If we’ve learned anything about kitchen sponges, it’s that they’re usually packed full of mold and bacteria. Unfortunately, it turns out washing them won’t help.
According to a recently published study from the online journal Scientific Reports, cleaning your kitchen sponge by microwaving or boiling it doesn’t significantly reduce bacteria and can even increase it, in certain cases. This is troubling, considering researchers also determined that these sponges are the “biggest reservoirs of active bacteria” in your household, making them even grosser than your toilet.
“Sanitation by boiling or microwave treatment has been shown to significantly reduce the bacterial load of kitchen sponges and can therefore be regarded as a reasonable hygiene measure. However, our data showed that regularly sanitized sponges (as indicated by their users) did not contain less bacteria than uncleaned ones,” the study says.
Researchers also said that “special cleaning” of the sponges resulted in an increase in certain types of bacteria.
“Presumably, resistant bacteria survive the sanitation process and rapidly re–colonize the released niches until reaching a similar abundance as before the treatment,” the study said. “Although further analyses, including controlled sanitation experiments, are needed to substantiate these findings, our data allow careful speculation that a prolonged application of sanitation measures of kitchen sponges is not advisable.”
So instead of trying to save your sponge by cleaning it, researchers suggest simply throwing it out.
“From a long term perspective, sponge sanitation methods appear not sufficient to effectively reduce the bacterial load in kitchen sponges and might even increase the shares of [disease]-related bacteria,” the study concludes. “We therefore rather suggest a regular (and easily affordable) replacement of kitchen sponges, for example, on a weekly basis.”
If you’d rather not feel wasteful by throwing out a sponge every week, we suggest buying something non-porous, like this silicone scrubber, to do your dishes.