Perhaps you’ve already seen the kitchen hack on Pinterest or some listicles: clean your kitchen sponge by putting it in a microwave to kill the bacteria. They also recommend the method for makeup sponges, too.

However, this study published in Nature Scientific Reports in July conducted by researchers in Germany suggests that we should just throw this household item away instead of disinfecting it. While microwaving (or boiling or dredging in vinegar) may exterminate these microorganisms, it will only hit the weak; the strongest and pathogenic bacteria will survive, reproduce, and then occupy the spaces of the deceased.

nolisoli sponge — *Consider replacing your kitchen sponge weekly instead of trying to disinfect them.*

In fact, the study finds out that microbes Chryseobacterium hominis and Moraxella osloensis “showed significantly greater proportions in regularly sanitized sponges.” Aside from bringing diseases, Moraxella is also responsible for making your laundry stinky and may be doing the same to the sponge. The researchers thus concluded that sponge sanitation methods are not enough to effectively kill bacteria in our porous cleaning aids.

Sponge has the perfect living conditions for bacteria—they’re wet, warm, and nutrient-rich. In a previous research by microbiologist Markus Egert and his team at the University of Furtwangen in Germany, 362 different species of bacteria were found living in 14 used sponges they examined. And they’ve discovered that about 82 billion bacteria were living in just a cubic inch of space.

“That’s the same density of bacteria you can find in human stool samples,” Dr. Egert said. “There are probably no other places on earth with such high bacterial densities.”

Your sponges have fulfilled their duty. They’ve helped you remove gunk on your plates and other surfaces. Now they’re gross and you should just replace it with a new one weekly, like what the study recommends.

“We therefore rather suggest a regular (and easily affordable) replacement of kitchen sponges, for example, on a weekly basis.”

Header image courtesy of Pixabay.com