Your Sponge Is the Kitchen's Dirtiest Item
Studies sampling kitchen sponges have consistently found them harboring more bacteria per square inch than almost anything else in the house, including the toilet, because they're perpetually damp and full of food particles. Microwaving a wet sponge for 1-2 minutes or running it through a dishwasher cycle kills most of that, but replacing sponges every 1-2 weeks is the more reliable fix.
Sources & methodology: These tips draw on established food-science references —
Harold McGee's food-science writing, America's Test Kitchen /
Cook's Illustrated testing, Serious Eats'
technique reporting, USDA food safety guidance,
and peer-reviewed food-safety research (including UC Davis
cutting-board studies) — not reworded recipe-blog consensus.