DETECTION AND OCCURRENCE OF VEROTOXIN-FOR MING AND OR SHIGATOXIN-FORMING ESCHERICHIA-COLI (VTEC AND/OR STEC) IN MILK/

Raw milk contaminated with VTEC was described as a source of human EHE C infection. Diagnosis of VTEC from milk is complicated by the low num ber of VT-positive cells in the total bacterial count, the great varie ty of serovars with different combinations of virulence markers and th e lack of characteristic biochemical properties for the cultural detec tion of all VTEC. The graduated procedure presented and used for the e xamination of milk samples is based on VT detection in suitable enrich ment cultures and the selective isolation of VTEC by means of VT-speci fic monoclonal antibodies using the VT-colony immunoblot. This method was used to examine 127 samples of raw milk and 146 samples of certifi ed raw milk (Vorzugsmilch) from 5 different regions in Germany. 3.9% o f the raw milk samples and 2.1% of the certified milk samples were VTE C-positive. Except for one O157:H-isolate from a raw milk sample, the VTEC found belonged to the group of non-O157 VTEC. They were assigned to 5 different serovars with different combinations of virulence marke rs. Therefore, raw milk and certified raw milk will continue to presen t a potential source of EHEC infection. It is recommended to use the p rocedure presented for the elucidation of the route of infection and f or the improvement of detection of VTEC and EHEC-strains in milk in or der to obtain comparable data for diagnosis in the official food contr ol laboratories of the federal lands.