2 2 Microbiological control

A guidance document on microbiological control of cosmetic products

2.1 Microbiological control of final product
2.2 Microbial contamination
- 2.2.1 During manufacturing
- 2.2.2 After opening
2.3 Preservation

The different needs for microbiological examinations of cosmetic products are established from the microbiological risk analysis, which are carried out in order to determine the type of cosmetic product (low microbiological risk etc) you have. The microbiological risk analyses include consideration of the type of user, site of application, potential alteration of cosmetic products as well as the pathogenicity of microorganisms.

Specified microorganisms are aerobic mesophilic bacteria or yeast undesirable in a cosmetic product and recognised as a skin pathogen species that may be harmful for human health or as an indication of hygienic failure in the manufacturing process. Microorganisms considered as specified microorganisms are Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Escherichia coli.

2.1 Microbiological control of final product

No limits for microbial contamination of cosmetics are enclosed in the Cosmetics Directive or in the national Danish implementation of this Directive. Recommendations on limits of microbial contamination in cosmetic products can be found in the notes of guidance for the testing of cosmetic ingredients and their safety evaluation prepared by EU´s Scientific Committee of Consumer Products (SCCP) (5). The Danish Environmental Protection Agency recommends the use of these levels.

In SCCP’s notes of guidance, two separate categories of cosmetics products are defined, as various skin areas can be differently sensitive.

Category 1	Products specifically intended for children under 3 years, eye areas and mucous membranes, leave-on products.
Category 2	Other products, rinse-off products.

The quantitative specifications are – Generally acceptable levels:

Category 1	Total viable count for aerobic mesophilic microorganisms ( bacteria, yeast and moulds) not more than 10²cfu/g or ml in 0,5g or 0.5 ml of the product
Category 2	Total viable count for aerobic mesophilic microorganisms not more than 10³cfu/g or ml in 0,1g or 0.1 ml of the product

It is not acceptable that the following potentially pathogenic microorganisms are present in cosmetic products:

Staphylococcus aureus
Pseudomonas aeruginosa
Candida albicans

The occurrence of indicator bacteria is not mentioned in SCCP’s notes of guidance (5). But it is generally acknowledged that neither the occurrence of E. coli nor other members of Enterobacteriaceae are acceptable in cosmetic products.

Qualitative limits:

Category 1	Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans or E.coli must not be detectable in 0.5g or 0.5 ml of the product.
Category 2	Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans or E.coli must not be detectable in 0.1g or 0.1ml of the product

2.2 Microbial contamination

Microbiological durability depends on product composition, content of preservatives, manufacturing hygiene, packaging, transport and storage. The ability of microorganisms to grow and reproduce in cosmetic products is well known. Water is essential for microbial growth and water-based products often have a limited durability, as they are sensitive to microbial growth. More are cosmetics ideal nutrient media for microorganisms.

2.2.1 During manufacturing

Contamination during production and filling in cosmetic products may occur.

Raw materials can contribute to a significant level of microbial contamination to the finished product. Testing of raw materials before use, especially those of natural origin is important. The specifications of the raw materials must include microbiological purity. Water is a raw material, and the most common ingredient. Water must be tested continuously for microbial growth. It might be necessary to sterilise deionised water to obtain a sufficient purity.

Many other conditions of production may influence the contamination during manufacturing, such as contaminated areas, insufficient manufacturing hygiene, personnel hygiene and insufficient preservation. Effective cleaning is very important.

2.2.2 After opening

From the moment of opening the cosmetic product is subject to constant and variable microbial contamination from the domestic environment and the consumer's hands and body (the skin). Since microorganisms are ever present in the home, especially in warm, moist areas, such as bathrooms and kitchens, cosmetics are exposed to contamination with both spoilage and potentially hazardous micro-organisms during use.

Purity after opening depends on the preservative ability of the product, suitability of the packaging, storage and application.

The following scenarios can contribute to contamination of a cosmetic product, fingers dipped in product, spillage of water into product, shampoo used by several different people

2.3 Preservation

The function of preservation is for consumer protection and prevention of spoilage during normal and reasonable product use. The preservatives inhibit the growth of contaminating microorganisms during manufacturing, storage and use by consumers after opening.

The preservative efficacy of a formulation cannot be predicted in every detail and must be confirmed by microbial challenge testing (see section 4.4) since the activity of the preservative is dependent on the effect of individual ingredients and the packaging in which it is stored. Preservatives must be used at the lowest concentration that ensures their efficacy and this must be determined during the product development process.

The efficacy of antimicrobial preservation in cosmetics can be tested with the Challenge test.

The use of preservatives in cosmetics cannot replace good manufacturing practice.