Your common household kitchen sponge -- most likely yellow, green and sudsy -- is a bastion of horrible filth. New research contends that microwaving your sponge to kill off the festering bacteria is largely a myth that works only as a stopgap. In order to rid yourself of the literal billions of microbic bacteria proliferating inside the absorbent surface, you have to completely dispose of the sponge on a weekly basis.
This is at least what Markus Egert, a microbiologist at the University of Furtwangen in Germany, told the New York Times. Cutting right through to the muck and mire, Egert says that your sponge is the equivalent of human feces when it comes to microbial density -- a.k.a. the preponderance of germs packed closely together in a small area: “That’s the same density of bacteria you can find in human stool samples," he said. "There are probably no other places on earth with such high bacterial densities," compared to the $1 cleaning tool you use to sanitize your pots and pans.
Egert's harsh words stem for a study he and his team conducted that tested 14 regular household sponges for bacterial content. What they found was a horror-show, or more specifically, 362 different subspecies of bacteria packed tightly in an average sponge. Their findings, published in the journal Scientific Reports, present a cautionary tale for your kitchen sink. Why? It determined that there's about 82 billion bacteria festering within a cubic inch of space on your average sponge.
Yes, bacteria is everywhere -- including your own body -- and your sponge isn't likely to give you an infection, but that doesn't mean it can't. A bacteria called Moraxella osloensis tends to thrive on sponges and on human skin. Although it's largely responsible for the foul stench of your sponge and your dirty gym clothes, it can cause infections in people with weak immune systems, according to the study. So don't eat your sponge, no matter how appetizing the half-eaten remnants of your dinner might look.
Also, zapping your sponge in the microwave or spritzing it with vinegar is a fool's errand. "When people at home try to clean their sponges, they make it worse,” Egert says. In fact, the study found sponges were actually dirtier when they were frequently washed, so good luck cleaning that which cannot be cleaned. The squeeze here is to abandon all hope. Your sponge is awash in muck, and there's nothing you can do about it -- apart from heading to the dollar store to by a new one.