OECD Quantitative Disk Carrier Test Method (Modification of ASTM Method E2197)

Purpose of Test

The OECD Quantitative Method for Evaluating the Activity of Microbicides used on Hard Non-Porous Surfaces is a carrier-based test method designed to evaluate liquid chemicals for bactericidal, mycobactericidal and fungicidal activity. The original intent in devising this method was to provide a harmonized method that was internationally recognized between OECD member countries. The method has now been implemented only as a guidance document which will likely be recognized by the U.S. EPA as a means to evaluate disinfectants.

Summary of Test

In this method, a series of stainless steel disks are inoculated with the test organism. The carriers are desiccated and subsequently treated with a sample of the liquid disinfectant. After exposure, the carriers are neutralized and quantitatively assayed for surviving test organism. The resulting plates are incubated, the number of survivors is enumerated and a percent and log10 reduction is determined as compared to a population control. No regulated performance criteria has yet been established by the U.S. EPA however products may be evaluated using this method to investigate product performance. Common test organisms include Staphylococcus aureus, Enterococcus hirae and Pseudomonas aeruginosa.