Cosmetics Testing For Bacteria Contamination

Total Aerobic Bacteria

Cosmetics and personal care products should be free of microorganisms and safe for consumer use. The detection and elimination of microbial contamination of cosmetics and personal care products is vitally important to maximize shelf life, ensure product consistency and performance, and to meet federal and provincial regulations. This is achieved through use of a sound quality assurance and control program. Quality assurance program include testing of these products for microbial contamination. MBL analyses cosmetics and personal care products for microbial contamination. The following are the most common tests performed at MBL:

Aerobic Plate Count (APC)

Aerobic Plate Count determines the  total number of aerobic bacteria in a product. The test takes 48 to 72 hours.

Yeast and Mold Count

The Yeast and Mold Count test determines the total number of fungi (yeast and mold) in a product. The test takes about 5-7 days.

Antimicrobial Effectiveness Test (Challenge Test):

Antimicrobial preservatives are added in products to protect them from microbial growth. Antimicrobial efficacy test evaluates the effectiveness of antimicrobial preservatives. The test involves monitoring survival of known strains of microorganisms for 28 days. Samples are tested at different intervals to determine the survival of the organisms. The test demonstrates the efficacy of the product to stop the growth of organisms like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. The test requires at least 100-150 ml or grams of the product.

Minimum Inhibitory Concentration (MIC)

Minimum Inhibitory Concentration test determines the lowest concentration of the product inhibiting visible growth of microorganisms.

Zone of Inhibition

Zone of inhibition is the area of no bacterial growth around the product in the disk-diffusion test. A series of  test agent impregnated paper disks are placed on a plate inoculated to form a bacterial lawn. The plates are incubated to allow growth of the bacteria . If an organism is susceptible to an agent, a clear zone will appear around the disk where the growth has been inhibited. The size of this zone of inhibition depends on the sensitivity of the bacteria to the specific product and the product’s ability to diffuse through the agar.

MBL provides quality microbiological tests for cosmetic and other personal care products. If you have a question regarding a particular test (including those not listed here), please feel free to contact MBL.


Common Product Matrices

  • Liquids
  • Solids and powders
  • Creams and oil-based products
  • Aerosols
  • Anhydrous materials
  • Containers and packaging

Methods Of Testing

We use standard methods such as those of ASTM or methods recommended by US FDA or Health Canada.

Should you have a question concerning either our services or microbiological tests for cosmetics and personal care products, please call 905-290-9101.