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ISO 21149:2017 – Standard Method for Detecting Aerobic Mesophilic Bacteria in Cosmetics
ISO 21149:2017 is one widely accepted standard that provides guidelines for testing cosmetic products for microbial contamination. Ensuring the microbiological safety of cosmetic products is a crucial step in protecting consumers from potential health risks. The international standard describes methods to enumerate and identify the presence of pathogenic aerobic mesophilic bacteria in cosmetics. This standardization of the protocol makes it an essential tool for manufacturers aiming to meet high product quality as well as microbiological safety standards.
While this standard is applicable to a wide range of cosmetic products, alternative methods may be required for testing certain water-immiscible formulations. The presence of aerobic mesophilic bacteria is determined through either direct colony counting on agar plates or through an enrichment process that monitors the growth of bacteria.
Compliance and industry standards for ISO 21149 testing
ISO 21149 is part of a series of microbiological standards used to determine the safety of cosmetic products. This standard is designed to work in conjunction with other standards such as ISO 21148, which provides general guidelines on microbiological analysis for cosmetics. Compliance is a necessity for cosmetic manufacturers to meet industry standards and other regulatory requirements. Manufacturers who adhere to this standard demonstrate their commitment to product and consumer safety alike.
Test organisms used in ISO 21149 testing
At Microbe Investigations Switzerland, the test is performed using the following bacterial strains: Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 15442). Additional strains can be added on customer request.
ISO 21149 test method for aerobic mesophilic bacteria detection
Sample preparation: 1g or 1 ml of cosmetic test sample is added to the enrichment broth to prepare the initial suspension.
Plate method for ISO 21149 testing
- Pour plates or spread plates are prepared by using a specified culture medium.
- The plates are inoculated with a known quantity of initial suspension.
- The inoculated plates are incubated aerobically at 32.5°C ± 2.5°C for 72 ± 6 hours.
- After the incubation period, the number of colony-forming units (CFU) is counted and the number of aerobic mesophilic bacteria per ml per gram of the cosmetic product is calculated.
Membrane filtration in ISO 21149 test procedure
- A defined amount of sample is filtered through a membrane filter and washed in a filtration apparatus containing a small amount of suitable sterile diluent.
- The membrane filter is then transferred onto an agar plate and incubated at 32.5°C ± 2.5°C for 72 ± 6 hours.
- After incubation, the number of colony-forming units (CFU) is counted and the number of aerobic mesophilic bacteria per milliliter or per gram of the cosmetic product is calculated.
Detection of aerobic mesophilic bacteria by enrichment broth
- A defined amount of the sample preparation is inoculated in a non-selective liquid medium containing appropriate neutralizers and/or dispersing agents.
- The sample mixture is then incubated at 32.5°C ± 2.5°C for at least 20 hours.
- After incubation, an aliquot of the previously inoculated liquid medium is transferred to a non-selective solid agar medium.
- The plates are subjected to aerobic incubation at 32.5°C ± 2.5°C for 48 to 72 hours.
- The plates are observed for any bacterial colonies and the results are expressed as the “presence or absence” of aerobic mesophilic bacteria per sample of the cosmetic product.
Importance of ISO 21149 testing in cosmetic safety
Cosmetic products are usually exposed to various environmental conditions during their production, handling and storage procedures that encourage the proliferation of bacteria. This compromises the safety and efficacy of such products. Testing according to this standard allows the early detection of potential microbial contaminations in cosmetics so that contaminated products do not reach the markets.
Products that fail the standards efficacy criteria often cause skin irritation or allergic reactions when used by consumers, especially those with sensitive skin. The early detection of these bacteria helps manufacturers reduce such risks from their end and thus safeguard both the product and the consumer.
Applications of ISO 21149 testing in the cosmetic industry
The ISO standard 21149 is widely used for testing cosmetics and personal care products. The scope of this standard extends to creams and lotions, hair sprays, eye care products, essential oils and more. The finished product or the raw materials used to prepare these products must be tested for microbiological safety to prevent consumers from harmful bacterial infections.
Benefits of ISO 21149 testing for cosmetics
- Ensures consumer safety by detecting harmful bacteria.
- Prevents product spoilage and potential health risks.
- Enhances brand reputation by demonstrating compliance to international standards.
- Helps avoid costly product recalls due to contamination.
- Demonstrates a commitment to international regulatory compliance.
Conclusion – Ensuring cosmetic safety with ISO 21149 testing
Maintaining the microbial safety of cosmetic products is a non-negotiable factor in today’s increasingly regulated industry. The ISO standard ensures the safety of products by providing a standard testing protocol for assessing the quality and safety of the products. Manufacturers can ensure that their products are free from microorganisms by consulting this test and eventually safeguard the well-being of their consumers. Additionally, they can also gain customer confidence by demonstrating compliance with the standard.
At Microbe Investigations Switzerland (MIS), we provide ISO 21149 testing services that help cosmetic manufacturers ensure their products meet the highest standards of microbiological safety.
Contact us today to learn more about our services and how we can assist in safeguarding your cosmetic products.
FAQs on ISO 21149 testing and aerobic mesophilic bacteria
ISO 21149 test outlines a method for enumerating and detecting mesophilic aerobic bacteria present in cosmetic products by counting colonies on a non-selective agar medium or by checking the “presence or absence” of bacterial growth after enrichment.
ISO 22149 test applies to cosmetic and beauty products with a higher potential risk of mesophilic aerobic bacterial contamination.
The ISO 21149 test takes 4 weeks to complete.
At Microbe Investigations, we test for ISO 21149 using the following bacterial strains: Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 15442). Additional strains can be added on customer request.
The standard outlines the methods for detecting and enumerating aerobic mesophilic bacteria in cosmetic products.
Microbial contamination is detected either by counting colonies on an agar plate after incubation or by using an enrichment broth method for detecting low levels of bacteria.
Regular testing throughout the product life cycle, including during the development, manufacturing and shelf-life phases, is generally recommended.
ISO 21149 tests for the presence of bacteria while ISO 16212 tests for the presence of yeast and mold.
Yes, the standard can be used to test raw materials too.
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