Preservation System – Cosmetic Uses in Product Protection

What Is a Preservation System?

A preservation system is the combination of ingredients and formulation conditions used to control the growth of microorganisms in a cosmetic product. It is particularly important for products containing water, which can provide a suitable environment for bacteria, yeasts and moulds.

A preservation system may consist of a single preservative or, more commonly, a combination of preservatives and supporting ingredients. Its effectiveness depends on the complete formulation rather than on the preservative alone.

Cosmetic Uses of Preservation Systems

Preservation systems are commonly required in water-containing products such as:

• Creams and lotions
• Serums
• Cleansers
• Shampoos and conditioners
• Shower gels
• Liquid soaps
• Toners and facial waters
• Water-based gels and masks

Anhydrous products generally present a lower microbiological risk because they contain little or no available water, although their overall microbiological safety still depends on the formulation, manufacturing process and packaging.

Factors Affecting Preservation

The effectiveness of a preservation system can be influenced by several formulation parameters, including:

• pH: Many preservatives have a specific pH range in which they are most effective.
• Water activity: The amount of water available to microorganisms can influence microbial growth.
• Ingredient interactions: Surfactants, emulsifiers, polymers, proteins and other raw materials can affect preservative availability.
• Packaging: Packaging design can influence the likelihood of microbial contamination during consumer use.
• Manufacturing hygiene: Good manufacturing practices are essential because preservatives should not be considered a substitute for hygienic production.
• Preservative concentration: The selected preservative system must be used at an appropriate and legally permitted concentration.

Preservation System Development

Selecting a preservation system requires consideration of the entire formulation. A preservative that performs well in one cosmetic product may not provide the same level of protection in another formulation.

Preservation efficacy is commonly evaluated through microbiological testing, including a challenge test, in which the finished product is deliberately exposed to specified microorganisms and monitored to determine whether the preservation system can control their growth.

The preservation system should therefore be evaluated in the final formulation rather than only in individual raw materials or laboratory screening tests.

References

ISO 17516. Cosmetics — Microbiology — Microbiological limits.

ISO/TR 19838. Microbiology — Cosmetics — Guidelines for the application of ISO standards on Cosmetic Microbiology.

European Commission. SCCS Notes of Guidance for the Testing of Cosmetic Ingredients and their Safety Evaluation.