EZ COLI RAPID DETECTION SYSTEM - A RAPID METHOD FOR THE DETECTION OF ESCHERICHIA-COLI O157 IN MEAT AND OTHER FOODS

The EZ Coli(TM) Rapid Detection System consists of a selective enrichm ent medium and a rapid immunological detection kit. After being incuba ted for 15 to 24 h at 40 to 42 degrees C, an Escherichia coli 0157 cul ture was at a sufficient cell concentration (> 10(6) CFU/ml) to be tes ted with the EZ Coli Detection Kit. In studies of foods seeded with E. coli 0157, all 42 strains of E. coli 0157 tested positive with the de tection kit. None of the 29 strains of E. coli non-0157 tested positiv e with the kit. Species of Citrobacter, Hafnia, and Klebsiella grew in the medium but tested negative. Of the 47 strains of non-E. coli 0157 tested, only two strains of Salmonella O Group N grew and tested posi tive with the kit. Several laboratories evaluated the EZ Coli System w ith 378 clean and naturally contaminated food samples (mainly raw beef ), and 337 different food samples, including raw meats (beef, pork, tu rkey, and chicken), dairy products, spices, vegetables, and apple cide r, spiked with 50 different strains of E. coli 0157 (1 to 100 CFU/25 g ). Of these samples, 44.6% were positive and 52.2% were negative. The false-positive rate was 1.7% and the false-negative rate was 1.5%. The data show that high levels of coliforms (> 10(6) CFU/g) in food sampl es may impede the detection of low levels (1 to 10 CFU/25 g) of E. col i 0157 organisms in broth, thereby causing false-negative reactions wi th most detection systems. The EZ Coli Rapid Detection System provides a rapid and specific means of detecting E. coli 0157 in raw and proce ssed foods.