4. AOACRIMicroMethods-2018Awards

B ird et al .: J ournal of aoaC i nternational V ol . 99, n o . 4, 2016 991

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Figure 2016.01A.

method for raw ground beef and to the FDA BAM reference method for creamy peanut butter. A total of 16 laboratories throughout the United States participated in the study, with 13 laboratories submitting data for raw ground beef and creamy peanut butter. See Table 1 for a summary of laboratory participation for each matrix. Each laboratory analyzed 36 test portions for each method per matrix: 12 inoculated with a high level of Salmonella , 12 inoculated with a low level of Salmonella , and 12 uninoculated controls. A background screen of the matrix indicated an absence of indigenous Salmonella spp. in both matrixes. Due to the amount of raw ground beef needed for the evaluation (about1000 lb), 10 replicate 325 g test portions (prepared by compositing 65 g from over 50% of the total packages used in the analysis) were screened for Salmonella spp. All test portions produced negative results for the target analyte. For creamy peanut butter, 10 replicate test portions (randomly sampled from 50% of the total packages used in the analysis) were screened for the presence of Salmonella spp. All test portions produced negative results for the target analyte. Results for the heat stress analysis of the inoculum for the creamy peanut butter are presented in Table 2. The individual laboratory and sample results are presented in Tables 3 and 4. Tables 2016.01A and 2016.01B summarize Table 1. Participation of each collaborating laboratory a Laboratory Raw ground beef Creamy peanut butter 1 Y Y 2 Y Y 3 Y Y b 4 Y Y 5 Y c Y c 6 Y Y 7 N Y b 8 Y Y 9 Y Y 10 N Y 11 Y Y c 12 Y Y 13 Y Y 14 Y Y 15 Y Y 16 Y N a Y = Collaborator analyzed the food type; N = collaborator did not analyze food type. b Results were not used in statistical analysis due to laboratory error. c Results were not submitted to the coordinating laboratory.

Figure 2016.01B.

(i) After the assay is complete, remove the 3M Molecular Detection speed loader tray from the 3M MDS instrument and dispose of the tubes by soaking in a 1–5% (v/v in water) household bleach solution for 1 h and away from the assay preparation area. Note: To minimize the risk of false positives due to cross- contamination, never open reagent tubes containing amplified DNA. This includes RC, reagent, and matrix tubes. Always dispose of sealed reagent tubes by soaking in a 1–5% (v/v in water) household bleach solution for 1 h and away from the assay preparation area. An algorithm interprets the light output curve resulting from the detection of the nucleic acid amplification. Results are analyzed automatically by the software and are color- coded based on the result. A positive or negative result is determined by analysis of a number of unique curve parameters. Presumptive positive results are reported in real time, whereas negative and “inspect” results will be displayed after the run is completed. Presumptive positive results should be confirmed using your preferred method or as specified by the FDA BAM, USDA/FSIS MLG, or ISO 6579 reference method, starting from the 3M primary enrichment, followed by transfer to a secondary enrichment or direct plating onto media through confirmation of isolates using appropriate biochemical and serological methods. Note: Even a negative sample will not give a zero reading because the system and 3M MDA 2 – Salmonella amplification reagents have a “background” relative light unit reading. In the rare event of any unusual light output, the algorithm labels this as inspect. 3M recommends the user to repeat the assay for any inspect samples. When the result continues to be inspect, proceed to the confirmation test using your preferred method or as specified by local regulations. J. Results and Interpretation

Results of Collaborative Study

For the collaborative study, the 3M MDA 2 – Salmonella method was compared to the USDA/FSIS MLG reference

03/10/2019