Les entérocoques dans les fromages : une menace discutable pour quelques consommateurs à risque, une amélioration possible de la qualité des fromages au lait cru... ou pasteurisé
Enterococci in cheese: a debatable menace for certain `'at risk'' consumers, a possible improvement in the quality of raw and pasteurised-milk cheeses. Due to their normal and inevitable presence in raw milk, as well as to their thermo-resistance and resistance to lactic acid, enterococci are found in all types of cheese, at levels ranging from several thousands to tens of millions per gram. When enterococci are incorporated into lactic starters, either in order to improve the taste of certain cheeses, or to inhibit Listeria (by using bacteriocin-producing strains), numbers up to 109 cells per gram can be reached. Enterococci do not satisfy all the criteria required to be considered as indicators of faecal contamination of milk. On the other hand, it seems easy to select mutants which do not produce biogenic amines. The objection by medical doctors to the presence of enterococci in foods arises from the fact that these bacteria often contain genes coding for the resistance to antibiotics used in human therapy. These genes are usually located on plasmids which are easily transferable to pathogenic bacteria passing through the intestine. The question therefore is to know whether the strains responsible for nosocomial infections come directly from foods, or from previous implantation in the intestine. Nevertheless, it would seem quite impossible to completely eliminate enterococci from either source.
Jean A. RICHARD