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USP 61

Chapter 61 in the United States Pharmacopeia (USP/NF), entitled Microbiological Examination of Nonsterile Products: Microbial Enumeration Tests, contains methodology to test for Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC). These tests can be performed on finished products, raw materials, excipients and environmental swabs.

The TAMC test involves plating diluted samples with general nutrient agar, followed by 3-5 days of incubation, to recover colonies of organisms that can grow aerobically at mesophilic temperatures (30-35°C). Bacterial colonies, as well as fungal colonies that are recovered from this test are used in a final calculated plate count. Results are usually reported in colony forming units per gram (CFU/g).

The TYMC test involves plating diluted samples with fungal recovery media, followed by 5-7 days of incubation, to target fungal colonies (yeasts and molds) that can grow aerobically at ambient temperatures (20-25°C). Fungal colonies as well as bacterial colonies that grow on the plates are used in a final calculated plate count. Results are usually reported in colony forming units per gram (CFU/g).

When submitting new product formulations to Q Laboratories, a neutralization verification (suitability) will need to be performed.