Does Microwaving Your Kitchen Sponge Really Work?

Some people replace their dish sponges as often as they change their sheets, while others wait until the sponge is crumbling apart before swapping it for a new one. You may not think much about your sponge, perhaps because you use dish soap on it, or because its doesn't seem like a particularly important household item, and if this sounds like you, prepare to be alarmed. 

A study published in the Scientific Reports journal found that sponges carry upwards of 362 different types of bacteria, and hold as many as 45 billion bacteria per square centimeter. The study's author, Markus Egert, a microbiologist at Furtwangen University in Germany, shared with NPR, "That's a very huge number of bacteria, indeed," and he shares, "There's hardly any habitat on Earth where you'll find similar densities of bacteria, except for the human intestinal tract."

The University of Florida agrees that the sponge is a household carrier of bacteria and viruses, specifically those that cause food borne illnesses, but shares there are ways to eliminate those pesky germs.

Research shows that microwaving sponges can eradicate most of the bacteria they hold, including E.coli and Salmonella. The university's professor of environmental engineering, Gabriel Bitton, explains, "Basically, what we find is that we could knock out most bacteria in two minutes ... People often put their sponges and scrubbers in the dishwasher, but if they really want to decontaminate them and not just clean them, they should use the microwave," (via University of Florida)

In the 2006 study, co-authored by Bitton and published in the Journal of Environmental Health, researchers submerged sponges in a treacherous mix of fecal bacteria, E. coli, and bacterial spores, which are difficult to kill. The study found that when the sponges were microwaved for two minutes at full power, 99% of all the germs and bacterial spores were killed. Going a bit further, microwaving the sponges for two more minutes (four minutes total) killed 100% of the bacteria and germs. 

If you want to keep your kitchen sponge around longer than 1-2 weeks, which is the recommended replacement time, make sure you lather it up with dish soap and water and place it in the microwave for two minutes to kill off any nasty viruses and bacteria (per The Healthy).