Paradise for Germs: How Often Should You Change Your Dishwashing Sponges?

In the kitchen, dishwashing sponges are one of the biggest sources of germs. To protect yourself from illness and ensure your dishes are cleaned hygienically, it's important to replace your dishwashing sponge regularly.

Be honest: how often do you change the sponges in your kitchen? If you only switch them out every two weeks—or even less frequently—it's time to reconsider your routine. Ideally, you should be replacing them every week.

This frequent replacement might seem wasteful, especially if you're using traditional plastic sponges. Instead, consider using reusable options like cotton cloths, which can be washed at 90°C after each use, or microfiber cloths, which can be washed at 40°C. These alternatives help cut down on waste and are better for the environment.

Why Are Sponges So Full of Germs?

Dishwashing sponges are notorious breeding grounds for bacteria. A study by Furtwangen University, Justus Liebig University Giessen, and the Helmholtz Center in Munich found that kitchen sponges can harbor up to 362 different types of bacteria.

Most dish sponges are made of foam, which has a porous surface area that makes an ideal environment for bacteria to thrive. In fact, in some cases, the density of bacteria found in sponges was more than 50 billion cells per cubic centimeter. "These are concentrations that are normally only found in fecal samples," says study leader Markus Egert.

What Types of Germs Live in Your Sponge?

According to Egert, about half of the most common bacteria found in sponges belong to "risk group 2," meaning they have the potential to cause disease. This is especially concerning for people with weakened immune systems. Many of the bacteria found are environmental and water-borne, but some are typical of human skin as well.

The good news? Harmful bacteria like fecal bacteria and diarrhea-causing pathogens were barely detected in the study. But this small relief doesn't mean your sponge is safe to use for too long.

Can You Clean Your Sponges Instead?

Replacing sponges weekly can feel wasteful, and you might be tempted to clean them instead by boiling them or microwaving them. However, these methods aren't as effective as you might think. Although the number of bacteria may initially decrease, they can quickly multiply again, often with even greater resistance to stress.

Unused sponges, on the other hand, don't start out full of bacteria. This is why it's crucial to replace your sponges weekly and store them in a dry place after each use. By changing your sponges regularly and opting for reusable options, you can keep your kitchen more hygienic and reduce your environmental footprint.