The 3M Petrifilm Aerobic Count Plates are a ready-to-use culture medium system for the enumeration of aerobic bacteria in food and environmental samples. The plates contain Standard Methods nutrients, a cold-water-soluble gelling agent, an indicator of microbial growth, and an overlaying plastic film. To use, simply inoculate the plate with a sample, incubate, and count colonies. The plates provide an easy, efficient alternative to conventional pour plate methods. They help save time and materials while providing consistent, reliable results. The plates are available in a variety of formats for enumeration of different microorganisms.