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ISO 20743 Antibacterial Textile Testing (Antibacterial Activity of Textile Products)
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Summary
ISO 20743 is an internationally recognized test method used to evaluate antibacterial performance of treated textiles. This test method compares bacterial growth reduction on a textile sample to an untreated control sample. It generates log reduction data that helps textile manufacturers to support antibacterial performance claims. The standard applies to both woven and non-woven materials, including finished and treated textiles.
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Quick understanding about test
ISO 20743: 2013 Test Protocol – Determination of Antibacterial Activity of Textile Products
Applicable to all textile products including clothing, wadding, home furnishings and more. See all
- Staphylococcus aureus (ATCC 6538P)
- Klebsiella pneumoniae (ATCC 4352).
- The sample material is inoculated with a suspension of bacteria and incubated for a specific time duration.
- After incubation, samples are neutralized with a suitable neutralizing solution.
- Bacteria recovered in neutralizing solution are subjected to serial dilution, followed by plating and incubation.
- Helps manufacturers comply with international regulations
- Provides reproducible data on products claims and efficacy
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What is ISO 20743?
ISO 20743 specifies standardized quantitative test methods for determining the antibacterial activity of all textile products, including woven and nonwoven materials.
ISO 20743 and JIS L 1902 are the most commonly used test methods to determine the antimicrobial activity of textile clothes. These two methods are very identical technically but are named by two different organizations. JIS stands for Japanese Industrial Standard (JIS) and ISO stands for International Organization for Standardization. At MIS, we perform both of these test methods to check the efficacy of antibacterial-treated clothes.
ISO 20743 Test method overview
ISO 20743 test method describes three different inoculation techniques
- Absorption method (most commonly used)
- Inoculation: Test bacterial suspension is directly inoculated onto the test specimens.
- Transfer method
- Inoculation: Bacterial suspension is inoculated on agar plates and then transferred to the textile specimens.
- Printing method Printing Bacteria: Test bacteria are printed onto specimens using a filter.
ISO 20743 Test procedure step-by-step
Sample preparation and sterilization
- Test Samples: 6 antibacterial-treated fabrics and 6 control (untreated) fabrics.
- Sterilization: All test samples must be sterilized to avoid contamination.
Inoculation with test bacteria
Inoculation: Test bacterial suspension of a known titre is inoculated onto the sample material. Any one of the three inoculation methods available is used to determine the antibacterial activity of the treated textiles.
At MIS, our experts use the “absorption method” to determine the antibacterial activity of treated samples.
Incubation conditions
- Zero-minute titre determination
- Both control and treated samples (3 each) are immediately washed with 20 ml of neutralizing media (Soya Casein Digest Lecithin Polysorbate Broth, SCDLP) after bacterial inoculation.
- Extended incubation
- The remaining six specimens (3 control and 3 testing samples) are incubated at 37°C ± 2°C for 18 to 24 hours with the test bacterial suspension.
Neutralization and Enumeration
- After incubation, the reaction is stopped by adding 20 ml of neutralizing media (SCDLP) to the tubes, followed by shaking to ensure proper mixing.
- Serial dilution and plating of the bacterial suspension from each tube are performed.
- The decrease in microbial growth is compared to the control fabric.
ISO 20743 results and log reduction interpretation
ISO 20743 does not specify any universal “pass or fail” criteria. The antibacterial activity is reported as:
- Log reduction value
- Bacterial reduction percentage
The results are usually reported as :
Reduction Level | Interpretation |
90% reduction | Moderate antibacterial activity |
99% reduction | Strong antibacterial activity |
99.9% reduction | High antibacterial activity |
Criteria for acceptance is usually set by brand requirements, regulatory guidelines or product specifications.
ISO 20743 vs AATC 100 vs JIS L 1902
Parameter | ISO 20743 | AATCC 100 | JIS L 1902 |
Origin of Standard | International Organization for Standardization | American Association of Textile Chemists and Colorists | Japanese Standards Association |
Inoculation method | Three inoculation methods | Single method | Single method |
Result type | Quantitative (No defined pass/fail criteria) | Quantitative (No defined pass/fail criteria) | Both Quantitative and Qualitative |
Recognition and Acceptance | Internationally recognized and Accepted | Primarily North America | Primarily Japan and Asian markets |
Applications of ISO 20743 testing
ISO 20743 test method applies to all textile products regardless of the type of antibacterial agents. It includes –
- clothes,
- waddings,
- threads,
- bedclothes,
- home furnishings,
- and miscellaneous goods.
Test organisms used in ISO 20743
Mandatory strains
Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538P)
Additional strains
Enterococcus hirae (ATCC 10541), Klebsiella pneumoniae (ATCC 4352), MRSA (ATCC 33591), Salmonella enterica (ATCC 10708), Candida albicans (MTCC 3017).
Strengths of the ISO 20743 Test Method
- It is a quantitative test that ensures consistent and reproducible results.
- The method tests for both bacteriostatic (growth-inhibiting) and bactericidal (bacteria-killing) properties of the antimicrobial-treated textile fabric.
- Uses standardized microbial concentrations and provides nutrient-rich conditions during incubation to rigorously challenge the antimicrobial efficacy.
- The test is conducted in triplicate, ensuring the results are reproducible.
Why MIS?
At Microbe Investigations Switzerland, we specialize in ISO 20743 testing, helping you verify the antibacterial performance of your textile products. Our state-of-the-art testing facilities and expert team provide comprehensive, reliable, and accurate evaluations, ensuring your products are safe, effective, and compliant with international standards.
Request ISO 20743 testing
To learn more about our ISO 20743 antimicrobial testing services or to schedule a consultation, contact our team today.
Frequently Asked Questions
DR. Martinoz Scholtz
Antibacterial activity in textiles is measured by following standardized test procedures like ISO 20743, AATCC 100 or JIS L 1902. The procedure typically involves inoculating textiles with bacteria, incubating and then measuring the bacterial growth reduction.
This test method applies to all textile products such as cloth, wadding, thread, bedclothes, home furnishings, and miscellaneous goods.
It takes 7-8 days to complete the test.
At Microbe Investigations Switzerland, we perform this test using the following bacteria: Pseudomonas aeruginosa (ATCC 15442), Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538P), Enterococcus hirae (ATCC 10541), Klebsiella pneumoniae (ATCC 4352), MRSA (ATCC 33591), Salmonella enterica (ATCC 10708), Candida albicans (MTCC 3017). Additional strains can be tested on request.
A 3-log reduction means the bacterial population is decreased by 99.9% which in turn indicates high antibacterial activity.
Both standards are equally reliable but selection depends on your target market and regional regulatory requirements.
ISO 20743 uses 3 different inoculation methods and is internationally accepted while AATCC 100 uses one standardized method and is usually referred to in North America.
Textile products must show a significant decrease ( 2 log reduction or above) in bacterial load on the test fabric compared to the control fabric to pass this test.
Yes. This test can be used to compare the antibacterial efficacy of various treatments by assessing their antibacterial activity against a standard control.
No, ISO 20743 is specifically designed to test the antibacterial efficacy of textiles. Other standards such as ISO 18184 and AATCC 30 can be used to measure antiviral or antifungal efficacy of textiles.
Yes. The results provide scientifically validated data that can substantiate antibacterial claims and help meet regulatory requirements for product efficacy and safety.
Several factors can affect the antibacterial testing of textiles including textile composition, finish durability, test conditions such as temperature and humidity.
Antibacterial testing is required for textile products claiming antibacterial activity to meet regulatory requirements and for commercial launch.
Bacterial strains used for testing are selected based on the product’s intended use environment. Common strains used in this test method are Staphylococcus aureus and Escherichia coli
Antibacterial textile testing is commonly required in industries where hygiene, odor control, infection prevention, and product longevity are critical. The primary sectors include healthcare, sportswear, home textiles, and specialized protective industries.
Antibacterial finishes either kill the bacteria (Bactericidal) or inhibit bacterial growth (Bacteriostatic). They disrupt bacterial cell membranes, interfere with their metabolism or prevent attachment to the textile surface.
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