Véronique Lafarge

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We monitored the dynamic changes in the bacterial population in milk associated with refrigeration. Direct analyses of DNA by using temporal temperature gel electrophoresis (TTGE) and denaturing gradient gel electrophoresis (DGGE) allowed us to make accurate species assignments for bacteria with low-GC-content (low-GC%) (<55%) and medium- or high-GC% (>55%)(More)
A study was carried out to estimate the proportion of diseases due to milk and milk products among food-borne diseases recorded in France and in other countries since 1980. Particular attention was given to whether the milk involved was heat-treated or not. Four etiologic agents were considered: Salmonella spp., Staphylococcus aureus, Listeria(More)
Numerous microorganisms, including bacteria, yeasts, and molds, constitute the complex ecosystem present in milk and fermented dairy products. Our aim was to describe the bacterial ecosystem of various cheeses that differ by production technology and therefore by their bacterial content. For this purpose, we developed a rapid, semisystematic approach based(More)
A new selective agar medium, ALOA, for the selective and differential isolation of Listeria monocytogenes has been evaluated. All stressed cultures of L. monocytogenes serovars tested grew on the medium as bluish colonies surrounded by a distinctive opaque halo and gave a productivity ratio of at least 0.95. Non-pathogenic Listeria sp. produced bluish(More)
According to the draft standard method, EN ISO 16654 for the detection of Escherichia coli O157 in foods, samples of milk products inoculated with E. coli O157 were cultured in modified Tryptone Soya Broth supplemented with novobiocin. After immuno-magnetic separation (IMS) of the micro-organisms with magnetic beads coated with an antibody against E. coli(More)
Enterobacter sakazakii is an occasional contaminant of powdered infant formula that can cause rare but severe foodborne infections in infants. To determine optimal methods for the detection and identification of E. sakazakii, 38 naturally contaminated samples from infant formulae factories were analyzed by two PCR-based methods and by a method (TS 22964/RM(More)
Milk and dairy products harbour a natural microbial flora and/or other micro-organisms, which vary within the wide range of products available on the French market. The origin of contamination by pathogenic bacteria varies with the type of product and the mode of production and processing. Contamination of milk and dairy products by pathogenic(More)
The influence of supplementing the culture medium with magnesium sulphate, D-glucose, L-cysteine, catalase or lithium chloride, of incubation temperature and of oxygen availability on the recovery of salt- or acid-damaged Listeria monocytogenes, was studied on a solid repair medium according to a Hadamard matrix, with seven parameters varying between a high(More)
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