When participants in a study from NSF International (an independent public health organization) swabbed various items in their houses, the kitchen sponge was by far the germiest. In fact, it harbored 150 times more bacteria, mold and yeast than a toothbrush holder. “You pick up bacteria when cleaning, but because you rarely disinfect that sponge between uses, germs multiply,” says Rob Donofrio, M.S., Ph.D., NSF’s director of microbiology. While the majority of germs they found won’t make you sick some, such as Salmonella and E. coli, can cause serious illness. The best way to de-germ your sponge: microwave a wet sponge for two minutes daily and replace it every two weeks.