Evaluation of methods for the isolation and detection of Escherichia coli O157 in minced beef

A.R. BENNETT, S. MACPHEE AN D.R.P. BETTS. 1995. This study has evaluated enrichment and detection procedures for the isolation and detection of Escherichia coli 0157 inoculated into minced beef. The use of a 24 h enrichment in modified EC broth containing novobiocin allowed low numbers of contaminating cells to multiply to levels detectable on culture media and by ELISA test kits. Total analysis time was reduced by the use of the Dynabead TM immunomagnetic separation system. The use of the PetrifilmTM Test Kit-HEC for E. coli 0157 : H7 and Organon Teknika EHEC-TEK system detected low numbers of contaminating cells following enrichment and reduced analysis time by 1 d. The incorporation of cefixime and tellurite into Sorbitol MacConkey Agar increased the rate and ease of isolation of E. coli O157 and its use is therefore recommended.