Microbial Enumeration Test
USP 61 – Microbial Enumeration Test
USP 61 test provides quantitative enumeration of microbial content (bacteria, yeast or mold) in non – sterile products (pharmaceutical, cosmetic, and personal care products). USP 61 is also referred as microbial bioburden testing or microbial limits testing.
USP 61 test determines Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) present in the test sample.
Importance of USP 61 Test
- USP 61 test is established to determine whether a final product or formulation meets pre-specific criteria of microbiological safety. This product safety test is suggested by FDA for Pharmaceutical, Cosmetic, and Personal care products.
- Most Cosmetics and Personal care products are expected to be microbiologically contaminated. For safety concerns, all such ready to use products should be free of pathogenic microorganisms, especially eye care products, and have a very low count of non-pathogenic organisms.
- USP 61 test provides the microbiological examination of non-sterile products.
USP 61 – Microbial Enumeration Test Method
- Test samples are inoculated on Soybean-Casein Digest Agar for Total Aerobic Microbial Count (TAMC). And Sabouraud Dextrose Agar medium is inoculated for Total Yeast and Mold Count (TYMC).
- Antimicrobial agents present in test samples can impact the results of USP 61 test. To overcome this challenge, this test method also uses neutralization and dilution techniques using specific test organisms to ensure that antimicrobial agents of the product should not inhibit the growth of suspected microorganisms in samples.
- Test organisms used in USP 61 neutralization and dilution techniques include Pseudomonas aeruginosa (ATCC 15442), Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538P), Enterococcus hirae (ATCC 10541), Klebsiella pneumoniae (ATCC 4352), MRSA (ATCC 33591), Salmonella enterica (ATCC 10708), Candida Albicans (MTCC 3017).
- After a specified incubation period, microbial enumeration can be done using either plate count or membrane filtration test method.
Interpretation of Results for USP 61
- Total Aerobic Microbial Count (TAMC) is equal to the number of colony-forming units (CFU) on Soybean-Casein Digest Agar. If fungal colonies are found, they are counted as a part of TAMC.
- Total Yeast and Mold Count (TYMC) is equal to the number of CFU found on Sabouraud Dextrose Agar. If bacterial colonies are found, they are counted as a part of TYMC.
Microbe Investigations has incorporated fully equipped suites and analytical facilities for microbial enumeration tests.
Contact our experts now to discuss your test requirements for USP 61 and other related antimicrobial tests. We also perform USP 62 test to assess the growth of specific microorganisms in non sterile products.
Our experts understand the client’s needs and expectations first and take complete responsibility to provide reliable and accurate results.
USP 61 test, also known as Microbial Enumeration Test, determines the Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) in non – sterile product samples.
USP 61 test is applicable to Cosmetics and Personal care products.
The USP 61 test takes 5 to 6 days to complete.
We test for USP 61 using the following microbial strains: Pseudomonas aeruginosa (ATCC 15442), Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538P), Enterococcus hirae (ATCC 10541), Klebsiella pneumoniae (ATCC 4352), MRSA (ATCC 33591), Salmonella enterica ( ATCC 10708), Candida Albicans (MTCC 3017). Additional strains can be added on request.