Anti-adhesive properties of bovine oligosaccharides and bovine milk fat globule membrane-associated glycoconjugates against bacterial food enteropathogens

The prevalence of the main raw milk and raw milk-derived dairy product enteropathogens (Campylobacter, Shiga toxin-producing Escherichia coli, Listeria, and Salmonella) is higher than the number of epidemiological cases related to ingesting these foodstuffs. Bovine milk oligosaccharides and milk fat globule membrane (MFGM)-linked glycoconjugates interact with food-borne enteropathogens to inhibit their adhesion to intestinal cells and tissues. This review examines the main mechanisms and strategies used by enteropathogens to adhere to their target. details the anti-adhesive properties of MFGM: against enteropathogens and enterotoxins, assesses the integrity of bacteria MFGM complexes during dairy product manufacture and digestion, and discusses the potential for using these macromolecules and glycoconjugates in foods for public health

Silage processing and strategies to prevent persistence of undesirable microorganisms

International audienceYear-round access to good quality forage is a physiological priority for ruminants and an economic priority for farmers. Ensiling is a method for preserving moist crops based on organic acid production by lactic acid bacteria under anaerobic conditions. However, silage can be a vector for undesirable microorganisms, impairing crop preservation, animal performance or the health of both animals and humans. Major problems in silage processing are due to failure to apply good manufacturing practice (GMP). To improve silage preservation and guarantee the quality of this animal feed, silage additives such as chemicals, enzymes and bacterial agents can be employed. The purpose of the present paper is to review existing information on the desirable and undesirable microorganisms involved in silage processing, and possible methods, using GMP or silage additives, of limiting silage degradation and its economic effects and health impact on animals and humans. (C) 2013 Elsevier B.V. All rights reserved

Molecular characterization of O157:H7, O26:H11 and O103:H2 shiga toxin-producing escherichia coli isolated from dairy products

Pathogenic Shiga toxin-producing E. coli (STEC) are recognized worldwide as environment and foodborne pathogens which can be transmitted by ingestion of ready-to-eat food such as raw milk-derived products. STEC show a prevalence rate in dairy products of 0.9%, yet comparably few outbreaks have been related to dairy products consumption. In this study, we used rt-qPCR to identify the virulence potential of 0157, 026 and 0103 STEC strains isolated from raw-milk dairy products by analyzing virulence-related gene frequencies and associations with O-island (OI) 44, 01-48, 01-50, 01-57, 01-71 and 01-122. Results showed that 100% of STEC strains investigated harbored genes associated with EHEC-related virulence profile patterns (eae and stx, with either espK, espy, ureD and/or Z2098). We also found similarities in virulence-related gene content between O157:H7 and O103:H2 dairy and non-dairy STEC strains, especially isolates from human cases. The O26:H11-serotype STEC strains investigated harbor the arcA-allele 2 gene associated with specific genetic markers. These profiles are associated with high-virulence seropathotype-A STEC. However, the low frequency of stx2 gene associated with absence of other virulence genes in dairy isolates of O26:H11 remains a promising avenue of investigation to estimate their real pathogenicity. All O26:H11 attaching-effacing E. coli (AEEC) strains carried CRISPRo26:rni SP 026E but not genetic markers espK, espy, ureD and/or Z2098 associated with the emerging potentially high -virulence "new French clone". These strains are potentially as "EHEC-like" strains because they may acquire (or have lost) stx gene. In this study, O157:H7, O103:H2 and O26:H11 STEC strains isolated from dairy products were assigned as potential pathogens. However, research now needs to investigate the impact of dairy product environment and dairy processing on the expression of their pathogenicity

Foodborne transmission of sorbitol-fermenting Escherichia coli O157:[H7] via ground beef: an outbreak in northern France, 2011

International audienceSorbitol-fermenting Escherichia coli O157:[H7] is a particularly virulent clone of E. coli O157:H7 associated with a higher incidence of haemolytic uraemic syndrome and a higher case fatality rate. Many fundamental aspects of its epidemiology remain to be elucidated, including its reservoir and transmission routes and vehicles. We describe an outbreak of sorbitol-fermenting E. coli O157:[H7] that occurred in France in 2011. Eighteen cases of paediatric haemolytic uraemic syndrome with symptom onset between 6 June and 15 July 2011 were identified among children aged 6 months to 10 years residing in northern France. A strain of sorbitol-fermenting E. coli O157:[H7] stx2a eae was isolated from ten cases. Epidemiological, microbiological and trace-back investigations identified multiply-contaminated frozen ground beef products bought in a supermarket chain as the outbreak vehicle. Strains with three distinct pulsotypes that were isolated from patients, ground beef preparations recovered from patients' freezers and from stored production samples taken at the production plant were indistinguishable upon molecular comparison. This investigation documents microbiologically confirmed foodborne transmission of sorbitol-fermenting of E. coli O157 via beef and could additionally provide evidence of a reservoir in cattle for this pathogen