ISO 11930 with suitability – Evaluation of the antimicrobial protection of a cosmetic product (standard timepoints include D7, D14 and D28)

This method evaluates the antimicrobial activity of a product to help ensure the safety to consumers. ISO 11930 is deemed the industry standard test method for evaluating the preservative effectiveness of cosmetics and personal care products.

The ISO 11930 preservative efficacy test method is based on the inoculation of a personal care product with a known concentration of 5 relevant strains of microorganisms; S. aureus, E. coli, P. aeruginosa, C. albicans, and A. brasiliensis. The plates are incubated for 28 days, and at each time point (days 7, 14 and 28), the plates are evaluated in order to measure the percent reduction. This is compared against the acceptance criteria required by the method for acceptable preservation.

ISO 11930 Acceptance Criteria

• Criteria A:
  • For bacteria, the product must demonstrate no less than a 3 log reduction from the initial count at 7 days, and no increase from the 7 day count at days 14 and 28.
  • C. albicans must be reduced by no less than 1 log at 7 days and show no increase from the 7 day count at days 14 and 28.
  • A. brasiliensis must show no increase from the initial count at 14 days and no less than a 1 log reduction at 28 days.
• Criteria B:
  • For bacteria, the product must demonstrate no less than a 3 log reduction from the initial count at 14 days and no increase from the 14 day count at day 28.
  • C. albicans must be reduced by no less than 1 log at day 14 and show no increase from the 14 day count at day 28.
  • A. brasiliensis must show no increase from the initial count at 14 and 28 days.