Sponge germs sponge

Dr. Andrea Bannert has been with since 2013. The doctor of biology and medicine editor initially carried out research in microbiology and is the team's expert on the tiny things: bacteria, viruses, molecules and genes. She also works as a freelancer for Bayerischer Rundfunk and various science magazines and writes fantasy novels and children's stories.

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The kitchen should actually be a hygienic place. But it is precisely there that researchers have identified a paradise for bacteria: the kitchen sponge. Sometimes there are as many germs cavorting in it as in faeces! Hot washing or microwaving the sponge makes things even worse in the long run.

A kitchen sponge has a multitude of small pores - together they form a huge surface. Inside there is a humid climate and leftovers or dirt particles collect everywhere. So ideal living conditions for bacteria.

As many bacteria as in feces

"Sometimes you can find over 50 billion bacteria per cubic centimeter there," says Professor Markus Egert from Furtwangen University. “These are concentrations that are otherwise only found in faecal samples.” The microbiologist led a study in which scientists used a genetic make-up to examine which bacteria live on used kitchen sponges. To do this, they collected 14 sponges from randomly selected private households.

The researchers identified a total of 362 different types of bacteria on the sponge material. And they weren't all harmless. “What surprised us: Five of the ten most common species we found belong to so-called risk group 2,” explains Egert. This means they can potentially cause diseases such as infections. Some of these microorganisms are common environmental and aquatic bacteria, while others typically live on human skin.

Wash out hygiene trap

However, those who want to get rid of the pathogens with the microwave or by washing them out with hot water will not solve the problem. On the contrary: Although this reduces the number of bacteria in the short term, they multiply again. It is precisely the proportion of dangerous microorganisms that then increases. Probably because they are more resilient than their comrades-in-arms.

Those who are healthy will probably put away the bombardment of germs that can emanate from a used kitchen sponge. It can be different for people with a weakened immune system, such as the elderly or the sick. At least in private care, in hospitals or old people's homes, household sponges should therefore be disposed of regularly, the scientists recommend. Incidentally, the researchers were unable to detect any bacteria in newly purchased sponges.

Tags:  skin care Baby Child prevention