In a study published in Scientific Reports, researchers from Germany showed just how germy 14 different used kitchen sponges actually were with more bacteria than typically found in the toilet. I say typical because you know the common saying, “different people, different toilets.”
The team from Justus–Liebig–University Giessen (Massimiliano Cardinale and Sylvia Schnell), German Research Center for Environmental Health (Tillmann Lueders), and Furtwangen University (Dominik Kaiser and Markus Egert) used 454–pyrosequencing of 16S rRNA genes and fluorescence in situ hybridization coupled with confocal laser scanning microscopy (FISH–CLSM) to analyze the bacteria content of used kitchen sponges including those that are regularly “cleaned”. (…) They found not one, not two, but 362 different types of bacteria. And many of these are not just benign, friendly bacteria. Five of the 10 most frequently detected bacteria species had “pathogenic potential.” In other words, they could cause problems and disease in humans, i.e., you. Yes, your kitchen sponge is a huge and shady nightclub for bacteria.
If you have a stinky sponge, then you may want to blame Moraxella osloensis. This stinky bacteria is often responsible for making laundry smell and appeared abundantly in the sponges. Interestingly, the researchers found that boiling or microwaving the sponges could even increase the load of Moraxella osloensis, probably by killing off other better smelling bacteria and allowing the Moraxella more room to reproduce at the bar of the nightclub… so to speak. While Moraxella osloensis is not a common cause of infections in humans, there have been cases.
What should you do then about the stinky nightclub of bacteria that is resting besides your kitchen sink? First, don’t freak out. No matter how lonely you may feel at certain times, you are never alone. Bacteria is everywhere, although they may not be very talkative or like Netflix. Secondly, wash your hands regularly and properly. Third, clean your sponge regularly and properly, such as boiling your sponge, microwaving it on high, or soaking it in bleach for at least a minute. (…) The Academy of Nutrition and Dietetics recommends cleaning your sponge daily. Fourth, replace your sponge frequently, even if it looks OK. You can’t see bacteria but they can see you. While cleaning your sponge regularly properly can help the bacteria count down, you should still replace your sponge regularly. The researchers recommended once a week while others have said about once a month, which is probably more frequent than you currently replace your sponge. Somewhere in this range is probably reasonable, depending on how often you use the sponge, whether you regularly clean the sponge, and what you do with it. Finally, if your sponge smells, just throw it away. Moraxella osloensis stinks.