ISO 20743:2021

Overview - ISO 20743:2021 (Textiles - Determination of antibacterial activity of textile products)

ISO 20743:2021 defines quantitative test methods for determining the antibacterial activity of textile products and nonwovens. The standard applies to all textile forms - cloth, wadding, thread and materials for clothing, bedclothes, home furnishings and miscellaneous goods - regardless of the type of antibacterial agent (organic, inorganic, natural or man-made) or application method (built-in, after‑treatment or grafting). It provides laboratory procedures and measurement options so manufacturers, testing laboratories and regulators can generate objective, comparable data on antibacterial performance.

Key topics and technical requirements

• Scope and applicability: Covers all antibacterial textile products and common product forms.
• Three inoculation methods:
  • Absorption method - inoculum applied directly onto specimens.
  • Transfer method - bacteria placed on agar and transferred onto specimens.
  • Printing method - bacteria applied via a filter and “printed” onto specimens.
    Users select the most suitable method based on intended use, environment and surface properties.
• Quantitative enumeration methods:
  • Colony plate count (plate count) method - CFU-based enumeration (Annex C).
  • Adenosine triphosphate (ATP) luminescence method - rapid ATP-based measurement (Annex D).
• Supporting content: Procedures for strain handling and storage (Clause 7, Annex A), safety precautions, required apparatus, reagents and media, and example test workflows (Annex E).
• Judgement and reporting: Guidelines for evaluating antibacterial efficacy and preparing test reports (Clauses 9–10).

Practical applications and who uses it

ISO 20743:2021 is used by:

• Textile manufacturers and finishers to validate and optimize antibacterial treatments during R&D and production.
• Independent testing laboratories for performance verification and certification testing.
• Quality assurance and procurement teams to compare product claims and ensure batch consistency.
• Regulatory bodies and spec writers looking for reproducible, standardized test evidence for market surveillance or procurement specifications.

Benefits include producing reproducible, comparable quantitative data for product development, marketing claims, regulatory compliance and quality control.

Related standards

• ISO 20645 - Qualitative method for antibacterial activity (historical/complimentary reference).
• ISO 6330 - Domestic washing and drying procedures referenced for sample conditioning and laundering effects.

Keywords: ISO 20743:2021, antibacterial activity, textiles, antibacterial test methods, absorption method, transfer method, printing method, colony plate count, ATP luminescence, textile testing.