Escherichia coli O157:H7 is an important human pathogen causing haemorrhagic colitis, haemolyticuraemic syndrom and thrombotic thrombocytopenic purpura. In this study, 100 ground beef samples were collected randomly from beef markets in June 2004. For isolation of the bacteria, samples were firstly enriched in modified trypticase soy broth, followed by plating onto sorbitol MacConkey agar sup...