A lot of disinfectants have faster dwell times. Do janitors really need to allow for a 10-minute dwell time?

According to the U.S. Environmental Protection Agency (EPA), using a pesticide (disinfectant) in a manner that is inconsistent with the use directions on the label is a violation of the Federal Insecticide, Fungicide and Rodenticide Act and can result in enforcement actions to correct the violations. It has been said, “The Label is the Law.” If a disinfectant label requires 10-minute dwell time, then it is required. – Facilities Supplies, Rochester Midland Corporation, Rochester, New York

There is definitely a lot of variation between products. Dwell time is very product specific. Testing is done to establish log reduction values over time for a disinfectant against selected bacteria, fungi and/or mold and for the specific amount of time the disinfectant must be in contact with the surface to kill the microbes.

The term “log” stands for logarithm, which is an exponent of 10. A 1-log kill would represent a 90 percent reduction in numbers of live bacteria on a surface. A 4-log kill would represent a 99.99 percent reduction on the surface. A product claiming a 99.99 percent reduction compared to a product claiming a 99.9999 percent germ reduction may require a longer dwell time. In critical care areas, the higher log kill may be more beneficial than a short dwell time.

This is why it is important to thoroughly read the label for a specific efficacy claim and the required dwell time to eliminate a specific organism. Broad spectrum disinfectants have multiple claims but do not often eliminate all surface contamination. Total elimination of all microbial life on a surface requires the use of a sterilant, which kills all microbial growth. – Bob Stahurski, President and CEO, Nyco Products Company, Countryside, Illinois

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