When you think about it, it’s not so hard to believe that the sponge is the dirtiest item in your house. Using a sponge to scrub down a cutting board that had recently been coated with raw meat or poultry can contaminate it with dangerous bacteria like salmonella and E. coli. A study conducted by Gerba of 1,000 used kitchen sponges and dish towels found that as many as 10 percent of them contained salmonella, and though soap and water might remove grime and leftover food, this combination doesn’t necessarily kill the bacteria. In fact, water needs to be at least 140 degrees Fahrenheit to be effective at killing germs. Therefore, scrubbing a plate with a dirty sponge is essentially transferring all the bacteria from countertops, cutting boards, floors, tables, and sinks right back onto the dishes.
Fortunately, there are proven ways to effectively clean your sponges. The United States Department of Agriculture tested four different methods and found that either microwaving a sponge for one minute and running it through the dishwasher killed 99.999 percent of bacteria.