Latest Trustworthy News from Dr. Mercola - delivered straight to your inbox!
Get 20% Off on Earth Day Sale Get 20% Off on Earth Day Sale

Cleaning a Dirty Sponge Only Helps Its Worst Bacteria, Study Says

  • August 07, 2017

A popular method of cleaning kitchen sponges is not the route you want to go when they get too dirty to use, researchers say. According to The New York Times, a new study shows that microwaving sponges doesn’t kill all the bacteria on them but, rather, allows the strongest bacteria to survive and grow. What’s more, the same bacteria that cause your sponge to emit a foul odor can infect human skin. Other methods of “cleaning” sponges, such as dousing them with vinegar or throwing them in the dishwasher, don’t work either.

Although I’ve noted in the past that microwaves may be good for sanitizing your underwear after you wash them, I can think of no other better reason to simply discard a dirty kitchen sponge than this one, especially since past studies have demonstrated that microwaves have a poor track record for killing bacteria that may be responsible for food poisoning. Why would you want to continue to wash dishes with something that could make you sick?

That’s one reason Philip Tierno, professor of microbiology and pathology at New York University School of Medicine, says water temperatures need to be at least 140 degrees F to kill bacteria and germs living on your clothing (most automatic dishwashers are set at 120). The truth is bacteria are very resilient, even to heat and microwaves.

There is hope, though: According to a new proof-of-principle study, blue light can selectively eliminate infections caused by Pseudomonas aeruginosa, a common bacterium that can infect humans. Blue light therapy has also been shown effective against MRSA and other resistant bugs. It’s even been suggested that blue light treatment might one day replace antibiotics. In the meantime, though, I suggest just tossing that dirty sponge.