Incidence of toxigenic Escherichia coli in soft cheese made with raw or pasteurized milk

Soft cheeses made with raw (221 samples) or pasteurized (75) cow's milk were collected. Enterotoxigenic, verotoxigenic and necrotocigenic Escherichia coli strains were studied. Three raw milk cheeses were positive for toxigenic E. coli (1·4%) : the first with toxin CNF2 and serogroup O5 (40% of colonies studied with typical E. coli morphology) ; the second with VT and O2 (10%) ; and the third with LT and O51 (10%). Toxigenic E. coli of bovine origin can pass to the milk destined to make cheese, and survive. Soft cheese should be considered as a possible vehicle of infection in future investigations.