ISO 21148:2017

Overview

ISO 21148:2017 - "Cosmetics - Microbiology - General instructions for microbiological examination" provides harmonized, practical guidance for performing microbiological testing of cosmetic products. The standard sets out general instructions intended to ensure product quality and consumer safety by guiding laboratories on how to carry out microbiological examinations in line with an appropriate risk analysis (for example, products with low water activity, hydro‑alcoholic formulations or extreme pH). It is a general framework and notes that some details may not apply to every product type (e.g., certain water‑immiscible products).

Key topics and technical requirements

ISO 21148:2017 covers the full laboratory workflow and essential requirements, including:

• Premises and environmental control - layout of test areas, location, equipping and maintenance to prevent cross‑contamination.
• Equipment - requirements for microbiological cabinets, incubators, autoclaves, homogenizers, pH meters, balances, colony counters and cold storage.
• Strains and reagents - handling of reference strains and requirements for culture media preparation, sterilization (moist heat, dry heat, filtration) and storage.
• Personnel and hygiene - competence, training and hygienic precautions to protect staff and sample integrity.
• Apparatus and consumables - preparation, sterilization, management of sterile/clean glassware and treatment of contaminated material.
• Sampling and sample handling - sampling practices, transport, receipt, storage, conservation and destruction of cosmetic samples.
• Testing methods - preparation of initial suspensions and dilutions (water‑miscible vs. water‑immiscible products), counting and detection methods, expression of results and neutralization of antimicrobial product properties.
• Supporting procedures - annexes provide basic identification, plating/counting techniques and inoculum preparation guidance.

These elements together promote consistent, reproducible microbiological testing and laboratory safety.

Applications and who uses it

ISO 21148:2017 is relevant for:

• Cosmetic manufacturers and quality control laboratories performing cosmetic product testing and microbial contamination control.
• Contract testing and third‑party analytical laboratories that conduct routine microbial quality control and challenge tests.
• Regulatory bodies and auditors assessing laboratory practices for cosmetics microbiology.
• R&D teams developing product formulations that require microbial risk assessment.

Use this standard to establish or verify laboratory procedures, train personnel, support risk‑based test selection and document good microbiological practice.

Related standards

Refer to other ISO standards and technical guidance from ISO/TC 217 (Cosmetics) and relevant microbiology standards for complementary requirements and method specifics.