RI-ERP-FINALACTION-Recommendations

OMA 2015.13: Collaborative Study Protocol Expert Review Panel Use Only September, 2017

squares and determining the average number per square. Multiply the average number by 30 to determine the estimated count per plate. High concentrations of colonies on the 3M Petrifilm RAC Plates will cause the entire growth area to become blue or red. Occasionally, on overcrowded 3M Petrifilm RAC Plates, the center may lack visible colonies, but many small colonies can be seen on the edges. When any of these occurs, record results as too numerous to count (TNTC). Where necessary, colonies may be isolated for further identification. Lift the top film and pick the colony from the gel. Test using standard procedures.

Reporting Raw Data Report data using the electronic spreadsheet supplied by the study sponsors (Appendix 8.2). Upon completion of each food type, the laboratory will fax or email the completed data form to the co-Study Director. Copies of all data sheets should be retained by the collaborating labs for a minimum of one year. Analyzing Raw Data Average duplicate plates for the 3M Petrifilm RACPlate method and duplicate plates for the reference method. Convert counts into logarithms for data analysis. Calculate the repeatability (s r ) of the 3M Petrifilm RAC method and the reference methods by determining the mean of the logarithm (base 10) of the counts and the standard deviation, s r ,for each contamination level of each matrix. Calculate the reproducibility (S R ) of the 3M Petrifilm RAC method replicates at each concentration for each matrix across all laboratories. Report the mean difference between the candidate and reference method transformed results and its 95% confidence interval. Report the reverse transformed mean difference and confidence interval in CFU/unit. Appendices Instructions to Collaborators Data Report Forms Study Materials Study flow diagram – raw easy peel shrimp (50g) Study flow diagram – pasteurized skim milk (11mL), instant non-fat dried milk (11g) AOAC Research Institute

Expert Review Panel Use Only