ISO 11930:2019

Overview

ISO 11930:2019 - Cosmetics - Microbiology - Evaluation of the antimicrobial protection of a cosmetic product - is an international reference method for assessing the preservation efficacy and overall antimicrobial protection of cosmetic products. The standard specifies how to interpret data from a preservation efficacy (challenge) test and from a microbiological risk assessment (per ISO 29621) to determine whether a finished cosmetic product provides adequate protection against microbial contamination during intended use.

Key scope points:

• Applies primarily to water‑soluble or water‑miscible products (and can be adapted for water‑in‑oil internal phases).
• Defines a reference preservation efficacy test (challenge test) and interpretation rules.
• Excludes products classified as microbiologically low risk under ISO 29621 and Annex A.
• Can be used as a guideline during product development with justified modifications.

Key Topics

• Preservation efficacy (challenge) test: Inoculation of the formulation with calibrated microbial strains, monitoring survival over a 28‑day period, and calculation of log reduction values compared to acceptance criteria (criteria A or B in Annex B).
• Microbial strains and inocula: Use of relevant bacteria and fungi (e.g., bacterial strains, Candida albicans, Aspergillus brasiliensis are referenced) and controlled preparation/enumeration of inocula.
• Neutralizer efficacy: Mandatory demonstration that neutralizers used to stop preservative activity do not interfere with recovery of test organisms.
• Materials and methods: Requirements for diluents, neutralizers, culture media, lab equipment and procedures to limit variability when used as the reference method.
• Data interpretation: Combining preservation test results with microbiological risk assessment, package, production and usage factors to reach an overall evaluation.
• Reporting: Test report content and decision flow (see Annex A decision diagram).

Applications

Who uses ISO 11930:2019:

• Cosmetic formulators and R&D teams validating preservative systems.
• Quality control and microbiology laboratories performing challenge tests.
• Regulatory affairs professionals documenting product safety and compliance.
• Manufacturers assessing production, packaging and labeling impacts on antimicrobial protection.

Practical uses:

• Verifying preservative efficacy for market products.
• Supporting microbiological risk assessments (ISO 29621) when products are not low risk.
• Informing packaging and manufacturing controls that contribute to overall antimicrobial protection.
• Guiding development tests (with justified modifications) to optimize formulation preservation.

Related standards

• ISO 29621 - Guidelines for risk assessment and identification of microbiologically low‑risk products
• ISO 21148 - General instructions for microbiological examination
• ISO 21149 - Enumeration and detection of aerobic mesophilic bacteria
• ISO 16212 - Enumeration of yeast and mould
• ISO 18415 - Detection of specified and non‑specified microorganisms
• ISO 22716 - Good Manufacturing Practices (cosmetics)

Keywords: ISO 11930:2019, preservation efficacy test, antimicrobial protection, cosmetics microbiology, challenge test, microbiological risk assessment, neutralizer efficacy, cosmetic formulation.