The ISO 20743 standard is an international test method that specifies procedures for evaluating the antibacterial activity of textile products. This standard is intended to provide a definitive evaluation of textiles treated with antibacterial finishes under various conditions.

Different from AATCC 100, which is commonly used in the United States, ISO 20743 is globally recognized and provides various testing options to accommodate different types of antibacterial agents and diverse textile products, such as woven fabrics, knitted fabrics, and non-wovens.

   General Procedure

The general procedure involves these main steps:

1.  Sample Preparation : Both treated textile samples and untreated control samples are prepared according to the guidelines specified in the standard.

2.  Inoculation : A specified amount of bacterial suspension, usually containing strains like Staphylococcus aureus or Klebsiella pneumoniae, is applied to the textile samples.

3.  Incubation : The inoculated samples are incubated for a particular time and at a specified temperature, as outlined in the standard.

4.  Enumeration : Post incubation, the bacteria are retrieved from the samples, and the remaining bacterial population is counted using standard microbiological techniques.

5.  Calculation and Interpretation : The antibacterial activity is calculated by comparing the bacterial counts on the treated sample versus the untreated control. The results are usually reported as a percentage reduction in bacterial population.

   Testing Methods

ISO 20743 provides options for different test methods, such as:

-  Absorption Method : This involves absorbing the bacterial suspension into the textile and assessing the antibacterial activity by enumerating the surviving bacteria.
  
-  Transfer Method : In this approach, bacteria are placed in direct contact with the textile, often through a sandwich configuration, and the transfer of bacteria is measured.

-  Printing Method : Used for textiles with patterns, where bacteria are applied to specific locations, and their survival rate is measured.

   Evaluation

The performance of the textile is usually evaluated based on the following criteria:

-  Efficacy : The percentage reduction of bacterial population is calculated, and the effectiveness of the antibacterial treatment is assessed based on this.

-  Durability : Sometimes the textile samples are laundered multiple times to check the durability of the antibacterial finish.

   Importance

ISO 20743 is essential for manufacturers who want their textile products to be accepted internationally. It provides a standard approach to evaluating antibacterial activity, helping to ensure that products meet consistent quality and performance criteria.

As with any standard, the specific procedures and conditions are outlined in detail in the official documentation. Therefore, it's crucial to consult the most recent version of the ISO 20743 standard for accurate and complete information.