What kinds of microorganisms can be found in sponges? Well, the five major causes of food-borne illness such as salmonella, E.coli, campylobacter, clostridium perfringens, and staphylococcus are commonly found on sponges. And we wash our dishes and wipe down our counters with these? Ew!
So, what to do? Easy: zap them in the microwave! The heat generated by microwaving a sponge for two minutes kills 99% of the microbes. Please microwave sponges when they are wet, and never microwave them dry; they become fire hazards.