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Disinfection Efficacy Studies

Disinfectant tests are used to validate sanitizing agents for effectiveness against organisms, which is an increasing area of concern to manufacturers and regulatory agencies. Disinfectant efficacy must be established before a new disinfectant can be put on the market. Additionally, manufacturers must validate disinfectant regimens for cleanrooms and other controlled areas.

Materials tested typically include household and industrial disinfectants, sporicides, fungicides, and hand sanitizers. Disinfectant testing is conducted per many different standards including The Official Methods of Analysis of AOAC International and USP General Chapter 1072. We are highly experienced in performing general disinfectant efficacy tests to establish kinetic kill curves for a large variety of organisms.

Applicable Standards

  • The Official Methods of Analysis of AOAC International
  • USP General Chapter 1072

Testing Locations

Study Outline

The disinfectant validation test is to ensure that the cleaning and disinfectant procedure conducted for a controlled room is sufficient to prevent the microbial contamination on objects or surfaces. The USP chapter <1072> provides guidance on a disinfectant regimen in relation to the reduction of viable microorganisms and spores. Environmental isolates are commonly used to validate the disinfectant program used by the sponsor at their site. A validation verifies that the cleaning and disinfectant program used by the sponsor and followed during the validation is effective and appropriate for the surfaces and controlled environment. The risk of a manufacturer not conducting a cleaning and disinfection validation may lead to an FDA 483, warning letter, or the possible release of unsafe product. Nelson Labs has the capability to customize protocols to meet sponsor’s hard-surface disinfectant validation needs.

In the Disinfectant test procedure, representative surfaces that are scaled down for laboratory testing are referred to as “coupons.” The test coupons must be allow for sterilization.

The sterile coupons are challenged with 10 – 30 µL of culture or spore suspension. The suspension is spread evenly over a 1-square-inch area and then dried. The challenge culture may include an organic soil such as 5% blood serum to further the difficulty of disinfection, upon request.

The validation test is intended to validate the actual disinfection process that the sponsor uses in their facility. Nelson Labs is well versed in many application methods and can adjust to suit the sponsor’s testing needs. Examples of disinfectant application include spraying directly or wiping with a sterile towel saturated with the disinfectant. The exposure time during which the disinfectant is in contact with the inoculated coupons can also be adjusted to meet the sponsor’s methods.

Following the disinfection procedure, the treated coupons are aseptically transferred to neutralizing media and extracted to remove any surviving microorganisms. The number of surviving organisms are assayed and enumerated and percent and log reduction values are calculated. The panel of organisms selected for this test may also vary with recommendation for use of environmental isolates from sponsor’s specific facilities. It is recommended that a spectrum of representative organisms be selected for the test, including but not limited to: Gram-positive bacteria, Gram-negative bacteria, fungi, mold spores, and Gram-positive spore-forming bacteria. Best industry practice is to perform the test using environmental isolates.

Neutralization validation of the test disinfectants and extraction efficiency testing are included in every test for each organism/disinfectant/coupon combination tested, as well as positive and negative controls. Neutralization testing proves that the assay method used adequately neutralizes any antimicrobial agent in the product that could interfere with testing.

If you have additional questions about Disinfection Efficacy Studies, or would like to consult with the experts at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.