A kitchen sponge contains more bacteria than a Petri dish


DURHAM, NC (StudyFinds.org) — Germaphobes beware, it might be time to ditch the kitchen sponge for good. A new study by researchers at Duke University has found that the average kitchen sponge is teeming with more bacterial species than a laboratory Petri dish.

In fact, no matter how many times you replace your sponge, you will still encounter the same problem. The new findings show that it’s not the dirt, but rather the structure of the sponge that makes it a friendly place for microbes to live.

Similar to humans, some bacterial species like to live with their fellows, while others prefer to live alone. In the new study, researchers found that bacterial species that prefer a “mixed housing environment” were more likely to live in your kitchen sponge.

“It turns out that a sponge is a very simple way to implement multi-level portioning to improve the whole microbial community,” Lingchong You, a professor of biomedical engineering at Duke, said in an academic statement. “Maybe that’s why it’s such a dirty thing – the structure of a sponge just makes a perfect home for germs.”

The findings could help industries that use bacteria to clean up pollution or produce commercial products consider the ideal structural habitat for microbes.

Sponges give bacteria plenty of room to thrive

The researchers identified and tracked the population growth of 80 different strains of E. coli in several growth plates in the laboratory. The plates offered multiple options for the bacteria to live, from six large wells to 1,536 small wells.

The large pits mimicked environments where microbial species can mix and live with other species. The small wells mimicked the spaces of bacterial species that prefer a solitary existence.

“The small portions really hurt species that depend on interactions with other species to survive, while the large portions eliminated members that suffer from these interactions (solitaries),” he adds. “But intermediate portioning allowed for maximum diversity of survivors in the microbial community.”

The findings suggest that structural environments with large spaces between them could help microbes thrive. When testing with a kitchen sponge, the team found that it contained even more microbes than any other lab equipment tested.

The study is published in the journal Nature Chemistry Biology.


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