EPA Residual Self-Sanitizing Activity of Dried Chemical Residues on Hard Nonporous Surfaces

Test Purpose

The EPA Residual Self-Sanitizing Activity of Dried Chemical Residues on Hard Nonporous Surfaces is a carrier-based test method used to evaluate residual self-sanitizing activity (e.g. significant reduction in numbers of microorganisms which may be present or subsequently deposited) on treated, dry surfaces. Products with these label claims are typically registered with the U.S. EPA.

Test Summary

In this method, a series of glass or stainless steel surfaces are treated with the product and the product is allowed to dry over the surfaces. The treated surfaces then undergo a series of physical wear procedures followed by systematic low-level inoculation of test organism to simulate routine use and contamination of the surface. After completion of the wear cycles, the treated surfaces are inoculated with the test organism to evaluate the residual sanitizing efficacy of the surface and the survivors are quantitatively assayed. The resulting plates are incubated, enumerated and a percent and log10 reduction is determined as compared to a population control. In order to successfully demonstrate residual self-sanitizing efficacy, the product must demonstrate a 99.9% reduction after 24 hours following application. Typical test organisms include Staphylococcus aureus and Enterobacter aerogenes or Klebsiella pneumoniae. Additional pathogens of clinical, occupational or household relevance are often tested as well.