PREVALENCE OF SHIGA TOXIN PRODUCING ESCHERICHIA COLI (STEC) IN MILK AND SOME DAIRY PRODUCTS

Two hundred & eighty samples [100 samples of raw milk, 50 samples of ice cream, 30 samples of plain yogurt and 100 samples of cheese (25 each of soft, hard, processed and Kariesh)] were randomly collected from dairy farms, dairy shops & groceries in Cairo and Giza governorates. Coliforms could be detected in 96%, 58%, 50%, 80%, 84%, 72 % and 60% of raw milk, ice cream, plain yogurt, Kariesh cheese, soft cheese, hard cheese and processed cheese samples, respectively. E. coli and other species of coliform could be detected in the examined samples at varying percentages. the incidence of Enterohaemoragic Escherichia coli by using MUG test were 22.60%, 30%, 25%, 25%, 66.67%, 57.14% and 42.86% of the examined samples of raw milk, ice cream, plain yogurt, Kariesh cheese, soft cheese, hard cheese and processed cheese, respectively. Shigtoxigenic E. coli could be serologically identified which belonged to O157, O78, O103, O118, O124, O145 and O164, it was evident that shiga toxins could be detected using ELISA test in raw milk, ice cream, Kariesh cheese and processed cheese samples with incidence of 4%, 2%, 4% and 4%, respectively. By using PCR technique, shiga toxin (Stx2) gene was confirmed in 1% of the examined raw milk samples.