The pandemic had us all cleaning more, spraying Lysol, and wiping down all high-touch surfaces with germ-killing wipes. But cleaning experts say we have probably been doing it all wrong.
Lightly spraying a surface and then quickly wiping it off doesn’t kill the germs like you think it would. In fact, you should wait as long as 30 seconds to four minutes before wiping off a surface. Some labels even recommend waiting 10 minutes and pre-cleaning a surface before using a disinfectant.
What disease scientists and microbiologists have to say.
To truly sanitize a surface, you need to slow down. “The longer you can let it be in contact, the better,” says Dr. Andrew Janowski, professor of pediatric infection diseases at Washington University School of Medicine. “At home, I wait roughly a minute if I’m applying a spray product then wiping.”
It is essential that you read the labels of your cleaning products regarding exposure time and what types of germs they kill. Some will sanitize, meaning they may take care of most bacteria but won’t kill viruses. Disinfectants can inactivate and destroy bacteria and viruses, but not all – only those specified on the labels.
Here are some of the label directions for three commonly used cleaners:
Clorox Bleach – five minutes of contact time
Clorox Clean-Up – 30 seconds
Clorox Anywhere Hard Surface – 2 minutes (bacteria, not viruses)
Clorox Disinfecting Wipes – 4 minutes
Lysol Branded Wipes – Lavender: 10 minutes, Lemon Scent: 4 minutes
These exposure times don’t indicate how long you must keep wiping a surface. They refer, instead, to how long you need to wait for the product to dry before using it again. So don’t panic believing you need to wipe for 10 minutes with your lavender Lysol wipe. Simply wipe, walk away, and let the cleaner do what it needs to without “interference.”
Even if the surface you’ve cleaned dries before the designated label time, researchers have determined that they work even if a few seconds shy.
Why So Many Different Contact Times?
Every cleaning product undergoes a stringent testing process required by the Environmental Protection Agency. The tests involve a high concentration of germs – 100,000 organisms per centimeter (far higher than what is typically found in an average home), and the time determined on how effective each cleaner is in reducing the count. For reference, most homes will see less than 100 organisms per square centimeter on most surfaces, so while contact time based on extreme conditions may seem excessive when it comes to germs, better safe than sorry.
When someone in the house gets a virus or germ, organism contamination can reach very high levels. Nasty viruses like norovirus can cause illness in tiny amounts and can be difficult to remove from every surface in the house, so following label guidelines on exposure time is even more important when dealing directly with a known contagion.
Worth Noting: Some bacteria, such as Staph and Strep, are much harder to kill than viruses. Label recommended times are geared toward eliminating the bacteria with killing the viruses as a bonus.
Why Clean Before Disinfecting?
If you have crumbs, dust, dirt, dander, or spilled food on a surface before you disinfect, you won’t be able to reach all of the bacteria unless you clean off surfaces first. Even if a product claims to clean and disinfect, the label will likely advise you to clean heavily soiled surfaces first.
Sources: New York Times, EPA. Get Biom