Textiles — Determination of antibacterial activity of textile products

 

Introduction

Specialty products of antibacterial-treated textiles have been introduced in the market and are expanding year by year in various applications. These textiles meet the consumer's requirement to seek prevention of, and protection from, the negative effects caused by bacteria, which in turn secures the quality of life.

This established a substantial need for an International Standard which covers test methods to determine the antibacterial activity for antibacterial textile products.

A qualitative test method for antibacterial activity was developed as ISO 20645. At the time, there were no testing standards for the quantitative method which gives more objective information for the antibacterial activity of the textile products.

Although there are 6 ways for the combination of inoculation methods and quantitative measurements to execute this test, the choice of the ways depends on the user's availability and consensus between the concerned parties.

1   Scope

This document specifies quantitative test methods to determine the antibacterial activity of all antibacterial textile products including nonwovens.

This document is applicable to all textile products, including cloth, wadding, thread and material for clothing, bedclothes, home furnishings and miscellaneous goods, regardless of the type of antibacterial agent used (organic, inorganic, natural or man-made) or the method of application (built-in, after-treatment or grafting).

This document covers three inoculation methods for the determination of antibacterial activity:

a) absorption method (an evaluation method in which the test bacterial suspension is inoculated directly onto specimens);

b) transfer method (an evaluation method in which test bacteria are placed on an agar plate and transferred onto specimens);

c) printing method (an evaluation method in which test bacteria are placed on a filter and printed onto specimens).

NOTE Based on the intended application and on the environment in which the textile product is to be used, and also on the surface properties of the textile properties, the user can select the most suitable inoculation method.

 

This document also specifies the colony plate count method and the adenosine triphosphate (ATP) luminescence method for measuring the enumeration of bacteria.

2   Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 6330, Textiles — Domestic washing and drying procedures for textile testing

3   Terms and definitions

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at http://www.electropedia.org/

3.1

control fabric

fabric used to validate the growth condition of test bacteria and validate the test

Note 1 to entry: The same fabric as the fabric to be tested but without antibacterial treatment or a 100 % cotton fabric without fluorescent brighteners or other finish can be used.

3.2

antibacterial agent

product designed to prevent or mitigate the growth of bacteria, to reduce the number of bacteria or to kill bacteria

3.3

antibacterial finish

treatment designed to prevent or mitigate the growth of bacteria, to reduce the number of bacteria or to kill bacteria

3.4

antibacterial activity

activity of an antibacterial finish (3.3) used to prevent or mitigate the growth of bacteria, to reduce the number of bacteria or to kill bacteria

3.5

plate count method

method in which the number of bacteria present after incubation is calculated by counting the number of colonies according to a ten-time dilution method

Note 1 to entry: The results are expressed in “CFU (Colony Forming Unit)”.

3.6

luminescence method

method in which the amount of ATP contained in bacterial cells is measured

Note 1 to entry: The results are expressed in “moles of ATP”.

3.7

neutralizer

chemical agents used to inactivate, neutralize or quench the antibacterial properties of antibacterial agents (3.2)