A new study shows just how dirty your kitchen sponge is.

Researchers in Germany say the average kitchen sponge has more bacteria than a toilet.

The study, which was published in Nature, found the following bacteria in kitchen sponges: E. coli, campylobacter (one of the main causes of diarrheal diseases), Enterobacter cloacae, Klebsiella (which can cause pneumonia), Proteus (which can cause urinary tract infections, salmonella, and staphylococcus.

While studies have found that microwaving or boiling your sponge can reduce bacteria — the findings only appear to work in a lab environment. The new research shows real-world, used kitchen sponges are much more resistant to common cleaning methods.

Researchers recommend replacing your kitchen sponge at least once a week.