Dry rehydratable film method for rapid enumeration of coliforms in foods (3M Petrifilm Rapid Coliform Count plate): collaborative study.
A rehydratable dry-film plating method for coliforms in foods, the 3M Petrifilm Rapid Coliform Count plate method, was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual method for nondairy foods and the American Public Health Association's Standard Methods for the Examination of Dairy Products (SMEDP) method for dairy foods. Six food types, vanilla ice cream, cheddar cheese, fresh refrigerated uncooked pasta, wheat flour, prepared frozen macaroni and cheese, and frozen hash browns, were analyzed for coliforms by 11 collaborating laboratories. For each food product tested, the collaborators received 8 blind samples consisting of a control sample and 3 levels of inoculated sample, each in duplicate. The mean log counts for the methods were comparable. The repeatability and reproducibility variances of the Petrifilm Rapid Coliform Count method at 14 and 24 h were not significantly different from those of the standard methods.
Kinneberg
Karen M
KM
rtech laboratories, Arden Hills, MN 55164, USA. kkinn@landolakes.com
Lindberg
Kathryn G
KG
D002611:Cheese / Q000382:microbiology; D015169:Colony Count, Microbial / Q000379:methods*; D003470:Culture Media; D003611:Dairy Products / Q000382:microbiology; D004755:Enterobacteriaceae; D005433:Flour / Q000382:microbiology; D005516:Food Microbiology; D007054:Ice Cream / Q000382:microbiology; D008567:Membranes, Artificial; D012015:Reference Standards; D015203:Reproducibility of Results; D011198:Solanum tuberosum / Q000382:microbiology
D003470:Culture Media; D008567:Membranes, Artificial