4. AOACRIMicroMethods-2018Awards

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B ird et al .: J ournal of AOAC I nternational V ol . 99, N o . 3, 2016  673

Figure 6. Youden plot for combined mean 3M Petrifilm RAC Plate and FDA BAM results for raw easy-peel shrimp evaluated at 35°C.

However, no evidence of physical cause or suspicion of cause was noted and it was determined that the data would be included in the statistical analysis. There were no statistically significant differences between the 3M Petrifilm RAC Plate and SMEDP methods as determined by the 95% CI of the differences of means at any of the three contamination levels.

to “vibrant colony color and intensity” observed during the evaluation. For the instant NFDM, several laboratories indicated the 3M Petrifilm RAC plates prevented colonies from producing spreader colonies, which had occurred on the reference method agar plates. This allowed for easier enumeration on the 3M Petrifilm RAC plates than the reference method agar plates. Additionally, one laboratory indicated, “For laboratories working with dairy products or with products that contain high levels of Bacillus , the RAC plates would provide a significant benefit.” During the analysis of the pasteurized skim milk, two laboratories indicated deviations from the approved protocol and did not submit data for statistical analysis. Laboratory 7 received their test portions after 48 h from the initial shipment from the coordinating laboratory. The temperature control indicated that the samples were outside the acceptable range, however, the

Discussion

No negative feedback was reported to the study directors from the collaborating laboratories in regards to the performance of the 3M Petrifilm RAC Plate. Several laboratories indicated that the colonies were more easily identified on the 3M Petrifilm RAC plates then on the reference method agar plates due

Figure 7. Youden plot for combined mean 3M Petrifilm RAC Plate and SMEDP results for pasteurized skim milk.

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