EVALUATION OF METHODS FOR THE ISOLATION A ND DETECTION OF ESCHERICHIA-COLI O157-H7 FROM MINCED BEEF

This study has evaluated enrichment and detection procedures for the i solation and detection of Escherichia coli O157: H7 inoculated into mi nced beef, i.e., 24 hr enrichment in modified EC broth containing novo biocin (mEC+n) followed by plating onto sorbitol IPA bile salt agar (S IE), sorbitol MacConkey agar (SMAC), cefixime-tellurite SMAC (CT-SMAC) and Rainbow O157 agar, or immunomagnetic separation (IMS) followed by plating onto these four kind of media. The recovery of E. coli O157: H7 was greater on CT-SMAC than SMAC, SIE or Rainbow O157 Agar. The pro tocol using mEC+n incubated at 42 degrees C, followed by IMS and inocu lation onto CT-SMAC was the most succesful procedure. However, 24 hr e nrichment in mEC+n followed by CT-SMAC was almost as effective as the IMS method for the isolation of E. coli O157: H7.