Microwaves are home to thriving communities of tiny microbes. Scientists in Spain recently analyzed samples taken from 30 microwaves and identified more than 747 different types of bacteria. Many were extremophiles—microbes that can survive harsh conditions, like being zapped by a microwave! These findings go against the long-held belief that the high-energy radiation emitted by microwaves to heat food will kill off any microorganisms.

But don’t worry—most bacteria are harmless, and some can even be helpful. “Microwaves are as clean (or as dirty) as any other part of the kitchen,” says Manuel Porcar, a microbiologist at the University of Valencia who led the study. Still, it doesn’t hurt to clean your microwave regularly—just like any other part of your home.