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USP <61>

Microbial Enumeration Test

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USP 61 – Microbial Enumeration Test

The USP 61 test provides a quantitative enumeration of microbial content, including bacteria, yeast, and mold, in non-sterile products such as pharmaceuticals, cosmetics, and personal care products. USP 61 is also referred to as ‘Microbial Bioburden Test’ or ‘Microbial Limits Test’.

USP 61 test determines the 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.
  • Cosmetics and Personal care products are expected to be microbiologically safe. 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

USP 61 – Microbial Enumeration Test method

 

  • Test samples are inoculated on Soybean-Casein Digest Agar for the Total Aerobic Microbial Count (TAMC) and on Sabouraud Dextrose Agar for the Total Yeast and Mold Count (TYMC). 
  • Antimicrobial agents present in test samples can impact the results of the USP 61 test. To overcome this challenge, this test method also uses neutralization and dilution techniques 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 Test

  1. 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 on the Soybean-Casein Digest Agar, they are included in the TAMC.
  2. 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.

Benefits of USP <61> Testing

Ensures microbiological quality

The test provides a scientific approach to assess the microbiological safety of non-sterile commodities. Evaluating the Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) helps ensure that products are safe from microbiological contamination and meet the necessary microbiological safety standards.

Regulatory compliance

This test enables manufacturers to meet health standards provided by regulatory bodies like the FDA and EMA. Adherence to these standards is mandatory to get approval for the sale of pharmaceuticals, cosmetics, and other non-sterile products.

Detection of contaminants and Product Safety

The test identifies and quantifies possible microbial contaminants within the products. This is important for avoiding the release of the products that could be damaging to the health of people who consume the products. This is very crucial in products that are used externally on the skin, ingested, or used in hospitals.

Quality control and Risk mitigation

The test is used as an indicator of quality assurance to help manufacturers to ensure that the microbial quality of their products is checked and regulated at every stage of its processing. This assists in recognizing problem areas in advance and rectifying them if necessary. It can help avoid recalls which are expensive and detrimental to the firm’s brand image.

Prevention of spoilage

Microbial contamination can cause deterioration of the product and reduce its shelf life. This testing assists in identifying the microbial contaminants that may lead to spoilage thus allowing manufacturers to take appropriate preventive measures.

Broad applicability

The test is applicable to nonsterile products such as pharmaceuticals, cosmetics, and raw materials. This broad applicability makes it a flexible method that can be used effectively for assessing the microbiological quality of a wide range of products.

Consumer confidence

Products that comply with this standard are likely to inspire greater confidence among consumers regarding their safety and quality. This can enhance the brand’s reputation and trustworthiness in the market.

Applications of USP Chapter 61 Test

Pharmaceuticals

  • Ensuring the microbiological quality of non-sterile pharmaceutical products, including tablets, capsules, syrups, and topical medications.
  • Testing raw materials and excipients used in drug formulation to ensure they meet microbiological standards.

Cosmetics

  • Evaluating the microbial load in cosmetic products including creams, lotions, shampoos, and makeup.
  • Testing for microbial contamination in raw materials used in cosmetic formulations.

Personal care products

  • Assessing the microbiological quality of personal care products such as soaps, deodorants, and toothpaste.
  • Ensuring that products intended for personal hygiene do not contain harmful levels of microorganisms.

Food and Beverages

  • Testing non sterile food products and beverages for microbial contamination to ensure they are safe for consumption.
  • Monitoring the microbiological quality of ingredients and packaging materials used in the food industry.

Nutritional Supplements

  • Ensuring the microbiological safety of dietary supplements including vitamins, minerals, and herbal products.
  • Testing raw materials and finished products for microbial contamination.

Medical Devices

  • Evaluating the bioburden on non sterile medical devices and components prior to sterilization.
  • Ensuring that medical devices meet microbiological quality standards to prevent infections in patients.

Biopharmaceuticals

  • Testing biologically derived products such as vaccines, cell cultures, and tissue engineering products for microbial contamination.
  • Ensuring the microbiological quality of biopharmaceutical raw materials and intermediates.

Veterinary Products

  • Assessing the microbiological quality of nonsterile veterinary products including medications, supplements, and care products for animals.
  • Ensuring that veterinary products are free from harmful microbial contamination.

Water testing

  • Monitoring the microbiological quality of water used in pharmaceutical and cosmetic manufacturing processes.
  • Ensuring that water used in product formulations meets microbiological safety standards.

Household Products

  • Testing household cleaning products, detergents, and disinfectants for microbial contamination.
  • Ensuring that these products are safe for use in homes and do not harbor harmful microorganisms.

Packaging materials

  • Assessing the microbiological quality of packaging materials used for pharmaceuticals, cosmetics, and food products.
  • Ensuring that packaging materials do not introduce microbial contamination to the products they contain.

Research and development

  • Conducting microbiological testing during the development of new pharmaceutical and cosmetic products.
  • Evaluating the effectiveness of preservatives and antimicrobial agents in product formulations.

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 60 and 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. 

FAQs

This test, also known as the Microbial Enumeration Test, determines the Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) in non–sterile product samples.

The test is applicable to Cosmetics and Personal care products.

The test takes 5 to 6 days to complete.

We perform the test 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.

The acceptance criteria is TAMC of 100-1000 cfu/ml and TYMC of 10-100 cfu/ml.

The primary methods include Membrane Filtration, Plate-Count Methods (Pour-Plate and Surface-Spread Methods), and the Most-Probable-Number (MPN) Method.

It ensures that the products meet established specifications for microbiological quality, safeguarding consumer health by preventing contamination.

The enumeration test is a quantitative method used to determine the number of viable microorganisms present in a sample. This test is crucial for ensuring the microbiological quality of non-sterile products, including pharmaceuticals, cosmetics, personal care products, and medical devices.

The Total Aerobic Microbial Count (TAMC) is a microbiological test used to quantify the number of viable aerobic bacteria present in a sample. This test is an essential part of quality control for non-sterile pharmaceutical products, cosmetics, personal care products, and other items that must adhere to specific microbiological safety standards.

The Microbial Limit Test (MLT) is a set of procedures used to assess the microbiological quality of non-sterile pharmaceutical products, cosmetics, and personal care items. It determines whether a product meets predefined microbiological criteria to ensure safety and quality for consumers.

Microbial count, also known as microbial enumeration, is a method used to determine the number of microorganisms (such as bacteria, yeasts, and molds) present in a sample. This measurement is crucial in various industries, including pharmaceuticals, food and beverages, cosmetics, and water quality, to ensure product safety, quality, and compliance with regulatory standards.

A bioburden test is a procedure used to determine the number and types of viable microorganisms present on a product or surface before it undergoes sterilization. This test is essential in various industries, including pharmaceuticals, medical devices, and food production, to ensure that products are safe and meet regulatory standards for microbial contamination.

The duration of bioburden testing depends on the incubation periods required for different microorganisms. Typically, the incubation period for bacterial bioburden testing is 3 to 5 days at 30 to 35°C. For fungal bioburden testing, the incubation period is 10 to 14 days at 20 to 25°C. These periods allow sufficient time for the microorganisms to grow and be counted accurately.

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