A preservation system is broader than a single preservative. It may include one or more preservatives together with antimicrobial boosters, chelating agents, appropriate pH, low water activity, suitable packaging and good manufacturing practices.

The objective is to prevent microorganisms from multiplying to unacceptable levels during manufacturing, storage and normal consumer use.

Formulation Dependence

Preservative performance is strongly influenced by the formulation.

pH, water activity, surfactants, polymers, oils and packaging can all change the availability and effectiveness of an antimicrobial ingredient.

A preservative that performs well in one formulation may perform poorly in another.

Testing

The preservation system should be evaluated in the finished formulation. Microbial challenge testing can be used to demonstrate whether the system provides adequate protection under defined conditions.

Preservation testing does not replace GMP or routine microbiological quality control.

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.

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