Infection risk Kitchen sponges are true germicides

Bacteria density as in fecal matter
Flush sponges are used in almost every kitchen, be it to clean dishes and surfaces or to clean up dirt. But beware: The practical cleaning utensils are often anything but hygienic, but just bursting with germs. In a comprehensive study, researchers discovered more than 300 different types of bacteria in used sponges, some of which can even cause illness. The study has now been published in the scientific journal "Scientific Reports".

Scientists examine used kitchen sponges
What's the dirtiest place in the household? Most people probably think of the toilet on this question. But far from it. Because especially many pathogens cavort in the kitchen, where, for example, cutting boards and the refrigerator provide an ideal breeding ground for bacteria. Scientists at Furtwangen University (HFU), Justus Liebig University Gießen and Helmholtz Zentrum München have now investigated in a cooperation project how high the germ load in kitchen sponges is. For the world's first study of this kind, they collected 14 used sponges from households in the Greater Villingen-Schwenningen area and put them under the microscope.

Kitchen sponges are the ideal breeding grounds for bacteria and should therefore be regularly renewed. (Emuck / fotolia.com)

Ideal conditions for germs
The Unappetizing Result: Sponges are often true germs and in some cases even potentially pathogenic agents. "Partially, the bacteria reached densities of more than 5 times 1010 cells per cubic centimeter," explains study leader Dr. Markus Egert according to a message from Furtwangen University. "These are concentrations that are otherwise only found in fecal samples."

According to the experts, the high densities can be explained by the fact that the pathogens in the sponges find ideal living conditions. Because they are mainly made of foam, such as polyurethane, created by the myriad pores, a huge inner surface, which offers the microorganisms plenty of room for propagation. Added to this are the moisture and plenty of nutrients, for example, if spilled food remains or dirt. Were brushed up. Overall, the scientists found 362 different types of bacteria in the samples.

Risk of infection for immunocompromised people
"What surprised us: five of the ten most common species we found belong to the so-called risk group 2, which means they are potentially pathogenic," explains Egert. These included environmental and water bacteria as well as pathogens found on human skin. In persons with weakened defense, such as Therefore, bacteria such as Acinetobacter johnsonii, Moraxella osoloensis and Chryseobacterium hominis could cause an infection.

100 million contaminated sponges
There are around 40 million private households in this country. "If only one or two sponges are present in each of them, their number in Germany amounts to 40 to 80 million," explains study leader Dr. med. Markus Egert according to a message from Furtwangen University. "Institutional facilities are expected to reach more than 100 million in Germany." - 100 million potential germicides, "continued the professor of microbiology.

Cleaning does not help
Of particular concern to researchers is that in sponges that regularly, e. were washed in the microwave or by washing out, significantly more of the potentially pathogenic bacteria were discovered. Experts say cleaning could reduce the number of germs in the short term, but in the rapidly replicating communities, it would seem that the potentially pathogenic bacteria would dominate. The reason for this is probably their higher stress tolerance, the information from the university.

Renew sponges once a week
The scientists recommend not cleaning kitchen sponges, but regularly (about once a week) to dispose of or exchange them with new ones. This is particularly important in places where people live with a weakened immune system, for example in hospitals, old people's homes or private home care. (No)