Written by Oliver Dsa, MSc, senior virologist at Airmid Healthgroup, where he leads testing and research on airborne pathogens, indoor air quality, and antiviral technologies in real-world environments.
Published: June 28, 2018
Introduction to Antibacterial Treated Surfaces and Textiles
Most microorganisms do not exist freely but rather attach to surfaces, where they can be transferred to other locations, such as human skin or food. If transferred to a favorable environment, these microbes may multiply and cause adverse effects in exposed individuals[1]. Antimicrobial treatments aim to prevent surfaces from becoming reservoirs of infection[2].
This growing concern has made antibacterial surfaces highly attractive to both consumers and manufacturers, leading to increased innovation and marketing in this area[3]. Antimicrobial agents have been applied to a variety of materials, including non-porous surfaces (e.g., plastics, metals) and porous surfaces (e.g., natural and synthetic textiles)[4].
Antimicrobial efficacy testing in progress—scientists evaluate treated surfaces and textiles under controlled laboratory conditions to verify antibacterial claims.
The Importance of Testing and Scientific Validation
It is critical that antibacterial treated surfaces and textiles undergo standardized testing to verify their antimicrobial efficacy. Scientific validation provides manufacturers with credible data to support product claims. Effective test methods must be reproducible and consider variables such as experimental conditions, proper controls, and the type and concentration of microorganisms used[2].
The type of microorganism used also determines the nature of the antimicrobial claim—whether antibacterial, antifungal, or antiviral.
Standard Methods to Test Antibacterial Efficacy
Several industry-recognized organizations have developed standardized testing protocols for evaluating antimicrobial performance. These include:
International Organization for Standardization (ISO)
American Society for Testing and Materials (ASTM)
American Association of Textile Chemists and Colorists (AATCC)
This article focuses on bacterial testing methods, although adaptations for antifungal and antiviral evaluations also exist.
Testing Non-Porous Antibacterial Surfaces
JIS Z 2801 and ISO 22196
The Japanese Industrial Standard JIS Z 2801 is widely used for testing antibacterial activity on non-porous surfaces such as plastic, metal, and ceramic[^5]. Developed through collaboration between research institutions and industry, this method inspired the international standard ISO 22196[7]. Both protocols involve applying a bacterial suspension (commonly Escherichia coli or Staphylococcus aureus) to the test surface under a coverslip. After 24 hours of incubation at 35°C, viable bacteria are quantified.
Strengths:
Quantitative
Triplicate testing
High reproducibility
Limitations:
Represents ideal rather than real-world conditions
Bacteria may adhere to the coverslip, affecting results
Some researchers omit the coverslip to improve accuracy[^4]
ASTM E2149 – Dynamic Shake Flask Method
The ASTM E2149-13a method evaluates antimicrobial efficacy under dynamic conditions[8]. In this test, the sample is immersed in a bacterial suspension (e.g., Klebsiella pneumoniae) and agitated to ensure consistent contact. The reduction in viable bacteria is measured post-exposure.
Advantages:
Suitable for irregularly shaped objects
Disadvantages:
Less representative of real-world use
Better suited for proof of concept than field relevance
Testing Antibacterial Activity in Porous Materials (Textiles)
AATCC 100 – Industry Standard for Textiles
The AATCC Test Method 100 is the most commonly used protocol for evaluating antibacterial textiles[9]. Bacteria are absorbed into textile swatches and incubated in high humidity. Survivors are extracted and counted.
Drawbacks:
Uses a full nutrient broth that may exaggerate bacterial growth
Typically not repeated
Ambiguous pass/fail criteria[10]
JIS L 1902 and ISO 20743
JIS L 1902 improves on AATCC 100 by conducting the test in triplicate and using a diluted broth with fewer nutrients[11]. It includes a qualitative agar plate method (inspired by AATCC 147[12]) that checks for bacterial inhibition zones around the test textile. The ISO 20743 standard combines elements of JIS L 1902 and AATCC 100[13].
These two methods are considered the most comprehensive for evaluating antibacterial textiles[10]
Conclusion: The Need for Comprehensive Antibacterial Testing
Various validated methods exist for assessing the antibacterial efficacy of treated surfaces and textiles. These standardized test methods serve as a vital first step to demonstrate that a product performs as intended against target microbes[14]. However, real-world testing is equally important.
For robust evaluation, additional testing that simulates actual use, such as exposure to wear, cleaning cycles, and long-term durability, should be considered. This can include modifying standard methods or conducting field studies to capture the long-term performance of antibacterial treatments.
Related Standards and Test Methods
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Keywords
antibacterial testing methods, ISO 22196, JIS Z 2801, AATCC 100, antimicrobial textiles, surface efficacy testing, antibacterial surfaces, antibacterial textiles, surface testing, microbiology, textile innovation, antimicrobial coatings, antibacterial standards
References
1 Verran, J. (2002) Biofouling in Food Processing: Biofilm or Biotransfer Potential? Food and Bioproducts Processing 80 (4), 292-298
2 OECD. (2007) Analysis and assessment of current protocols to develop harmonised test methods and relevant performance standards for efficacy testing of treated articles/treated materials. ENV/JM/MONO(2007)4 (PDF 283 KB)
3 Haldar, J. et al. (2007) Preparation, application and testing of permanent antibacterial and antiviral coatings. Nature Protocols 2 (10), 2412-2417
4 Green, J.B. et al. (2011) Review of immobilized antimicrobial agents and methods for testing. Biointerphases 6 (4), CL2-43
5 JIS Z 2801:2000 Antimicrobial Products – Test for Antimicrobial Activity and Efficacy. Japanese Standards Association, Tokyo, Japan
6 Vreuls, C. et al. (2010) Biomolecules in multilayer film for antimicrobial and easy-cleaning stainless steel surface applications. Biofouling 26 (6), 645-656
7 ISO 22196:2011 Measurement of antibacterial activity on plastics and other non-porous surfaces. International Organization for Standardization, Geneva, Switzerland
8 ASTM E2149-13a Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions. American Society for Testing and Materials
9 AATCC Test Method 100, Antibacterial Finishes on Textile Materials: Assessment of. Technical Manual of the American Association of Textile Chemists and Colorists
10 Swofford, H.W. (2010) An Overview of Antimicrobial Testing for Textile Applications. AATCC Review November/December, 51-55 (PDF 234 KB)
11 JIS L 1902:2015 Textiles – Determination of antibacterial activity and efficacy of textile products. Japanese Standards Association, Tokyo, Japan
12 AATCC. Test Method 147, Antibacterial Activity Assessment of Textile Materials: Parallel Streak Method. Technical Manual of the American Association of Textile Chemists and Colorists
13 ISO 20743:2013 Textiles – Determination of antibacterial activity of antibacterial finished products. International Organization for Standardization, Geneva, Switzerland
14 OECD. (2008) Guidance Document on the Evaluation of the Efficacy of Antimicrobial Treated Articles With Claims For External Effects. ENV/JM/MONO(2008)27 (PDF 282 KB)
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