Work Item
ASTM WK80644

New Test Method for Evaluating the Performance of Antimicrobials in or on Polymeric Porous and Non-porous Materials Against Staining by Streptomyces species (A Pink Stain Organism)

1. Scope

1. Scope
1.1 This method is intended to assess susceptibility of polymer materials, as well as products that may directly contact the treated polymer, to staining by the Actinomycete Streptomyces species.
1.2 This test method is also suitable for evaluating dark-pigmented test samples since the bacterial growth inhibition can be assessed.
1.3 Familiarity with microbiological techniques is required. This test method should not be used by persons without at least basic microbiological training.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.


antimicrobial efficacy; pink stain; plastics; polymeric non-solids; Streptomyces


When certain bacteria and mold species grow on the surface of non-rigid, flexible or “plasticized” polymers, metabolites such as pigments in the case of certain bacteria and melanin (dark stains from fungal growth) cause undesirable stains on the polymer surface. These stains may persist even after the surface growth is removed. This test method is used to determine the performance of antimicrobial agents used in or on synthetic polymeric porous and non-porous materials against staining by the Actinomycete, Streptomyces species. This organism has been chosen as an indicator organism, although other organisms have been known to cause undesirable staining in polymeric porous and non-porous materials.

The title and scope are in draft form and are under development within this ASTM Committee.


Developed by Subcommittee: E35.15

Committee: E35

Staff Manager: Brian Milewski

Work Item Status

Date Initiated: 01-24-2022

Technical Contact: Leon Estell