EVALUATION OF METHODS FOR THE ISOLATION AND DETECTION OF ESCHERICHIA-COLI O157 IN MINCED BEEF

This study has evaluated enrichment and detection procedures for the i solation and detection of Escherichia coli O157 inoculated into minced beef. The use of a 24 h enrichment in modified EC broth containing no vobiocin allowed low numbers of contaminating cells to multiply to lev els detectable on culture media and by ELISA test kits. Total analysis time was reduced by the use of the Dynabead(TM) immunomagnetic separa tion system. The use of the Petrifilm(TM) Test Kit-HEC for E. coli O15 7:H7 and Organon Teknika EHEC-TEK system detected low numbers of conta minating cells following enrichment and reduced analysis time by 1 d. The incorporation of cefixime and tellurite into Sorbitol MacConkey Ag ar increased the rate and ease of isolation off. coli O157 and its use is therefore recommended.