It’s your trusty kitchen sponge that you use for everything. Whether it’s to clean the dishes, wipe down the counters, or scrub your pots and pans. But research has shown that sponges might not be your best tool in the kitchen. In fact, they harbor more bacteria than almost any other kitchen tool.
According to Markus Egert, a microbiologist at Furtwangen University, in Schwarzwald, Germany, used kitchen sponges are colonized by a large diversity of microbes, including bacteria, fungi, and viruses.
“There’s an entire universe of microbes,” says Egert. In all, 54 billion of them per cubic centimeter.
Comparing Your Kitchen Sponges to Feces
Just to provide some context, this would be around the same amount of bacteria that one would find in human fecal samples. So basically, your kitchen sponge might be as dirty as feces.
“The quality of bacteria would be different, but the amount is similar,” says Egert.
In a July 2017 study published in Scientific Reports, Egert and his team found that kitchen sponges were “microbiological hot spots” that “collect and spread bacteria with a probable pathogenic potential.”
Surprisingly, Egert also found that if you tried to clean your sponge, you might make it worse than it was before because the sponges contained higher percentages of potentially pathogenic bacteria that could be more likely to spread disease.
“We think that this is a kind of selection phenomenon that, by cleaning, you select the more resistant bacteria,” says Egert.
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Will the Bacteria on a Kitchen Sponge Make You Sick?
Much of the bacteria found on kitchen sponges came from environmental sources like water, soil, food, or those from the skin’s surface, says Egert. Egert notes that the bacteria they found weren’t known to make people sick, but that doesn’t mean that they don’t exist on sponges and can spread disease.
Trond Møretrø, a microbiologist at Nofima, a leading food research institute in Tromsø, Norway, said that sponges are a haven for bacteria because they sit at room temperature, never dry out, and are covered in food residue. In a September 2022 article he authored in the Journal of Applied Microbiology, his team found that sponges commonly harbor microbes that include more harmless bacteria but also those that can be dangerous, including Salmonella.
“The majority of the bacteria that we found were those that don’t make you sick,” says Møretrø.
Still, dangerous bacteria like Listeria, Salmonella, and E. coli found in kitchen sponges may be a tool for spreading disease. Even if you don’t eat meat, dangerous bacteria can still spread through raw fruits and vegetables.
The Best Way to Clean Your Dishes
According to Møretrø, it’s much better to use a kitchen brush to clean your dishes than it is a kitchen sponge. His January 2021 study, published in the International Journal of Food Microbiology, found that kitchen brushes tended to dry out sooner and “are more hygienic than sponges.”
Kitchen brushes work better because they have a handle that keeps your hands safe from contact with potentially dangerous bacteria. Møretrø added bacteria to both sponges and brushes and found that the bacteria died more rapidly on kitchen brushes than they did on sponges, largely because kitchen brushes dry faster at room temperature than sponges do.
“When the brushes dry off, the bacteria die,” says Møretrø.
You can also increase the temperature of the dish water in the sink so that it’s more likely to kill bacteria if you’re using a brush versus a sponge, because the handle allows you to keep your hands mostly out of the water. If you choose to use a sponge, you should replace it each time, he adds.
So if you’re trying to keep your kitchen free of dangerous bacteria that could cause foodborne disease, a kitchen brush is your best tool.
This article is not offering medical advice and should be used for informational purposes only.
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Article Sources
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Sara Novak is a science journalist based in South Carolina. In addition to writing for Discover, her work appears in Scientific American, Popular Science, New Scientist, Sierra Magazine, Astronomy Magazine, and many more. She graduated with a bachelor’s degree in Journalism from the Grady School of Journalism at the University of Georgia. She’s also a candidate for a master’s degree in science writing from Johns Hopkins University, (expected graduation 2023).
