Validation of the 3M™ Molecular Detection Assay 2-STEC Gene Screen (stx) for the Detection of Shiga Toxin Gene (stx1 and/or stx2) in Additional Matrixes: AOAC Performance Tested MethodSM 071903

Background The 3M (TM) Molecular Detection Assay 2 - STEC Gene Screen (stx) method is based on gene amplification by the use of real-time loop-mediated isothermal amplification when used with the 3M Molecular Detection System for the rapid and specific detection of Shiga toxin gene (stx1 and/or stx2) from Shiga toxin-producing enterohemorrhagic Escherichia coli (STEC) in enriched foods. Objective The 3M Molecular Detection Assay 2 - STEC Gene Screen (stx) method was evaluated as a Level 2 method modification to add new matrixes to the certified claim: 25 g fresh raw ground beef (approximately 75% lean), 375 g raw beef trim (approximately 75% lean), 375 g fresh raw ground pork (approximately 70% lean), 375 g fresh raw poultry parts, and 25 g sprouts. Methods Matrix studies were conducted to assess the method's performance compared to the US Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, 5C.00 for meat and poultry, and to the US Food and Drug Administration Bacteriological Analytical Manual, Ch. 4A for sprouts, using an unpaired study design. Results The 3M Molecular Detection Assay 2 - STEC Gene Screen (stx) method demonstrated no significant differences between presumptive and confirmed results or between candidate and reference method results for any of the matrices tested.