ISO 17516:2026

ISO 17516 is an ISO standard for cosmetics microbiology. It specifies acceptable quantitative and qualitative microbiological limits for finished cosmetic products and helps manufacturers, laboratories, and other interested parties assess microbiological quality and safety. The standard also supports decisions on when products judged microbiologically low risk may not need routine microbiological testing.

What does ISO 17516 specify?

ISO 17516 applies to all cosmetics and focuses on finished products. It sets the microbiological limits used to judge whether a cosmetic product is acceptable, and it points users to standard test methods and a result-interpretation flowchart.

The document is organized into clauses on scope, terms and definitions, principle, and microbiological limits, plus a normative Annex A for interpreting test results and a bibliography of related methods and guidance.

What are the key requirements of ISO 17516?

ISO 17516 sets the main microbiological acceptance criteria for finished cosmetics. In practice, it gives a common basis for release testing, supplier control, and investigating borderline results.

Product safety and product category

ISO 17516 starts from the idea that cosmetics and their raw materials are not expected to be sterile, but microorganisms must not affect consumer safety or product quality during intended or foreseeable use. That means the focus is not sterility - it is control of contamination at a level compatible with the product and its use.

The standard distinguishes products intended for children under three years of age, the eye area, or mucous membranes from other products. That matters because these products are treated more cautiously when you decide which limit applies.

Quantitative microbiological limit

ISO 17516 sets a limit for aerobic mesophilic microorganisms in finished products. The document also notes the inherent variability of plate count methods, so results close to the limit need careful interpretation. In practice, laboratories should not treat a single borderline count as a simple yes-or-no result without considering method variability.

The standard also points readers to USP Chapter 61 and EP Chapter 2.6.12 for interpreting results. This is useful when a count is near the acceptance limit and you need a defensible decision.

Qualitative limits for specified microorganisms

ISO 17516 expects finished cosmetics to be free from Escherichia coli, Pseudomonas paraeruginosa also known as Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans in 1 g or 1 ml of product. In practice, these are the organisms that trigger a clear fail when they are detected in the tested amount.

Non-specified microorganisms and risk-based assessment

ISO 17516 says that non-specified microorganisms are not automatically objectionable if they cannot grow in the product. That makes preservative performance and product formulation important, because a product that supports growth presents a higher microbiological risk.

The standard points to risk assessment, preservative efficacy studies such as ISO 11930, and the demonstration that the product cannot support microbial growth, including the approach in ISO 29621. This lets manufacturers justify why a particular product is controlled without relying only on routine counts.

Test methods and result interpretation

ISO 17516 refers users to standard microbiological methods when testing is needed, including methods for enumeration and detection of the relevant organisms. Annex A provides a flowchart to interpret test results against the limits in the standard. That helps laboratories and quality teams apply the same decision logic consistently.

What terms does ISO 17516 define?

• Product - the portion of an identified cosmetic product received in the laboratory for testing.
• Aerobic mesophilic microorganisms - mesophilic bacteria, yeast, and mould that grow aerobically under the specified test conditions.
• Specified microorganism - an organism considered undesirable in a cosmetic because it can indicate hygienic failure or create skin or eye infection risk.
• Escherichia coli - a gram-negative rod used as a specified organism in cosmetic microbiology control.
• Pseudomonas paraeruginosa - also known as Pseudomonas aeruginosa, a specified organism associated with contamination concerns.
• Staphylococcus aureus - a gram-positive coccus used as a specified organism in cosmetics testing.
• Candida albicans - a yeast used as a specified organism in cosmetics testing.

Who uses ISO 17516?

ISO 17516 is used by cosmetic manufacturers, contract laboratories, quality assurance teams, and microbiology specialists. It is relevant to product development, routine quality control, incoming raw-material checks, supplier qualification, and release decisions for finished cosmetics.

It is also useful for technical and regulatory staff who need to justify microbiological acceptance criteria for products with different risk profiles, especially products for young children, the eye area, or mucous membranes.

What changed in ISO 17516 from the previous edition?

ISO 17516 is the second edition and it replaces ISO 17516:2014. The changes stated for this edition are the addition of Clause 2, with subsequent clauses renumbered, and an updated bibliography.

Which standards are used with ISO 17516?

ISO 17516 is used together with several related standards and methods that support risk assessment, GMP, testing, and interpretation:

• ISO 29621 - identifies microbiologically low-risk products and supports decisions on whether routine testing is needed.
• ISO 22716 - gives Good Manufacturing Practices (GMP) for cosmetics.
• ISO 21148 - gives general instructions for microbiological examination.
• ISO 21149 - covers enumeration and detection of aerobic mesophilic bacteria.
• ISO 16212 - covers enumeration of yeast and mould.
• ISO 18415 - covers detection of specified and non-specified microorganisms.
• ISO 18416 - covers detection of Candida albicans.
• ISO 21150 - covers detection of Escherichia coli.
• ISO 22717 - covers detection of Pseudomonas aeruginosa.
• ISO 22718 - covers detection of Staphylococcus aureus.
• ISO 11930 - evaluates the antimicrobial protection of a cosmetic product.

What does the ISO 17516 document contain?

ISO 17516 contains the acceptance limits in Table 1, the technical definitions needed to apply those limits, and the principle behind the microbiological control approach. It also includes a normative Annex A with a flowchart for interpreting test results.

The bibliography points to the related test methods and supporting guidance used for enumeration, detection, preservative evaluation, and low-risk product assessment. That makes the standard useful both as a decision document and as a starting point for choosing the right laboratory method.