4. AOACRIMicroMethods-2018Awards

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B ird et al .: J ournal of AOAC I nternational V ol . 98, N o . 3, 2015  767

FOOD BIOLOGICAL CONTAMINANTS

Evaluation of the 3M ™ Petrifilm ™ Rapid Yeast and Mold Count Plate for the Enumeration of Yeast and Mold in Food: Collaborative Study, First Action 2014.05 P atrick B ird , J onathan F lannery , E rin C rowley , J ames A gin , and D avid G oins Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214 R obert J echorek 1 3M Food Safety Department, 3M Center – Bldg. 260-6B-01, St. Paul, MN 55144 Collaborators: K. Beers, J. Blumfield, R. Brooks, B. Brown, A. Calle, R. Dermer, B. Dieckleman, C. Fagundes, P. Fatemi, A. Gaydos, K. Gonzales, A. Hankins, T. Hirsch, W. Lee, A. Mastalerz , J. Medellin, D. Metzger, A. Morris, J. Pickett, K. Powers, J. Reed, J. Reynolds, N. Shipley, S. Spencer, J. Williams

Received January 21, 2015. The method was approved by the Expert Review Panel for Microbiology for Food and Environmental Surfaces as First Action. The Expert Review Panel for Microbiology for Food and Environmental Surfaces invites method users to provide feedback on the First Action methods. Feedback from method users will help verify that the methods are fit for purpose and are critical to gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author or methodfeedback@aoac.org. 1 Corresponding author’s e-mail: rpjechorek@mmm.com DOI: 10.5740/jaoacint.15-006 evaluated for each matrix. Samples evaluated by the 3M Petrifilm RYM Count Plate method were prepared in duplicate and incubated at both 25°C and 28°C. Plates at both temperatures were enumerated after 48 and 60 h of incubation. No significant difference was observed between the 3M Petrifilm RYM Count Plate method and the FDA BAM or ISO 21527 reference methods for each contamination level. No statistical differences were observed between samples analyzed by the 3M Petrifilm RYM Count Plate method (at either 25°C or 28°C) and the reference methods. No The 3M™ Petrifilm™ Rapid Yeast and Mold (RYM) Count Plate is a simple, ready-to-use chromogenic culture method for the rapid detection and enumeration of yeast and mold in food products. The 3M Petrifilm RYM Count Plate method was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 18, Yeasts, Molds and Mycotoxins and the ISO 21527:2008 Microbiology of Food and Animal Feeding Stuffs—Horizontal Method for the Enumeration for Yeast and Molds – Part 1: Colony Count Technique in Products with Water Activity Greater Than 0.95 and Part 2: Colony Count Technique in Products with Water Activity Less Than or Equal to 0.95 reference methods for raw almonds and raw frozen ground beef patties (77% lean). The 3M Petrifilm RYM Count Plate method was evaluated using a paired study design in a multi-laboratory collaborative study following the current AOAC Validation Guidelines. Three target contamination levels (low, 10–100 CFU/g; medium, 100–1000 CFU/g; high 1000–10000 CFU/g) as well as an uninoculated control level (0 CFU/g) were

statistical significant differences were observed between enumeration of colonies at 48 and 60 h on the 3M Petrifilm RYM Count Plate method and the reference methods. F oodborne yeasts and mold constitute a large and diverse group of microorganisms. Due to their heterotrophic nature, these microorganisms are able to adapt and survive in a wide range of environmental conditions including acidic and alkaline conditions, temperatures ranging from 5°C to 35°C and in low moisture (<0.85 Aw ) products (1, 2). Many of these species cause varying degrees of food decomposition leading to substantial economic loses (2). Several foodborne molds, and possibly some yeasts, may also be hazardous to human health due to their ability to produce toxic metabolites (1). The presence of these microorganisms in food commodities can indicate contamination of the product, inadequately cleaned food processing equipment, or inadequate food storage facilities (2). Cultural enumeration of yeasts and molds can take 5 to 7 days and the need for rapid enumeration is critical to the food industry. The 3M TM Petrifilm TM Rapid Yeast and Mold Count (RYM) Plate uses a cold-water-soluble gelling agent and an indicator system to facilitate the enumeration of yeast and molds after 48 h of incubation. The 3M Petrifilm RYM Count Plate allows for the simple and rapid enumeration of yeasts and molds in the food and beverage industries. Samples are diluted in 0.1% peptone water and a sample aliquot is plated onto the 3M Petrifilm RYM Count Plate. The sample aliquot is dispersed throughout the growth area and the plates can be incubated at 25–28°C. Enumeration of colonies occurs in as little as 48 h of incubation. If colonies appear faint, the plates can be incubated up to an additional 12 h for enhanced interpretation. The 3M Petrifilm RYM Count Plate provides gridlines to assist with the enumeration. Prior to the collaborative study, the 3M Petrifilm RYM Count Plate method was validated according to AOAC Validation Guidelines (3) in a harmonized AOAC Performance Tested Method SM (PTM) study. The objective of the PTM study was to demonstrate that the 3M Petrifilm RYM Count Plate accurately detected and enumerated yeasts and molds in selected foods as claimed by the manufacturer and that no difference in

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