AOAC ERP for Microbiology Methods Grants Official First Action Status to E. coli/Coliform Method

The AOAC Expert Review Panel (ERP) for Microbiological Methods for Food and Environmental Surfaces, co-chaired by Michael Brodsky of Brodsky Consultants and Wendy McMahon of Mérieux NutriSciences, granted First Action status to 3M™ Petrifilm™ Rapid E. coli/Coliform Count Plate, a selective and differential sample-ready-culture medium designed for the rapid enumeration of Escherichia coli and coliform in a broad range of foods and beverages and environmental surfaces.

The 3M Petrifilm Rapid E. coli/Coliform Count Plate was compared to reference methods from the U.S. Food and Drug Administration’s Bacteriological Analytical Manual (BAM) and International Organization for Standardization (ISO) 4832:2006 for enumeration of E. coli and coliforms. A total of nine participants across eight laboratories throughout the United States, Canada, Mexico, and Switzerland participated in the study.

The method was shown to be applicable for the enumeration of E. coli and coliform from pasteurized whole milk, butter, nonfat dry milk, raw ground pork, raw lamb chop, raw ground chicken, chicken carcass rinsate, shell eggs, liquid egg whites, powdered egg whites, fresh raw bean sprouts, frozen cranberries, infant formula with probiotics, infant formula without probiotics, infant rice cereal without probiotics, dry dog kibble, dry cat food, all-purpose flour, chocolate chip cookie dough, raw ground beef (73% lean), raw frozen chicken wings, raw milk, whole liquid egg, tuna sushi, smoked salmon, bunched raw spinach, pasteurized carrot juice, ready-made sandwiches (bread, deli meat and cheese), raw vegetable salad with mayonnaise-based dressing, chicken feed, soybean meal, stainless steel environmental sponges, and sealed concrete environmental sponges.

The ERP agreed that the method is well written, comprehensive, and easy to follow. Study results are well documented. The method is rapid, specific, and sensitive.

The method was adopted as First Action Official MethodSM 2018.13 and is available on eOMA at

AOAC invites method users to provide feedback on the use and performance of First Action Official MethodsSM. This information is critical in determining whether these methods should advance to Final Action status after the 2-year period from adoption. Comments can be sent to

For more information, contact Deborah McKenzie, senior director, Standards and Official MethodsSM, at

Full coverage appears in the January/February 2019 issue of Inside Laboratory Management.