Growth viability assay assessment for disinfectant screening

Disinfectant screening is an important step for manufacturing and approval of disinfectants. Screening helps identify the effectiveness, target microbe, minimum inhibitory concentration, and contact time. A standard screening test must be able to assess these parameters effectively over a broad range of formulations and microbes. Currently, there is no unified method to analyze disinfectants, a standard test is selected based on the application. This project aimed to identify a standard method that can be used over a broad range of microbes irrespective of disinfectant composition. Microbicidal activity of Hydrogen peroxide and Quaternary ammonium-based disinfectants was evaluated by Fluorescein diacetate (FDA), Methyl tetrazolium (MTT), and growth assays. M. terrae and C. albicans pellets were formed in 96 well plates. In comparison to FDA and MTT assay, growth assay was more accurate and had a larger range. It required no chemical reagents, thus eliminating interaction with disinfectant components. Therefore, growth assay can potentially be used as a unified method for disinfectant studies. Further tests on a broader range of microbes and field studies have to be conducted to confirm this claim.