AOAC 961.02

Germicidal Spray Products as Disinfectants

Summary

AOAC 961.02 Germicidal Spray Products as Disinfectants method is the standard test method required by the U.S. Environmental Protection Agency for validating disinfectant claims. The tests are designed to evaluate the antimicrobial efficacy of spray products (both dilutable and ready to use liquids) on hard, non-porous surfaces contaminated with bacteria.

Testing for basic efficacy claims is divided into the following categories:

• Limited Spectrum: for products with limited efficacy; effective against Gram-negative (Salmonella enterica) or Gram-positive bacteria (Staphylococcus aureus), but not both.
• General or Broad Spectrum: for products having efficacy against both Gram-negative (Salmonella enterica) and Gram-positive bacteria (Staphylococcus aureus)
• Hospital or Healthcare Disinfectants: for testing of products recommended for use in hospitals, clinics, dental offices, nursing homes, or any other healthcare-related facility; products must have efficacy against both Staphylococcus aureus and Pseudomonas aeruginosa.

Once a product establishes efficacy as a broad spectrum or hospital/healthcare disinfectant, the product may be tested against additional microorganisms (any bacteria claimed on the label in addition to the base claim) including fungi, Mycobacterium, and viruses.

Test Overview

• Sterile 1” x 1” surfaces (“carriers”) are contaminated with microorganisms.
• Inoculated carriers are sprayed with the disinfectant and held for the appropriate exposure time (this will be the time the EPA allows on the product label and must be 10 minutes or less).
• At the completion of the exposure period, the treated carriers are transferred to recovery broth with neutralizers. 
• The treated/neutralized carriers are incubated and observed for the presence of growth.

Non-GLP screening for R&D purposes can be tested using 10, 30, or 60 carriers against multiple batches at various exposure times. 

60 replicates per microorganism are tested against three batches of the disinfectant for initial product registration. 

For Staphylococcus aureus: growth must be observed in ≤1 replicates out of 60 for each lot to demonstrate efficacy.

For Pseudomonas aeruginosa: growth must be observed in ≤1 replicates out of 60 for each lot to demonstrate efficacy.

For Salmonella enterica: growth must be observed in ≤1 replicate out of 60 for each lot to demonstrate efficacy.

10 replicates per microorganism are tested against two batches of the disinfectant for fungi (Trichophyton interdigitale) and confirmatory testing and testing of additional organisms. 

Growth must not be observed in any replicate out of 10 for each lot to demonstrate efficacy.