The number of people using cosmetics continues to grow, and
the quantities consumed keep increasing every year. As the production
increases, the industry is faced with great concern regarding the microbial contamination of
personal care and cosmetic products. The implications of microorganism
contamination include massive product waste and financial losses for the
manufacturer, not to mention consumer injury or infection. While there are very
few cases of the latter happening, the occurrence of such episodes can
drastically impact the reputation of a brand.
Cosmetic Microbiology
Various factors contribute to the provision of favorable conditions for microbial growth including the ingredients used, the unsterile production process, and the storage temperatures. Microorganisms in the raw materials or environment can get into the product during its manufacture. Microbial contamination can also occur during storage or use by the consumer, though manufacturers try to prevent this by adding chemical preservatives to their products.
Microbiology Quality Assurance of Cosmetics and Personal Care Products
The use of preservatives in cosmetics gives rise to two problems: easy contamination of the cosmetic caused by the use of minimal amounts of antimicrobial agents for economy and safety, and human injuries due to the use of large amounts of antimicrobial agents to prevent contamination. This implies that cosmetic industries have to strike a balance with the preservatives that they use in order to prevent microbial growth without irritating the consumer. Popular preservatives include methylisothiazolinone, formaldehyde releasers, formaldehyde, and parabens.
The effectiveness of the preservative used is verified through Preservative Efficacy Testing (PET). While this test is an essential part in the microbial quality assurance of cosmetics and personal care products, it cannot indicate with certainty that contamination of the product will not occur during storage or use. In such cases, contamination is often caused by microbes that are not tested in the PETs, or manufacturing errors such as miscalculation of the preservative added. To ensure that the products are not contaminated with microorganisms that will grow during storage, manufacturers are required to conduct total microbial test count tests such as the United State Pharmacopeia, USP <61>.
These tests provide a complete quantitative analysis of finished products in order to determine the Total Yeast and Mold Count (TYMC), as well as the Total Aerobic Microbial count (TAMC) that they contain. In the event that contamination is detected, the same methods are used to test raw materials in order to establish the origin of the contamination.
The full USP <61> test specifies 4 bacterial indicators of contamination in cosmetics including Escherichia coli, Staphylococcus aureus, Salmonella spp. and Pseudomonas aeruginosa. The test also contains neutralization and recovery validations that ensure the techniques used in the microbial detection tests are sufficient to provide accurate results. This is a crucial step since most of the preservatives used in cosmetic products have the ability to inhibit microbial growth on laboratory agar plates, resulting in false-negative results.
Pharmaceutical Microbiology
There is no acceptable standard for microbial limits in personal care products, though they are not meant to be completely free from microbes. Modern microbiological instruments allow cosmetic manufacturers to maintain a maximum of 100 Colony Forming Units (CFU) of fungi or bacteria per ml or gram of product, as recommended, while keeping their products free from hazardous microbes.
Contact Biolumix to learn more
about microbial testing of cosmetics.
Biolumix
3928 Varsity Dr.
Ann Arbor, MI 48108
Phone: (734) 984-3100
Fax: 734-222-1830
Email: info@mybiolumix.com
