DETECTION OF PATHOGENIC YERSINIA-ENTEROCOLITICA IN MILK AND PORK USING A DIG-LABELED PROBE TARGETED AGAINST THE YST GENE

A PCR-amplified, digoxigenin (DIG)-labelled yst probe was evaluated in naturally and artificially contaminated pork and milk samples for its ability to detect and differentiate between pathogenic and nonpathoge nic strains of Yersinia enterocolitica following enrichment in irgasan -ticarcillin-chlorate (ITC) enrichment broth. A total of 44 raw pork s amples were obtained from one meat-processing factory and two local re tail stores. Y. enterocolitica serogroup O:3/biovar 4 was isolated fro m 6 of the 44 (14%) pork samples tested. The hybridization results wer e in good agreement when compared with those from standard biochemical and serological tests. The lowest concentration detectable by a colon y hybridization technique in the milk samples inoculated with Y. enter ocolitica O:8 PA-A corresponded to 10 cfu/ml in the original sample. N o pathogenic serovars were detected in 6 raw milk and 3 pasteurized mi lks tested. The results of this investigation demonstrate that the DIG -labelled yst probe is a reliable tool for rapid detection of pathogen ic Y. enterocolitica in naturally and artificially contaminated food s amples. (C) 1997 Elsevier Science B.V.