Cosmetic products cover a wide range of everyday consumer products and their main component is water, so they are a suitable medium for the growth of various microorganisms that can lead to spoilage, discoloration or odor of the product. The use of appropriate preservatives in cosmetic products is essential to ensure the health of the product until the end of the expiration date, prolong its shelf life, maintain the appearance of the product and effectiveness.
Choosing the right preservative for the product is very important and the parameters that should be considered when choosing can be mentioned as follows: activity in a wide range (bacteria, mold and yeast), low toxicity, wide pH range, temperature stability, non-interference with formulation materials and product container and finally price
Different products have different microbial risks depending on their nature such as water activity, pH, nutrients, etc. For example, bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus grow in wet emulsions and cause off-flavors and odors, or yeasts such as Candida albicans prefer products with a higher pH. Mold species such as Aspergillus niger can pose a risk in anhydrous powders.
Regulatory requirements and restrictions on the use of preservatives are closely followed by regulators.
The European Union has introduced a list of all substances that can be used as preservatives in cosmetic products, along with their maximum concentrations and other restrictions.
The FDA does not have a specific list of approved preservatives, but manufacturers are required to ensure that the products they market are safe.
Ensuring that the preservative system is resistant to microbial growth during the product’s shelf life is essential for the quality and safety of cosmetic products.
The minimum inhibitory concentration (MIC) test is one of the most important tests to determine the type of preservative and its concentration.