Development and Testing of a Microbiological Assay To Detect Residual Effects of Disinfectant on Hard Surfaces

We describe a glucuronidase bioassay for detecting residual bactericidal activity from the use of disinfectants on hard surfaces; in this assay we used formaldehyde, ethanol, isopropanol, chlorine, and a commercial preparation containing 2-bromo-2-nitro-1,3-propanediol. Chlorine and the commercial preparation showed bactericidal activity (53.5% and 98.2%, respectively) for a week after disinfection.