The sponge attracts bacteria by offering perfect living conditions. That popular kitchen trick of microwaving the sponge may in fact be doing more harm than good, as it turns out.
Stop. Drop the sponge and step away from the microwave.
That squishy cleaning apparatus is a microscopic universe, teeming with countless bacteria. Some people may think that microwaving a sponge kills its tiny residents, but they are only partly right. 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 not just tossing it, suggests a study published last month in Scientific Reports.
Bacteria are everywhere, so it’s no surprise that a kitchen sponge would be full of them. But previous research had underestimated a sponge’s quantity and range of bacteria. By looking at the DNA and RNA in samples from 14 used sponges that may be as dirty as the one sitting in your sink right now, Markus Egert, a microbiologist at the University of Furtwangen in Germany, and his team identified 362 different species of bacteria living within them. The scientists were surprised to find how densely microbes occupied such close quarters: About 82 billion bacteria were living in just a cubic inch.
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“That’s the same density of bacteria you can find in human stool samples,” Egert said. “There are probably no other places on Earth with such high bacterial densities.”
The sponge attracts bacteria — which arrive via food, the skin or other surfaces — with the perfect living conditions. There is lots of warm, wet and nutrient-rich space for them to thrive.
Among those taking advantage of these amenities, the scientists found, was a microbe called Moraxella osloensis. It is widespread in nature and lives on the human skin. It can cause infections in people with weak immune systems, although the risk posed by the bacteria found in sponges is hard to assess.
Moraxella osloensis is primarily responsible for the stench of dirty laundry, and it may also be the reason your sponge eventually emits a funky odor.
The odor is a compound produced by the bacterium’s metabolism. It eats fat. It excretes fat. And that fatty excrement stinks.
The thrifty may try to clean a sponge that starts to stink,…