Investigation of e. coli O157-H7 from lettuces consuming in aydin province

Escherichia coli O157:H7 is one of important foodborne patogens for public health. In this study, the presence of E. coli O157:H7 in the lettuce samples taken from neighborhood markets and supermarkets were investigated, isolation and identification of the agent were made. Hence, data of the prevalance and contamination status of the subjected pathogen for other regions of Turkey which have similar climate conditions was also aimed. The fresh lettuce samples investigated in this study were collected 100 pieces from neighborhood markets and supermarkets. The collected samples were brought to Adnan Menderes University Faculty of Veterinary Medicine Department of Microbiology Laboratory in cold chain. 25 g of lettuce was homogenized in 225 ml of mTSB and incubated for preenrichmentat 37±0,5°C for 24 h in order to detect E. coli O157:H7 bacteria. At the end of incubation period, the samples were inoculated to SMAC Agar (Sorbitol MacConkey Agar,) medium and incubated at 35-37°C for 18-24 h. The colonies that grew on CT-SMAC agar and sorbitol negative ones were inoculated to Fluorocult E. coli O157:H7 agar. The susceptible colonies were examined with pouring 1 ml of Kovacs reagent for confirmation. Latex agglutination tests were made for confirmation also. A a result of isolation and identifiaction procedures, 17 (17 %) E. coli O157:H7 strains were identified from collected lettuce samples. 12 (12 %) of the samples were detected from the samples of neighborhood markets and 5 (5 %) of the samples were detected from the samples of supermarkets. According to results, it is pointed that the lettuce obtained from neighborhood markets and supermarkets carry a risk for presence of E. coli O157:H7, and it is seen that preventive precaoutions have to be performed for fertilizing, harvesting, watering and storing points.