AOAC-RI ERP Micro June 2016

OMAMAN-29 A/ Collaboartive Study Manuscript OMA ERP June 2016 ERP Use Only

Results of Collaborative Study 1 2 For this collaborative study, the 3M Molecular Detection Assay (MDA) 2 - Listeria method was 3 compared to the USDA FSIS MLG 8.09 reference method for deli turkey and raw chicken breast 4 fillet. A total of 13 laboratories throughout the United Statesand Canada participated in this 5 study, with 11 laboratories submitting data for the deli turkey and 12 laboratories submitting data 6 for the raw chicken breast fillet. See Table 1 for a summary of laboratory participation for each 7 matrix. Each laboratory analyzed 36 test portions for each method per matrix: 12 inoculated 8 with a high level of Listeria , 12 inoculated with a low level of Listeria , and 12 un-inoculated 9 controls. 10 A background screen of the matrix indicated an absence of indigenous Listeria species in both 11 matrices.Ten (10) replicate test portions (randomly sampled from 50% of the total packages used 12 in the analysis) were screened for the presence of Listeria species. All test portions produced 13 negative results for the target analyte. 14 Results for the heat stress analysis of the inoculum for the deli turkey are presented in Table 2. 15 Table 2016.1A and 2016.1B summarize the inter-laboratory results for all foods tested, including 16 POD statistical analysis. As per criteria outlined in Appendix J of the AOAC Validation 17 Guidelines, fractional positive results were obtained.Detailed results for each laboratory are 18 presented in Tables 2016.2A and 2016.2B. For each matrix, the level of Listeria was determined 19 by MPN on the day of initiation of analysis by the coordinating laboratory. MPN results are 20 presented in Tables 2016.2A and 2016.2B.The individual laboratory and sample results are 21 presented in Tables 1-2 of the Supplementary Materials. The APCresults for each collaborating 22 are presented in Table3 of the Supplementary Materials. 25 26 Deli turkeytest portions were inoculated at a low and high level and were analyzed for the 27 detection of Listeria spp. Un-inoculated controls were included in each analysis. Laboratories 8 28 and 10 received test portions but were unable to conduct the analysis and therefore no data was 29 submitted. All other laboratories submitted data for both methods evaluated. The MPN levels 30 obtained for this matrix, with 95% confidence intervals, were 0.63 CFU/test portion (0.49,0.80) 31 for the low inoculum level and 4.52 CFU/test portion (3.19, 6.42) for the high inoculum level. 32 For the low inoculum level, 68 out of 132 test portions (POD CP of 0.52) were reported as 33 presumptive positive by the 3M MDA 2 – Listeria method with 66out of 132 test portions 34 (POD CC of 0.50) confirming positive. For samples that produced presumptive positive results on 35 the 3M MDA 2 – Listeria method, 66out of 132 samples confirmed positive (POD C of 0.50). For 36 test portions evaluated by the USDA/FSIS MLG reference method, 60 out of 132 test portions 37 produced positive results. A dLPOD C value of 0.04 with 95% confidence intervals of 38 (-0.08, 0.17) was obtained between the candidate and reference method, indicating no statistical 39 significant difference between the two methods. A dLPOD CP value of 0.02 with 95% confidence 40 intervals of (-0.11, 0.14) was obtained between presumptive and confirmed results indicating no 41 statistically significant difference between the presumptive and confirmed results. 42 AOAC Rese rch Institute Expert Review Panel Use Only 23 24 Deli Turkey (125 g Test Portions)

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