Evaluation of methods for detection of Escherichia coli O157:H7 in milk, and occurrence of E-coli O157: H7 in ex-farm raw milks in Hungary

The purpose of this study was to evaluate the efficacy of classical protocols and an automated immunoassay system (Mini-VIDAS) for detection of Escherichia coli O157:H7 in milk. In addition, the incidence of E. coli O157:H7 in Hungarian ex-farm raw milks was also determined. The results showed that the Mini-VIDAS E. coli O157 (ECO) system was superior to conventional methods, with sensitivity, specificity, and accuracy percentages of 100, 97.9, and 99.3, respectively. Two hundred and fifty ex-farm raw milk samples were tested in Mini-VIDAS-ECO and concurrently by a traditional protocol, US Food and Drug Administration Bacteriological Analytical Manual Method C. The latter method gave 65 negative and 185 uncertain results, which required further identification, whereas the Mini-VIDAS-ECO gave 1 positive and 249 negative results. With both methods, only 1 out of 250 samples tested was finally confirmed positive. In conclusion, Mink VIDAS-ECO proved to be a potent tool for detection of E coli O157:H7 in raw milk. With this system, 0.4% of Hungarian farm raw milk samples were found to contain E coli O157:H7.