Verotoxic Escherichia coli (STEC) from beef and its products.

In the present investigation, out of 27 (24.10%) strains of Escherichia coli isolated from 112 beef samples comprising raw meat (45), kabab (36) and kofta (31), 9 (33.33%) belonging to 7 different serotypes were verotoxic as tested by vero cell cytotoxic assay. Serotype O145 was the predominant STEC in raw meat. Interestingly, one STEC-O157 strain was also detected. All the STEC strains were positive for Stx genes by polymerase chain reaction showing stx2 (77.78%) to be most predominant followed by stx1 (22.22%). Phenotypic enterohaemolysin production on washed sheep blood agar supplemented with CaCl2 revealed 6 (66.67%) STEC strains to be positive. Presence of STEC in cooked beef products, viz., kabab and kofta appeared to be a matter of concern and potential threat to public health.