AOAC-RI ERP Micro June 2016

OMAMAN-30 A/ Collaborative Study Manuscript OMA ERP June 2016 ERP Use Only

Receipt Confirmation form provided and fax or email it back to the study director.The shipment 1 and hold timesof the inoculated test material had been verified as a quality control measure prior 2 to study initiation. 5 6 Collaborators were instructed to follow the appropriate preparation and analysis as outlined in 7 the study protocol for each matrix for both the 3M MDA 2 - Listeria monocytogenes method and 8 reference method. For both matrices, each collaborator received 72 test portions (12 high, 12 low 9 and 12 un-inoculated controls for each method to be performed). For the analysis of the deli 10 turkey test portions by the 3M MDA 2 - Listeria monocytogenes method, a 125 g portion was 11 enriched with 975 mL of Demi-Fraser (DF) with ferric ammonium citrate (FAC) broth, 12 homogenized for 2 minutes and incubated for 24-28 hours at 37 ±1 o C. For the raw chicken 13 breast fillettest portions analyzed by the 3M MDA 2 - Listeria monocytogenes method, a 25 g 14 portion was enriched with 475 mL of DF, homogenized for 2 minutes and incubated for 28-32 15 hours at 37 ±1 o C. 16 Following enrichment, samples were assayed by the 3M MDA 2 - Listeria monocytogenes 17 method and, regardless of presumptive result, confirmed following the USDA/FSIS MLG 8.09 18 reference method. Both matrices evaluated by the 3M MDA 2 - Listeria monocytogenes method 19 were compared to samples analyzed using the USDA/FSIS MLG 8.09 reference method in an 20 unpaired study design. All positive test portions were biochemically confirmed by the API 21 Listeria monocytogenes biochemical test or by the VITEK 2 GPbiochemical identification test, 22 AOAC Official Method 2012.02 [8]. 25 26 Each collaborating laboratory recorded results for the reference method and the 3M MDA 2 - 27 Listeria monocytogenes method on the data sheets provided. The data sheets were submitted to 28 the study director at the end of each week of testing for statistical analysis. Data for each matrix 29 was analyzed using the probability of detection (POD)statistical model [9]. The probability of 30 detection (POD) was calculated as the number of positive outcomes divided by the total number 31 of trials. The POD was calculated for the candidate presumptive results, POD CP, the candidate 32 confirmatory results (including false negative results), POD CC , the difference in the candidate 33 presumptive and confirmatory results, dLPOD CP, presumptive candidate results that confirmed 34 positive (excluding false negative results), POD C, the reference method, POD R , and the 35 difference in the confirmed candidate and reference methods, dLPOD C . A dLPOD C confidence 36 interval not containing the point zero would indicate a statistically significant difference between 37 the 3M MDA 2 - Listeria monocytogenes and the reference methods at the 5 % probability level. 38 In addition to POD, the repeatability standard deviation (s r ), the among laboratory repeatability 39 standard deviation (s L ), the reproducibility standard deviation (s R )and the P T value were 40 calculated. The s r provides the variance of data within one laboratory, the s L provides the 41 difference in standard deviation between laboratories and the s R provides the variance in data 42 between different laboratories. The P T value provides information on the homogeneity test of 43 laboratory PODs [10]. AOAC Research Institute Expert Review Panel Use Only 3 4 Test Portion Analysis 23 24 Statistical Analysis

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