EN ISO 21149:2017 PDF

Overview

EN ISO 21149:2017 / ISO 21149:2017 - "Cosmetics - Microbiology - Enumeration and detection of aerobic mesophilic bacteria" - provides harmonized, practical guidelines for the microbiological examination of cosmetic products. The standard covers methods to enumerate aerobic mesophilic bacteria by plate counting or membrane filtration, and to detect their absence by enrichment. It is a CEN-endorsed European implementation of the ISO document and supersedes the 2009 edition.

Key topics and requirements

• Scope and principle
  • General guidance for counting and detecting aerobic mesophilic bacteria in a wide range of cosmetics.
  • Allows substitution of alternative (e.g., automated) methods provided equivalence or suitability is demonstrated.
• Counting methods
  • Plate count (pour-plate, spread-plate) and membrane filtration procedures for colony enumeration after aerobic incubation.
• Detection by enrichment
  • Procedures to confirm absence/presence of bacteria after selective enrichment and incubation.
• Diluents, neutralizers and culture media
  • Selection and use of appropriate diluents and neutralizers to counteract antimicrobial properties of products.
• Sample handling and apparatus
  • Recommendations for sample preparation, handling of water-miscible vs. water-immiscible products, and laboratory equipment.
• Suitability tests
  • Requirements for demonstrating that chosen methods neutralize antimicrobial activity and accurately recover microorganisms (suitability testing instead of “validation” wording).
• Results and reporting
  • Calculation, expression and interpretation of colony counts and detection outcomes; guidance for test reports.
• Annexes and bibliography
  • Informative annexes listing additional diluents, media and neutralizers; bibliography includes related guidance such as ISO 29621 for low-risk products.

Applications and who uses it

• Cosmetic manufacturers - routine quality control, batch release, stability and shelf-life testing.
• Contract and third‑party microbiology laboratories - standardized test methods for customer reporting and regulatory compliance.
• Regulatory bodies and auditors - assessment of microbiological safety procedures and lab practices.
• R&D and formulation teams - assessing preservative systems, compatibility with test methods, and mitigation of contamination risk.
• Supplier and raw-material testing - incoming quality control for ingredients and water.

Practical use includes investigating contamination events, demonstrating product safety for consumers, and ensuring comparability across labs and markets.

Related standards

• ISO 29621 - Guidance on microbiological risk assessment and low‑risk cosmetic products.
• ISO/TC 217 and CEN/TC 392 are the technical committees responsible for cosmetics microbiology standards.

Keywords: EN ISO 21149:2017, ISO 21149:2017, cosmetics microbiology, aerobic mesophilic bacteria, enumeration and detection, plate count, membrane filtration, enrichment, neutralizers, suitability test, microbiological risk analysis.