For most of us, the thought of sanitizing our kitchen sponges never crossed our minds. And that’s probably a good thing.
Scientists from Germany recently reported what they found living inside kitchen sponges. They took samples from 14 used kitchen sponges and extracted DNA. What they found was an astounding 54 billion bacteria cells per cubic centimeter of sponge.
While most of the bacteria found are not harmful to humans, the researchers did find bacteria such as E. coli, and Klebsiella and Moraxella species in the sponges. Kitchen sponges also have the second highest amount of coliform bacteria (bacteria that serve as indicators for fecal contamination) in the whole house. When we thinking about fecal bacteria, the toilet is first to pop into mind. So are coliform bacteria found in the highest quantity in the bathroom? No. It’s actually sink drain traps.
The scientists also investigated whether sanitizing sponges is worth the effort. Surprisingly, they found that boiling or microwaving sponges doesn’t help at all. Bacterial numbers don’t seem to change before and after sanitization and to make matters worse, sanitization efforts actually backfire: pathogen-related species make up a higher proportion of total bacteria after sanitation. This happens possibly because sanitizing the sponges kills some bacteria and that pathogenic bacteria, which may be more likely to resist sanitization efforts, take over.
The solution to this problem? The researchers recommend replacing the sponge every week. However, the scientists who performed the study also pointed out that they were not aware of any incidence of infections with sponge bacteria as the culprit.
As for me, I think I’m going to clean some dishes with my old kitchen sponge right now.