As described in USP <2021>, this microbial enumeration test provides a quantitative evaluation of the microbial content of nutritional supplements, also known as microbial bioburden testing or microbial limits testing. USP <2022> is the method used to determine the presence or absence of objectionable organisms or pathogens within a nutritional or dietary sample. Both tests are primarily designed to determine whether a sample complies with an established specification for microbiological quality.
USP <2021>: Microbial Enumeration Tests
The USP <2021> test provides for the estimation of the number of viable aerobic microorganisms present in nutritional supplements of all kinds, from raw material components to final, finished products. This test provides for the estimation of the number of viable aerobic microorganisms present within a sample. The sample is typically diluted, plated, and then incubated. Microbial enumeration of the sample can be achieved by membrane filtration, plate, or multiple tube methods. This chapter provides procedures for the following tests:
- Total Aerobic Microbial Count (TAMC)
- Total Yeast and Mold Count (TYMC)
- Enterobacterial Count (Bile-Tolerant Gram-Negative Bacteria)
USP <2022>: Absence of Specified Microorganims
The USP <2022> test is performed to determine the presence or absence of a specified list of microorganisms within nutritional and dietary supplements: Clostridium species, Escherichia coli, Salmonella species, and/or Staphylococcus aureus. As compared to USP <2021>, the sample is first enriched and then streaked onto the appropriate selective agar based upon the organism (s) above.
The USP <2021> and/or <2022> preparatory test is used to establish the method, which in the presence of the product, allows the detection of the microorganism (s).