Plate Count Agar originally formulated by Buchbinder et al (1) which is recommended by APHA (2,3,4) FDA (5) and ISO committee (6). Present formulation is recommended by BIS (7) for enumeration of microorganisms in food, water and wastewater. Casein enzymic hydrolysate provides amino acids and other complex nitrogenous substances. Yeast extract supplies Vitamin B complex. BIS recommends pour plate technique. The samples are diluted and appropriate dilutions are placed in petri plates. Sterile molten agar is added to these plates and plates are rotated gently to ensure uniform mixing of the sample with agar. Plate Count Agar is also suitable for finding out bacterial count from sterile rooms.
Storage and Shelf-life:
Store below 30°C in tightly closed container and prepared medium at 2 - 8°C. Use before expiry date on the label.
References:
1. Buchbinder, Baris and Goldstein, 1951, Publ. Hlth. Rep., 66:327.
2. Marshall R. (Ed.), 1992, Standard Methods for the Examination of Dairy Products 16th ed., APHA, Washington, D.C.
3. Vanderzant C. and Splittstoesser D. (Eds.), 1992, Compendium of Methods for the Microbiological Examination of Foods, 3rd ed., APHA, Washington, D.C.
4. Greenberg A. E., Clesceri L. S. and Eaton A. D. (Eds.), 1992, Standard Methods for the Examination of Water and Waste Water, 18th ed., APHA, Washington, D.C.
5. U.S. Food and Drug Administration, 1995, Bacteriological Analytical Manual, 8th ed., AOAC, Arlington, Va.
6. International Organization for Standardization (ISO), 1991, Draft ISO/DIS 4833.
7. Bureau of Indian Standards, IS : 5402 - 1969 (First Reprint 1983).