Contact 6 test: How much bacteria is on your mask?

Wearing a mask is part of our daily routine amid the coronavirus. Many of us wear reusable masks. Contact 6 wanted to know what bacteria may be lingering inside our masks and whether it's harmful.

In Milwaukee, our team approached 20 strangers and asked for permission to swab the insides of their masks. Their specimen was tested by Accelerated Clinical Labs.

Many of the people we approached seemed just as interested in what we’d find. Most admitted to wearing their masks multiple times before washing them.

Accelerated Clinical Laboratories has a state contract for coronavirus testing and tested our mask samples for COVID-19. None of the masks tested positive.

Next, the lab ran bacteria tests. Lab Manager Angela Thomm found a number of plates with considerable growth.

"There was a wide range of different types of microbes," said Thomm.

Two of the plates with the most growth came from a couple who told us they’d worn their masks at least 15 times without washing them.

To understand the lab’s results, we turned to Sonia Bardy, a microbiologist at the University of Wisconsin-Milwaukee. Bardy said our plates revealed mostly facial bacteria and some fungus that’s normal, though in some cases, could lead to acne.

"Having bacteria on your skin is great," said Bardy. "It's a good thing, actually. Different people are going to have different levels of bacteria on their skin."

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Our lab test did find bacteria that causes staph infections, which can be a problem if you have a cut on your face but is also common.

Jeana Holt from UWM’s College of Nursing said while your body’s personal bacteria are usually not harmful to you, it should not be exposed to others. That’s one reason masks should not go on kitchen counters.

"That could then transfer it to a different surface," said Bardy.

Holt recommends storing your mask in its own bag, washing your hands after handling it and only touching the mask's ear loops.

"So ideally, when you come in, you're either putting it in a Ziploc bag, paper bag or cleaning it right away," said Bardy.

Holt added you should not wear your mask on both sides. Two people whose masks were tested by Contact 6 told us their masks were reversible.

"We actually could be transferring the virus on the mask to our nose or mouth or eyes," said Holt.

Expert advice is to wear a reusable mask for 24 hours before putting it in the wash. Soap and water or laundry detergent is sufficient. The water can be hot or cold. Using laundry sanitizer is not necessary.