WARNING — Handling and manipulation of microorganisms which are potentially hazardous requires a high degree of technical competence and may be subject to current national legislation and regulations. Only personnel trained in microbiological techniques should carry out such tests. Appropriate practices for disinfection, sterilization and personal hygiene must be strictly observed. This International Standard specifies a method of evaluating the antibacterial activity of antibacterial-treated plastic products (including intermediate products). NOTE It may also be suitable for other non-porous materials. It is not intended to be used to evaluate the effects and propagation of bacteria on plastics without antibacterial treatments. ISO 846 [6] describes tests to evaluate the effects and propagation of bacteria on plastics, which are different from those covered by this International Standard. Those who are interested are referred to ISO 846:1997, method C. Secondary effects of antibacterial treatments, such as the prevention of biodeterioration and odour, are not covered by this International Standard, which is not intended to be used or referenced as a method to document or claim biodegradability of plastics. For biodegradation, refer to ISO 14851, ISO 14852 and ISO 14855 (see the Bibliography) and related standards. This International Standard does not concern plastic building materials, such as PVC or composites, unless they act in the same way as treated articles. Any results obtained with this International Standard should always refer to this standard and the conditions used. Results obtained with this International Standard indicate antibacterial activity under the specified experimental conditions used herein, and do not reflect activity under other circumstances where a variety of factors, such as temperature, humidity, different bacterial species, nutrient conditions, etc., have to be considered. A minimum diffusion of the antibacterial agents/chemicals into the test inoculum is necessary with this procedure. It is recommended that workers consult ISO 7218.