# AOAC ISPAM Stakeholder Panel Meeting Book 9-24-17

Quantitative Microbiology Validation Acceptance Criteria

Original Statistics - Log 10 transform data • Can’t be performed for Uninoculated Control Level (0 Data Points) Perform ANOVA or t-test to determine if mean replicates at each level are different Calculate repeatability by determining the standard deviation (s r ) at each level Graph the mean results for each contamination level (Candidate – Y axis, reference – X axis) and determine the slope and linear correlation coefficient (r 2 )

Acceptance Criteria per matrix per level was established • p value (obtained from ANOVA or t-test) should be >0.05 to establish equivalence between methods

Quantitative Microbiology Validation Acceptance Criteria

Revised Appendix J Guidelines Log 10

transform data using updated equation

Log 10 [CFU/unit + (0.1)f] f is the reported CFU/unit corresponding to the smallest reportable result

Modification to Log 10

transformation is to normalize the data and can be

used to evaluate uninoculated control levels (data results with 0) Plot all data, candidate (Y axis) vs. reference (X axis) – Identify outliers Perform outlier tests (Cochran and Grubbs) - What does the outlier mean? If data is an outlier can you exclude? How to report them? Calculate repeatability/standard deviation (s r ) and reproducibility (Collaborative study only) Additional requirement for OMA methods is to construct a Youden Plot

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