ISO 18415:2017

Overview - What ISO 18415:2017 covers

ISO 18415:2017, "Cosmetics - Microbiology - Detection of specified and non-specified microorganisms," provides general guidelines for detecting and identifying microbiological contamination in cosmetic products. The standard focuses on both specified microorganisms (commonly including Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Candida albicans) and other aerobic mesophilic non-specified microorganisms that may indicate hygienic failure or product spoilage. It describes a culture-based approach using an enrichment broth followed by isolation on non-selective agar media, plus identification workflows and suitability testing.

Key technical topics and requirements

• Microbiological risk analysis: Advises performing a risk assessment to determine applicability based on product type and intended use (e.g., site of application, vulnerable users).
• Scope of organisms: Defines specified vs non-specified organisms; national regulations may alter which organisms are considered specified.
• Sample preparation and dilution: Guidance for preparing initial suspensions for water-miscible, water-immiscible, and filterable products.
• Culture methods: Detection by enrichment broth and isolation on non-selective agar; other methods (including automated) can be used if their equivalence or suitability is demonstrated.
• Identification procedures: Practical tests outlined include Gram staining, oxidase and catalase tests, plus organism-specific identification steps for P. aeruginosa, E. coli, S. aureus and C. albicans. Annex A provides a general identification scheme.
• Neutralization and suitability tests: Procedures for demonstrating neutralization of antimicrobial properties (preservatives) and suitability of the enrichment method for the product matrix.
• Result reporting: Instructions on expression of detection results and interpretation (presence/absence, non-specified counts).

Practical applications - who uses ISO 18415

• Cosmetic quality control (QC) laboratories performing routine microbial surveillance.
• Manufacturers establishing in-house microbiological testing programs and raw material checks.
• Contract testing laboratories and third-party microbiologists validating methods for cosmetic matrices.
• Regulatory bodies and auditors assessing compliance with microbiological safety expectations.
• Useful for testing products across formulations, with caution for certain water-immiscible products where alternative methods may be required.

Related standards

• ISO 29621 (microbiological risk - low-risk products)
• ISO 21148 (general instructions for microbiological examination)
• ISO 18416, ISO 21150, ISO 22717, ISO 22718 (other cosmetic microbiology methods and considerations)

Keywords: ISO 18415, cosmetics microbiology, detection of microorganisms, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, enrichment broth, microbiological risk analysis, cosmetic product testing.