ERP Micro December 2019

Caution: When the assay is completed, handle and dispose of all waste as a biohazard. Never, under any circumstances, open amplification tubes after the amplification process has started to prevent discharge of amplified materials into the laboratory which could cause contamination of the testing environment. G. Confirmation of Positive Results Following 8 – 18 h enrichment in mEHEC® at 42 °C (10 – 18 h for 375 g samples), samples can be confirmed from the retained mEHEC® enrichment via the following: 1) Modified U.S. Department of Agriculture (USDA) Microbiology Laboratory Guidebook (MLG 5C.00) 2) Modified U.S. Food and Drug Administrative Bacteriological Analytical Manual (BAM Chapter 4A) 3) Assurance® GDS Shiga Toxin Genes Tq kit (Cat. No. 71005-100) 4) Assurance® GDS EHEC ID for E . coli O157:H7 Tq kit (Cat. No. 71037-52) Note : Enriched samples can be stored at 5 ± 3°C (refrigeration) for up to 24 h prior to confirmation.

Reference: J. AOAC Int . 88 , 1334(2005).

Matrix Extension for frozen finely textured beef, carcass cloths and green onions

Results Matrix Studies

No natural contamination was detected in the screening of these products; therefore, each matrix was artificially contaminated with E. coli O157:H7 (see Preparation of Inoculum and Test Portions , above). As per criteria outlined in Appendix J of the Official Methods of Analysis Manual , fractional positive results were obtained for both confirmation methods of the 18 h enrichment for the GDS EHEC method (see Test Portion Analysis , above). A summary of the method comparison result PODS is presented in Table B and Table C , below.

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