The chemicals contained in the formulations of cosmetic products create favorable conditions for the growth of microorganisms in them. For this reason, the microbial quality of cosmetic products is influenced by both raw materials and water content and environmental factors. Until recently, though, cosmetic products did not have to be sterile. With the use of cosmetic products, a number of damages and discomforts have arisen in the human body due to the microbiological influences within them. Therefore, new production conditions and methods have been introduced for cosmetic manufacturers.

The microbiological effects of cosmetic products were first encountered in New Zealand in 1946. Four babies died of talcum powder. In 1963, Salmonella infections were found in people using thyroid powder tablets. An eye drop containing Pseudomonas aeruginosa in its formula has caused widespread eye infections. Subsequent infections have occurred in people using cosmetic products contaminated with Pseudomonas aeruginosa.

As such, the risks posed by cosmetic products have attracted the attention of employees in this field and studies have been initiated immediately. Companies producing cosmetic products have to make sure that the products are safe and quality and do not contain any harmful microorganisms. For this reason, before the products are offered to the consumer, they have to undergo various tests in production and development stages in order to ensure product safety. The most common of these tests are:

• Total aerobic mesophyll bacteria count
• Anaerobic bacteria count
• Staphylococcus sp. count
• Searching for Staphylococcus aureus
• Escherichia coli count / search
• Salmonella sp. Searching
• Total mold-yeast count
• Pseudomonas sp. count
• Searching for Pseudomonas aeruginosa
• Candida albicans counting / searching

According to the standards and criteria published both by the Turkish Standards Institute and by foreign organizations, the following substances should not be present in cosmetic products:

• Escherichia coli Pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhimurium
• Pathogen yeast named Candida albicans
• Aspergillus niger mold

Methods for detecting microbiological contamination in cosmetic products have traditionally been applied to their culture. However, depending on the development of technology, the use of new molecular methods gives rapid results in the identification of microorganisms. In traditional methods, it is difficult and long time to isolate, count and determine the specificities of microorganisms one by one. Therefore, rapid methods have been developed since 1990 years. These methods are also used in cosmetic products to detect bacteria and yeasts very quickly and precisely.

In the accredited laboratories, the above-mentioned four pathogenic bacteria and one pathogenic yeast are identified by both classical and molecular biological methods and bacteria and yeast formation are determined in cosmetic products and the effects of the packaging on the products are determined.

The quality of cosmetic products and the fact that they do not cause problems in terms of consumer health depend on different parameters. For example, harmful chemicals such as mercury in cosmetic products can cause skin irritation and allergies. Cosmetic products should not be contaminated with a microorganism that would cause such infections.

For example, glycerin in cosmetic products can be metabolised by pathogenic bacteria if it finds appropriate acidity and moisture conditions. In particular, aqueous cosmetics create an ideal environment for the formation of fungi and bacteria in terms of moisture. Cosmetic products such as lipsticks, eye shadows, toothpastes, shaving creams, soaps and shampoos are very easy to reproduce microorganisms. Microorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhimurium or pathogenic bacteria are very common in these products.

There are many sources of contamination in cosmetic products. Examples include the lack of purity of water used in production, the contamination of the raw material used, the non-sterile equipment used during production, and the contamination by air.