Purpose: To evaluate the Atlas STEC Detection Assay for the detection of E. coli O157:H7 and STECs in artificially inoculated ground beef and beef trim after a single enrichment of 375 g test portions.
Methods: The method included a single enrichment of 375 g test portions in modified Tryptic Soy Broth (mTSB) at 42°C. After sample transfer for bacterial lysis, template specific sample extraction, amplification and probe detection were all performed on the automated instrument. Fresh raw ground beef, 30% fat, and fresh raw beef trim were compared to the FSIS MLG 5.06 and 5B.02 confirmation procedures. Selectivity was evaluated by testing 50 target microorganisms and 30 non-target microorganisms as determined by POD analysis.
Results: The test method provided a positive result for 100% of 50 target microorganisms, and a negative result for 30 non-target microorganisms. No significant differences were observed between the test method and the FSIS MLG 5.06 and 5B.02 confirmation methods.
Significance: E. coli O157:H7 and STEC, including the FSIS regulated big six serogroups, can be detected in raw ground beef and beef trim on the Atlas System.