Coliforms, especially Escherichia coli, are one of the most important causes of gastroenteritis and microbial index of water and food contamination. Enterohemorrhagic Escherichia coli strains are considered to be the most important intestinal pathogens due to hemorrhagic diarrhea and hemolytic syndrome, of which E. coli O157: H7 is the most important and common. The purpose of this study was to investigate the prevalence of E. coli O157: H7 contamination in traditional and homemade ice creams and compare the efficiency of chromogenic media with standard media for its detection. In this study, 90 samples of traditional ice cream from the production and distribution centers of this product were collected from three urban regions of Bandar Abbas, in two warm and cold seasons and in order to count the coliforms and detect E. coli and E. coli O157: H7, two standard and chromogenic methods were used. The results indicated that 81.8% of samples had more than the standard number of coliforms, and 28.9% of the samples were contaminated with E. coli. E. coli O157: H7 contamination was detected 2.2% and 4.4% using standard and chromogenic methods, respectively. Analyzes showed that application of media containing chromogenic substances, E. coli O157: H7 could be detected with the least possible error. It was found that the use of chromogenic culture media to identify E. coli O157: H7 was better than the standard method. The results of the present study also indicate that the quality and health status of traditional and handmade ice creams should be more closely monitored.

Keywords: Escherichia coli O157: H7, Traditional ice cream, Chromogenic medium, Standard method

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