The Dos and Don’ts of Clean Kitchen Sponges

It’s one of the germiest spots in the house. 

After thinking for years that a quick stint in the microwave could rid dirty kitchen sponges of germs, a recent study published in Scientific Reports is causing us to rethink everything we thought we knew about sponge safety. According to the German study, regularly sanitizing sponges by popping them in the microwave or boiling them in water doesn’t make them germ-free, and in fact, two types of bacteria were more prominent on the “sanitized” sponges than on unwashed ones. As new research identifies sponges as “microbiological hot spots,” we thought it was a good time for a refresher on the right way to care for sponges. While no kitchen sponge is completely devoid of germs, here are five guidelines to follow.

Do: Replace Sponges Often

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The best way to guarantee a clean kitchen sponge is to replace it as often as possible, rather than attempt to de-germ a used one. How often, you ask? TIME recommends investing in a new sponge every week. Trust us, the extra cost will be worth avoiding the E. coli and salmonella your old sponge may harbor.

Don’t: Microwave or Boil Sponges

As the study in Scientific Reports shows, attempting to sanitize used sponges won’t make them cleaner, and it may even promote the growth of certain types of bacteria. Save the time you used to spend washing sponges and buy a new one instead.

Do: Ditch Smelly Sponges

When your kitchen sponge starts to smell, that’s a sign it’s brewing bacteria. According to the recent study, one type of bacteria, Moraxella osloensis, which survived the sponge’s run in the microwave, is also attributed with making dirty laundry stink, according to a 2012 study.



Don’t: Cross Contaminate

You likely already know not to wash your dishes with the same sponge you use to clean up meat juices, but it’s also a smart idea to designate separate sponges for dishes and countertops. Even if you’re not handling raw meat, raw vegetables have also been implicated in past E. coli and salmonella outbreaks. To prevent spreading this bacteria onto your clean dishes, appoint different sponges for dish, countertop, and raw meat duty. Be careful: don’t store these sponges stacked together or you’ll undo all your efforts. Instead, invest in a clever rack that keeps the “good sponge” and “evil sponge” separated.

Do: Let Them Dry Out

When left soaking wet in the sink or on a countertop, sponges are a breeding ground for bacteria. While wringing out sponges completely and letting them dry in an open area may help slow down the rate of bacteria growth, it won’t prevent it completely. Also consider dishcloths and other quick-drying cleaning tools as alternatives to traditional sponges.