AOAC-RI ERP Micro June 2016

OMAMAN-29/OMAMAN-30 Combined Collaborative Study Protocol OMA ERP - June 2016 ERP Use Only

3M MDA 2 Listeria species and L. monocytogenes Collaborative Study OMA-2016-MONTH-XXX

6.0

Reporting Raw Data 6.1

Report data using the data report form in Appendix 9.2.

6.2

Upon completion of each food type, the laboratory will fax or email the completed data form to the Study Director.

6.3 Copies of all related test results (data sheets, printouts and confirmation results) should be retained by the collaborating labs for a minimum of one year. 7.0 Analyzing Raw Data The resulting data will be analyzed by probability of detection (POD). 7.1 Probability of Detection (POD) - POD is the proportion of positive analytical outcomes for a qualitative method for a given matrix at a given analyte level or concentration. POD is concentration dependent. Please see the revised microbiology guidelines 2 for complete analysis information on POD calculations. 7.1.1 Calculate: 7.1.1.1 Estimate of repeatability - standard deviation (s r ) 7.1.1.2 Determine POD values for each matrix and concentration - the number of positive outcomes divided by the total number of trials. 7.1.1.3 Estimate of reproducibility – standard deviation of the laboratory POD values (s POD ) and confidence intervals. 7.1.1.4 Cross laboratory probability of detection (LPOD) – LPODs by

matrix and concentration with 95% confidence intervals for candidate method (presumptive and confirmed) results. 7.1.1.5 Difference of cross-laboratory probability of detection (dLPOD) – difference probability of detection is the difference between any two LPOD values. 7.1.1.5.1 Estimate dLPOD C as the difference between the candidate and reference LPOD values, include CIs. 7.1.1.5.2 Estimate dLPOD CP as the difference between the presumptive and confirmed LPOD values, include CIs. 7.1.1.5.3 If the CI of a dLPOD does not contain zero then the difference is statistically significant . 7.1.1.6 For each matrix, graph POD R , LPOD C and dLPOD C by level with 95% confidence intervals. AOAC Research Institute Expert Review Panel Use Only

2 AOAC INTERNATIONAL Methods Committee Guidelines for Validation of Microbiological Methods for Food and Environmental Surfaces (pre-publication document, 2012) Sharon Brunelle, Robert LaBudde, Maria Nelson, and Paul Wehling

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