Standard Methods Agar conforms to APHA (American Public Health Association) and AOAC (Association of Official Analytical Chemists) specifications for the enumeration of bacteria in dairy, food, and other sanitary materials. This formulation is also synonymous with Plate Count Agar and Tryptone Glucose Yeast Agar, also used in standard methods. Enzymatic Digest of Casein and Yeast Extract supply nitrogenous sources, carbohydrates, vitamins, and minerals, while Dextrose is the main fermentable carbohydrate. Agar is the gelifying agent.