It’s that every time you use that sponge on a “clean” plate, you’re not cleaning the plate. What’s really living inside that spongeThe German team, led by microbiologists Massimiliano Cardinale and Markus Egert, found 362 different kinds of bacteria inside used kitchen sponges. Why the soap you’re using isn’t helpingMost of us run on the same simple assumption: if I use soap, the sponge is clean. Clemson’s food safety extension says it directly: regular dish soap doesn’t meaningfully cut bacteria on a sponge that’s already dirty. You’re also doing exactly what food safety experts point to as a top way germs spread in a home kitchen.