Just How Clean is Your Kitchen Sponge?

Just How Clean is Your Kitchen Sponge?
Are there more germs than you think lurking in your dish sponge?

What common household item has around 362 different species of bacteria residing inside it? You’ve probably already guessed from the title it’s your average, everyday kitchen sponge, but did you know killing those little critters takes more than a few minutes in a microwave, as per some of the latest “kitchen hacks” advice?

It seems that nuking (microwaving) used sponges does kill some of the bacteria, but not the worst ones, according to a study published in Scientific Reports and titled “Microbiome analysis and confocal microscopy of used kitchen sponges reveal massive colonization.”1The study explains something previous research has missed; namely, that a used kitchen sponge generally carries not just a lot of germs, but a lot of different species of germs. As The New York Times asserts:

“It may nuke the weak ones, but the strongest, smelliest and potentially pathogenic bacteria will survive. Then, they will reproduce and occupy the vacant real estate of the dead. And your sponge will just be stinkier and nastier and you may come to regret having not just tossed it.”2

There are bacteria, then there are pathogens, which Science Daily describes as “a biological agent that causes disease or illness.”3

Kitchen Sponge Microbiome: Yikes

In the study, a research team led by Markus Egert, a microbiologist at the University of Furtwangen in Germany, examined the DNA and RNA in samples from 14 used sponges and found 362 bacteria species. Besides the surprise of that, the researchers were flummoxed by the density of all those microbes jammed into such a tiny space. In total, about 82 billion bacteria inhabited a single cubic inch of sponge.

The scientists used a few different tools to detect the different bacteria types, including fluorescence and laser microscopy. Not all the sponges were old or loaded with food particles, and some had been “cleaned.”

With what we know about bacteria, it’s no surprise that they love hanging out in used sponges, what with all the raw chicken juice, seafood and other random food bits, not to mention whatever germs might be on food packaging handled by people who haven’t washed their hands. Such cross-contamination is a leading cause of foodborne disease.

And people often use sponges to wipe down the kitchen sink, refrigerators, cutting boards, can openers, garbage pails and countertops, the last of which is the recipient of everything from grocery bags to kids’ toys to your cellphone. These items may have come into previous contact with your bathroom sink, the floor of your car and your neighbor kid’s mouth.

Part of the problem with sponges in particular is that they’re generally held under a faucet of warm to hot running water, which simply jump-starts additional bacteria, as the moisture and warmth creates the perfect living environment for them. One of the worst is a particularly prolific microbe called Moraxella osloensis, which lives on human skin and can cause infections in people with weak immune systems.

That nasty dirty-laundry smell is often caused by these bacteria, as is the mildew-meets-microbe odor you may smell the moment you walk toward your kitchen sink. Other dirty-sponge bacteria generally include E. coli, campylobacter (which is the main cause of many types of diarrhea), Enterobacter cloacae, Klebsiella (which can cause pneumonia), Proteus (a common cause of urinary tract infections), salmonella and staphylococcus, Fox 8 Cleveland4 reports.

Your Kitchen Sponge Contains More Germs Than Your Toilet

As it turned out, the 14 sponges the scientists used in their research ended up containing more bacteria than your average toilet. In fact, a Forbes article asks, “Do you wash your dishes in the toilet?” Of course, not all toilets are the same, just as not all sponges are the same.

It has everything to do with how long they’ve been used, and by whom and for what. But here’s the kicker: Egert equated the number of bacteria with that of human stool samples and commented, “There are probably no other places on earth with such high bacterial densities.”5

Back to equating your kitchen sponge’s dirty innards with that of your toilet’s, it may seem a little harsh since you don’t (presumably) actually poop in your kitchen sink. Further studies show that many people don’t wash their hands correctly, or as often as they think they do. In addition, your kitchen, being the hub of the house, is the room most frequented by friends and family, and along with them, their germs.

Read the rest of this story on Mercola.com.