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Label Claims–Disinfectant Dwell Time

Recently I had a question sent to me: In watching your video clip in which you describe manufacturer recommended 10 min. dwell times as being unrealistic, it seems that you are also saying they are unnecessary. Have you discussed this with the Joint Comission who holds accredited facilities to this standard?
My reply went like this: Yes, if a disinfectant is applied with a cloth, wrung out of a bucket, to a surface, that surface might remain wet for 2.5-3 minutes. The CDC asserts that if a surface remains wet for a minimum of 2 minutes, that length of time is sufficient for the disinfectant to work as a poison to microbes (per label claims). The difference between the “real world” and the lab where these dwell times are established, is that in the real world, there is a physical removal of soil along with the mechanical friction that wiping provides (i.e., good old fashioned “elbow grease”).
William Rutala, Univ. of N.C., states that a 6 log reduction happens in the initial 60 seconds the disinfectant is applied to the surface with a rubbing action. After that first 60 seconds, the log reduction plateaus through 10 minutes. There are at least 14 scientific studies proving the same thing that Rutala discovered.
If a surface dries in 2.5-3 minutes, that means that the same surface would have to be re-wetted 4 additional applications in order to provide the “per label” 10-minute contact time. That doesn’t happen in the real world.

And, in 15 scientific studies, that doesn’t need to happen in order to reach sufficient kill of labeled microbes.  When TJC surveyed us last Fall, this was never brought up. I had prepared my housekeepers and the hospital staff by instructing them to pick up the container of disinfectant wipes or the bottle of disinfectant and point to the label and state, “It says right here, 10 minutes (or whatever the particular label states for a dwell time)”.
That tells the surveyor that the employees know the correct dwell time. But, if the surveyor chooses to observe the housekeeper or member of the nursing staff wiping high touch surfaces and put a stop watch to the dwell time, we might have had an open discussion about the world of AST labs, the AOAC standards and the real world of cleaning and disinfection.

Just one other caveat…Legally speaking, if a person, or a facility, chooses to use a disinfectant “OFF Label” (i.e., in a manner inconsistent with the EPA-registration) and an untoward event should occur, you are (in legal terms), on the hook. 
I explain this in the 3-part (not 4-part) series of articles titled: “Disinfectants: What’s in Your Bucket?” You can find the series on my website: darrelhicks.com
darrelhicks.com
I hope this helps you understand the world of Housekeeping and the challenges we face in the battle against HAI’s and cross-transmission.
If not, let me know what else I can provide you with.



About Darrel Hicks

J. Darrel Hicks, B.A., is the author of Wiley Publishing's "Infection Prevention For Dummies", and is nationally recognized as one of the top experts in infection control. Darrel Hicks is also the Past President of the IEHA and is an active member in AHE where he holds the designation of CHESP. View all posts by Darrel Hicks

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