5.1 Porous articles (often textiles) are often treated with antimicrobial agents to reduce the growth of microorganisms during use, in storage, or while waiting to be laundered, or both. Additionally, antimicrobial agents are added to reduce or control the overall microbial growth on porous articles that may affect the material's odor, visual, chemical or physical integrity, or both.

5.2 Antimicrobial textile test methods that measure the antimicrobial behavior of treated textiles do exist but they are often specific for one type of antimicrobial agent or are designed to or may artificially (not expected in real life) promote the release of some specific antibacterial agents over others. This test method is designed to be able to measure the antimicrobial activity from all common antimicrobial agents used to treat porous articles, including textiles, without giving either positive or negative bias to one type of chemistry or product over another.

5.3 In an effort to avoid excessive use or abuse of antimicrobial agents in the environment, it is important to understand if untreated porous articles are susceptible to microbial contamination and growth. In this test method, a small amount of nutrients is added to each test sample in order to promote some microbial growth on susceptible test samples but not enough to overwhelm potential antimicrobial agents that may be effective in real life situations. Furthermore, low levels of nutrients allow investigators to add soiling agents that may be more reflective of a specific treated product's end use or expected performance.

5.4 Very specific parameters are identified within this method to limit any variability that may be seen between laboratories. Identifying and clarifying potential variables found in other guides or methods used in the industry will allow for better reproducibility and repeatability between and within laboratories.

5.5 This test method provides the foundation for conducting tests on porous antibacterial treated articles. Modifications of this method that simulate intended use, durability and compatibility of the treated article should be outlined to ensure an accurate assessment of antimicrobial activity with each particular biocide that substantiates end use claims made for the article. A list of these typical modifications and current test methods for textiles can be found in Guide E2922.

5.6 This test method is appropriate for porous materials such as textiles, paper, or similar porous materials. It is intended to measure the antibacterial properties of such materials. In most instances, further studies will be required to support and substantiate actual claims being made for the performance of treated materials in practice or as part of a regulatory process.

5.7 This test method or indicated modifications may be used to determine antimicrobial activity as indicated in 5.6 or may be used as a routine bioassay in standard quality control programs.