respectively. Specific CRC-002 genes found were predicted to be involved in the biosynthesis of exopolysaccharides and metabolism of other carbohydrates, and these genes were not present in the genome of strain NCC2705. The identification of an endo-1,4-beta-xylanase gene in the CRC-002 SSH library is an important difference because xylanase genes have previously been proposed as a defining characteristic of the NCC2705 strain. The results demonstrate that the SSH technique was useful to highlight potential genes involved in complex sugar metabolism that differ between the two probiotic strains. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailImmunomodulatory effects of probiotics in the intestinal tract.
Delcenserie, Véronique ULg; Martel, D.; Lamoureux, M. et al

in Current Issues in Molecular Biology (2008), 10(1-2), 37-54

The intestinal microbiota is the largest source of microbial stimulation that exerts both harmful and beneficial effects on human health. The interaction between probiotic and enterocytes is the ... [more ▼]

The intestinal microbiota is the largest source of microbial stimulation that exerts both harmful and beneficial effects on human health. The interaction between probiotic and enterocytes is the initiating event in immunomodulation and merits particular attention. The effects of probiotic is strain dependent and for each new probiotic strain, profiles of cytokines secreted by lymphocytes, enterocytes or dendritic cells that come in contact with the strain should be systematically established. To evaluate the effects of probiotics on the immune system, models that mimic the mucosa, and thus the physiological reality, should be preferred whenever it is possible. Then, the in vitro observed effects should be backed up by properly conducted randomized double bind clinical studies. More detailed studies are needed to determine the precise action mode of probiotics on both mucosal and systemic immunity. [less ▲]

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailBifidobacteria as indicators of faecal contamination along a sheep meat production chain
Delcenserie, Véronique ULg; Loncaric, D.; Bonaparte, Christine et al

in Journal of Applied Microbiology (2008), 104(1), 276-284

Aims: The potential use of bifidobacteria as indicators for faecal contamination was studied along a sheep meat production and processing chain. The levels of bifidobacteria were compared with those of ... [more ▼]

Aims: The potential use of bifidobacteria as indicators for faecal contamination was studied along a sheep meat production and processing chain. The levels of bifidobacteria were compared with those of Escherichia coli. Total viable counts were followed along the chain (244 samples). Methods and Results: Forty-three per cent of the samples contained bifidobacteria, of which 15% were solely detected using a PCR method based on the hsp60 gene and not by a culture-based method. Bifidobacteria were detected in only three of nine sheep faeces samples using one or the other method. However, carcasses (types C and E) were highly contaminated. These sample types (30% and 28%, respectively) were positive for bifidobacteria and negative for E. coli. The species Bifidobacterium pseudolongum and Bif. thermophilum, isolated from faecal samples, were predominant. Bifidobacterium choerinum were found in C, D, E and F sample types. Conclusions: Bifidobacteria were shown more efficient than E. coli in carcasses samples. The presence of Bif. choerinum suggested a faecal pork contamination. Significance and Impact of the Study: Detection and identification of bifidobacteria, in correlation with E. coli counting, should improve hygiene quality of mutton processing chains. [less ▲]

Detailed reference viewed: 97 (19 ULg)