Kitchen sponges are a good metaphor for everything that's wrong in the world. And now, a new study found that instead of trying to clean your dirty sponge, you probably should just throw it in the garbage and set the garbage on fire. The New York Times reports that microwaving a dirty sponge does indeed kill the weak bacteria, but "the strongest, smelliest, and potentially pathogenic bacteria will survive." Oh, and then "they will reproduce and occupy the vacant real estate of the dead." A horrifying but accurate way to put it, according to a new study published last month in Scientific Reports.
In the study, Markus Egert--a microbiologist at the University of Furtwangen in Germany--and his team analyzed 14 used sponges (that, as The New York Times highlights, "may be as dirty as the one sitting in your sink right now”). The scientists found a whopping 362 different species of bacteria inside the sponges, with 82 billion bacteria within just one cubic inch of the sponges on average.
"That's the same density of bacteria you can find in human stool samples," Egert told The Times. "There are probably no other places on [E]arth with such high bacterial densities."
Great! Fantastic! Not disturbing at all! So why exactly are our cleaning instruments the nastiest places in the house? Well, the sponge has what The Times calls "he perfect living conditions" because of all the "warm, wet, and nutrient-rich space for [bacteria] to thrive." And cleaning your dirty sponge won’t help matters whatsoever, according to the study—in fact, it’ll only make the situation even nastier.
When your sponge starts to stink and get nasty, you may want to try disinfecting it, or microwaving it, or throwing it in the dishwasher, but researchers found more dangerous and potentially pathogenic bacteria in sponges that were routinely disinfected. "When people at home try to clean their sponges, they make it worse," Egert said, adding that it may be best to replace your sponge every week.