Key Summary Points
- ISO 20743 and AATCC 100 are standard test methods that evaluate antibacterial activity of textile materials
- ISO 20743 includes three different inoculation methods (absorption, transfer and printing) to simulate different conditions
- AATCC 100 describes a single quantitative test which compares treated and untreated fabrics after a defined contact period
- Both methods measure bacterial reduction using colony counts
- ISO 20743 is widely used globally, while AATCC 100 is commonly used in North America
Summary
ISO 20743 and AATCC 100 are both test standards used to evaluate the antibacterial activity in textile products. ISO 20743 provides three different inoculation methods to simulate different textile use conditions, while AATCC 100 measures bacterial reduction using a single quantitative test. Both methods help manufacturers validate antibacterial performance of treated fabrics.
Why does antibacterial testing for textiles matter?
Very frequently, textiles come in contact with skin, moisture and microorganisms in the environment. These interactions allow bacterial growth on textiles, that leads to odor, textile degradation and hygiene issues.
To prevent this, many textile products such as medical textiles, sportswear, bedding and consumer apparel are incorporated or applied with antibacterial treatments. However, to claim they are antibacterial, manufacturers must validate those claims with testing methods.
That is where test standards ISO 20743 and AATCC 100 come in.They are quantitative tests that help measure antibacterial activity of textiles by comparing bacterial growth on treated and untreated textiles. These tests scientifically support antimicrobial textile claims.
What is ISO 20743?
ISO 20743 is a test standard used that quantitatively determines the antibacterial activity of textile products. The method assesses how effectively a textile inhibits bacterial growth under controlled conditions in the laboratory. This test compares the number of bacteria recovered from antibacterial-treated textiles with untreated textiles post incubation to provide scientific evidence for claiming antibacterial performance.
Scope of ISO 20743
ISO 20743 is applicable to a wide range of textiles incorporated with antibacterial agents. It is applicable to both built-in antimicrobial fibres and post treatment coatings or finishes.
The standard can be used for:
- Woven fabrics
- Knitted textiles
- Non-woven fabrics
- Yarns
- Textiles used in Apparel, Home furnishings and Medical settings
Inoculation methods in ISO 20743
Iso 20743 uses three types of inoculation methods which simulate different real-world contamination conditions and textile surface properties. Among the three, selection of a method depends on structure of the textile, absorption characteristics and product use conditions.
- Absorption method – It is the most used method among the three. In this method, the test bacteria is directly inoculated onto the specimen.
- Transfer method – It is the method in which the test bacteria are placed on an agar plate and then transferred on to the specimen
- Printing method – It is the method in which the test bacteria are placed on a filter and printed on specimens by pressing the filter onto the test specimen.
ISO 20743 test procedure
Test procedure for ISO 20743 is as follows:
- Test samples and control samples are sterilized and prepared for the test procedure
- Test bacteria are inoculated onto the test specimen through any one of the 3 inoculation methods
- After inoculating, the samples are incubated at specified temperature and humidity for 18-24 hours
- Post Incubation, remaining bacteria are extracted from the specimen using a neutralizing solution
- Recovered bacteria are plated on agar and incubated to determine colony-forming units (CFU)
- The bacterial reduction in the treated fabric is calculated in comparison to the control sample
What is AATCC 100?
AATCC 100, published by American Association for Textile Chemists and Colorists(AATCC), is a test to quantitatively evaluate the antibacterial activity of treated textiles by comparing the bacterial counts before and after a specified contact time.
The method is widely used in North American textile testing and certification programs.
Scope of AATCC 100
AATCC 100 is applicable to antibacterial treated textile materials
They include:
- Treated apparel textiles
- Medical textiles
- Household textiles
- Odor-control sportswear
- Upholstery textiles
Single inoculation method in AATCC 100
Unlike ISO 20743, AATCC 100 uses a single standardized method of inoculation during the test procedure
AATTC 100 test procedure
The test procedure for AATCC 100 is as follows:
- Test samples and control samples are sterilized and prepared for the test procedure
- A specified concentration of bacteria is inoculated onto the textiles
- The test and control specimens are both incubated for specified period, typically 24 hours
- Post Incubation, the remaining bacteria are extracted using a neutralizing solution
- Neutralized solution is plated and incubated to determine colony counts
- The bacterial reduction is calculated and compared with control sample
Passing criteria for AATCC 100 and ISO 20743
Both standards do not specify a universal โpass or failโ 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 performance |
Acceptance criteria are often determined by brand requirements, regulatory guidelines, or product specifications.
Key similarities between ISO 20743 vs AATCC 100
- Objective: Both standards aim to quantify the antibacterial activity on textiles ensuring the treated fabrics meet health and hygiene standards.
- Methodologies : Both the AATCC 100 and ISO 20743 tests are quantitative methods used to evaluate the antimicrobial activity of textile products.
- Mandatory Test Strains: Each standard recommends testing against common bacteria strains such as Staphylococcus aureus and Klebsiella pneumoniae among others.
- Scope of Products: They are applicable to a broad range of textile products including those used in healthcare, consumer goods, and industrial applications.
Technical differences between ISO 20743 vs AATCC 100
Origin of standard โ
- ISO 20743 has been created by the International Organization for Standardization to measure the antimicrobial activity of textile products.
- AATCC 100 was created by the American Association of Textile Chemists and Colorists (AATCC). The AATCC 100 is an industry standard for the evaluation of textile products mainly focused on the North American market but also applicable to international markets.
Test Methodology
- ISO 20743 outlines three distinct inoculation methods for assessing antimicrobial activity in textiles: the absorption, transfer and printing methods. Each method is described in terms of how bacteria are applied to the fabric and the conditions under which the fabric is incubated.
- AATCC 100 focuses on a single standardized test for evaluating antibacterial activity of textile
Key technical differences between ISO 20743 vs AATCC 100
| Parameter | ISO 20743 | AATCC 100 |
| Origin | International Organization for Standardization | American Association of Textile Chemists and Colorists |
| Inoculation method | Three inoculation methods | Single quantitative method |
| Global Acceptance | International | North America |
Where are ISO 20743 and AATCC 100 tests used?
- Antibacterial hospital textiles
- Antibacterial bedding and matresses
- Home furnishing, bedding, curtains
- Consumer apparel
Regulatory considerations
Antibacterial textile products must comply with chemical and product safety regulations in the markets where they are sold. When antimicrobial agents are used in fabrics, the substances themselves may be regulated and require approval or registration.
In the United States, antimicrobial treatments are regulated by the U.S. Environmental Protection Agency under the Federal Insecticide, Fungicide, and Rodenticide Act. In the European Union, antimicrobial-treated textiles must follow the Biocidal Products Regulation (EU) No 528/2012 administered by the European Chemicals Agency.
Manufacturers must ensure that antibacterial claims are supported by appropriate laboratory testing, such as ISO 20743 or AATCC 100, and that product labeling complies with applicable regulations. Proper documentation and test reports are typically maintained to demonstrate compliance during certification, export, or regulatory review.
Choosing between ISO 20743 and AATCC 100
The choice between the methods typically depends on target market, product type and testing objective.
ISO 20743 maybe preferred to:
- Test textiles for global markets
- Evaluate different contamination scenarios
- Test various fabric structures
AATCC 100 maybe preferred when:
- Testing textiles for markets in North America
- A standardized single method is required
Many manufacturers test their textiles in accordance with both tests to support global product claims.
When should you consider additional testing?
Additional testing may be required when evaluating:
- Durability after repeated washing
- Anti odor performance of textiles
- Real-use simulation testing
- Safety and toxicity testing
Complementary standards may include:
- AATCC 61 (wash durability)
- ISO 17299-3A
Why choose MIS
If you are in the process of developing antibacterial textiles, we can help you ensure your data stands up to scrutiny firmly.
Our expert microbiology team at MIS performs the test with strict environmental control to generate accurate, reproducible data for antibacterial claims.Our reports are clear, audit-ready, and structured to support regulatory submissions and product claims.
Get in touch and letโs get your product verified the right way.
Conclusion
Antibacterial testing for textiles plays an important role in validating the antibacterial claims.
Test standards such as ISO 20743 and AATCC 100 provide reliable method to evaluate bacterial reduction in textiles claiming antibacterial activity. While ISO 20743 offers flexible inoculation approaches to simulate different contamination scenarios, AATCC 100 provides a standard quantitative method widely referred to in North America.
Antibacterial textile testing plays a crucial role in verifying the performance of antimicrobial fabrics.
Selection of appropriate test methods to validate results helps manufacturers support antibacterial claims, improve product quality and ensure consumer safety.
FAQs
1.What is the difference between ISO 20743 and AATCC 100?
ISO 20743 and AATCC 100 both test for antibacterial activity of the textiles. ISO 20743 describes three different inoculation methods to simulate different contamination conditions. Whereas AATCC 100 uses a single standardized quantitative procedure.
2.Which standard is preferred for antibacterial textile testing in North America?
AATCC 100 is the preferred method for North America
3.Does AATCC 100 evaluate durability after washing?
No, separate laundering durability tests must be performed to evaluate such properties.
4.Can antimicrobial fabrics be tested using both standards?
Yes. Many textile manufacturers perform both ISO 20743 and AATCC 100 testing to support antimicrobial claims across global markets. Both methods can be used when products are sold in multiple markets or when buyers require testing according to specific standards.
5.Do ISO 20743 tests simulate real-world wear conditions?
ISO 20743 describes three different inoculation methods used to simulate different contamination conditions to closely represent real world usage conditions.
