Dwell Time

What it is

Dwell time, also called contact time, is how long a disinfectant has to stay wet on a surface to kill the germs listed on its label. It's often somewhere between one and ten minutes, depending on the product and the germ. If you spray and wipe it straight off, you've cleaned the surface, but you haven't disinfected it.

Why it matters

Most people use disinfectant like an ordinary spray cleaner. That's fine for everyday cleaning, but when you really need to kill germs, like during a stomach bug, after raw chicken, or in a shared washroom, the contact time is what makes it work.

How to get it right

1. Clean off visible dirt first. Disinfectants don't work well through grime.
2. Check the label for the contact time, and in Canada, a DIN (Drug Identification Number).
3. Spray enough that the surface stays visibly wet for that whole time. Spray again if it starts to dry.
4. Wipe, and rinse food-contact surfaces afterwards if the label says to.

Related

• High-touch surface cleaning
• When you really need to disinfect
• Cleaning tools & methods

Source

National Pesticide Information Center: Antimicrobials fact sheet (Oregon State University and the U.S. EPA).