4. AOACRIMicroMethods-2018Awards

782  B ird et al . : J ournal of AOAC I nternational V ol . 98, N o . 3, 2015 Figure 1: 3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 Results for Frozen Raw Ground Beef Patties Incubated at 25 o C and Enumerated at 48 and 60 Hours

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Figure 3: 3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 Results for Raw Almonds Incubated at 25 o C and Enumerated at 48 and 60 Hours

3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 for Raw Ground Beef Incubated at 25 o C

3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 for Raw Almonds Incubated at 25 o C

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Frozen Raw Ground Beef Patties 25C Enumerated at 48 Hours Frozen Raw Ground Beef Patties 25C Enumerated at 60 Hours

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Log10 FDA BAM/ISO 21527 CFU/g Results

Log1 3M RYM CFU/g Results

Log1 3M RYM CFU/g Results

Figure 1. 3M Petrifilm RYM Count Plate versus FDA BAM/ISO 21527 results for frozen raw ground beef patties incubated at 25°C and enumerated at 48 and 60 h. Figure 2: 3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 Results for Frozen Raw Ground Beef Patties Incubated at 28 o C and Enumerated at 48 and 60 Hours

Figure 3. 3M Petrifilm RYM Count Plate versus FDA BAM/ISO 21527 results for raw almonds incubated at 25 ° C and enumerated at 48 and 60 h. Figure 4: 3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 Results for Raw Almonds Incubated at 28 o C and Enumerated at 48 and 60 Hours

3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 for Raw Ground Beef Incubated at 28 o C

3M Petrifilm RYM Count Plate vs. FDA BAM/ISO 21527 for Raw Almonds Incubated at 28 o C

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solidify in the 3M Petrifilm RYM Count Plate medium. Several laboratories also indicated that the colonies were very easy to interpret due to their size and color. One laboratory indicated that the “Space saving benefits of Petrifilm over the traditional FDA BAM method are readily apparent.” During the analysis of samples, several laboratories indicated deviating from the approved protocol and therefore, their data was subsequently removed from statistical analysis. No laboratories were removed from statistical analysis as a result of their data. For the raw ground beef, four laboratories were removed from statistical analysis. Laboratory 12 was unable to enumerate samples by both the 3M Petrifilm RYM Count Plate method and reference methods on the same day. All samples were plated onto DRBC, then stored at 2–8°C overnight and plated onto the Petrifilm RYM plates the following day. Laboratories 6 and 8 prepared the reference method samples using duplicate plating and not the required triplicate plating. Laboratory 4 (for both raw ground beef and raw almonds) failed to enumerate the 3M Petrifilm RYM Count Plates at the 60 h time point. Due to these deviations, these laboratories were removed from statistical analysis. There were no statistically significant differences at the 5% level in log transformed means between the 3M Petrifilm RYM Count Plate method and FDA BAM/ISO 21257 methods for either matrix evaluated in this study, at any of the three contamination levels. No statistically significant differences were observed between the 3M Petrifilm RYM Count Plate results when enumerated at 48 h versus 60 h and compared to the FDA BAM/ISO 21527 methods. No statistically significant differences were also observed between 3M Petrifilm RYM Count Plates that were incubated at 25°C and 28°C when compared to the FDA BAM/ISO 21527 methods. Based on the data presented, the s r values obtained at all incubation conditions and for all three contamination levels were generally similar between the two methods. Figure 2. 3M Petrifilm RYM Count Plate versus FDA BAM/ISO 21527 Results for frozen raw ground beef patties Incubated at 28 ° C and Enumerated at 48 and 60 h.

Figure 4. 3M Petrifilm RYM Count Plate versus FDA BAM/ISO 21527 results for raw almonds incubated at 28 ° C and enumerated at 48 and 60 h.

For raw frozen ground beef patties and raw almonds, the 3M Petrifilm RYM Count Plate method was more repeatable than the FDA BAM/ISO 21527 reference methods for one of the six contamination levels analyzed at 25°C and four of the six contamination levels analyzed at 28°C.

Recommendations

It is recommended that the 3M Petrifilm Rapid Yeast and Mold Count (RYM) Plate method be adopted as Official First Action status for the enumeration of yeast and molds in the following high water activity matrixes: yogurt (1.5% fat), frozen bread dough, fermented salami, sour cream, ready-made pie, raw frozen ground beef patties (77%), ready-to-eat deli sandwiches, sliced apples, and the following low water activity matrixes: raw almonds and dehydrated soup. We would like to extend a sincere thank you to the following collaborators for their dedicated participation in this study: Dave Metzger, Wendy Lee, and Thomas Hirsch, Accelerated Analytical, Milwaukee, WI Peyman Fatemi and Sharon Spencer, Aemtek, Inc., Fremont, CA Joel Blumfield, EDL Labs, Inc., Purvis, MS Bryan Dieckleman, Eurofins Microbiology Laboratories, Inc., Des Moines, IA Karilyn Gonzales and Chelsea Fagundes, Food Microbiological Laboratories, Inc., Cypress, CA Jerry Reed and Jeraldine Medellin, Metrix 360 Laboratories, San Antonio, TX Adam Hankins, McCoy and McCoy Laboratories, Inc., Madisonville, KY Acknowledgments

03/10/2019