Evaluation of the 3M Petrifilm™ Culture Plate Method for Enumerating Aerobic Flora and Coliforms in Poultry Processing Facilities

Abstract

Petrifilm™ methods were compared to traditional plating methods for monitoring microbial contamination in poultry processing facilities. No differences were seen between the Petrifilm methods and conventional method for enumeration of total bacterial populations, and no trends were seen in the ability of either method to detect coliforms in naturally contaminated samples. When processed poultry products were artificially inoculated with a variety of microorganisms, no difference in efficiency of recovery of the bacteria was noted. The Petrifilm methods were shown to be a practical and accurate alternative for monitoring microbial levels in poultry processing facilities. As the per capita consumption of poultry meat has increased in the U.S., poultry processors have a height-ened interest and concern about control of microbial contamination during processing operations. Petrifilm plates are dry medium films that provide a prepared culture method for microbiological examination of foods. There are two Petrifilm methods: Petrifilm SM (PSM) for enumeration of total aerobic flora, and Petrifilm VRB (PVRB) for enumeration of coliforms. PSM plates have been shown to be comparable to standard methods agar (SMA) pour plates for aerobic col-ony counts in raw milk (3) and fresh ground beef (8) and poultry carcasses of varying degrees of freshness (1). The method has also been shown to be effective for microbial monitoring of surfaces (5). PVRB plates have been shown to be comparable to violet red bile agar (VRBA) plates for raw milk samples (6). Both methods have been collaboratively studied (4) and are approved Official Final Action AOAC methods for use with raw and pasteurized milk.