Bacteria density as in faeces
Sponges are used in almost every kitchen, be it to clean dishes and surfaces or to wipe up dirt. But be careful: The practical cleaning utensils are often anything but hygienic, but are brimming with germs. In a comprehensive study, researchers discovered more than 300 different types of bacteria in used sponges, some of which can even make you sick. The study has now been published in the scientific reports.
Scientists examine used kitchen sponges
What's the dirtiest place in the household? Most people probably think of the toilet when asked this question. But far from it. Because a particularly large number of pathogens frolic in the kitchen, where cutting boards and the refrigerator, for example, provide an ideal breeding ground for bacteria. Scientists from the Furtwangen University (HFU), the Justus Liebig University Gießen and the Helmholtz Zentrum München have now investigated in a cooperation project how high the bacterial load in kitchen sponges is. For the world's first study of this kind, they collected 14 used sponges from households in the Villingen-Schwenningen area and examined them closely.
Ideal conditions for germs
The unsavory result: sponges are often a real spinner and in some cases even contain potentially pathogenic agents. "In some cases, the bacteria reached densities of more than 5 x 1010 cells per cubic centimeter," explains study leader Dr. Markus Egert according to a message from Furtwangen University. "These are concentrations that can only be found in faecal samples."
According to the experts, the high densities can be explained by the fact that the pathogens find ideal living conditions in the sponges. Since they are predominantly made of foam, such as polyurethane, the innumerable pores create a huge inner surface, which offers the microorganisms a lot of room for reproduction. Added to this are the moisture and abundant nutrients, for example when using the sponge for food residues or dirt. Wiped up. In total, the scientists found 362 different types of bacteria in the samples.
Risk of infection for weakened 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, but also pathogens that occur on human skin. For people with weakened defense, such as old and sick people, bacteria like 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 there are only one or two kitchen sponges in each of them, the number in Germany will be between 40 and 80 million," explains study leader Dr. "With institutional institutions, there are probably more than 100 million in Germany." - 100 million potential germinators, "continued the professor of microbiology.
Cleaning doesn't do anything
According to the researchers, it is particularly worrying that in the sponges that are used regularly, e.g. in the microwave or by washing, significantly more of the potentially pathogenic bacteria were discovered. The experts' assumption: Although cleaning could reduce the number of germs in the short term, the potentially pathogenic bacteria would then obviously dominate in the rapidly growing communities. The reason for this is probably their higher stress tolerance, according to the university.
Renew sponges once a week
The scientists recommend not to clean kitchen sponges, but to dispose of them regularly (about once a week) or replace them with new ones. This is particularly important in places where people with a weakened immune system live, for example in hospitals, old people's homes or in private care at home. (No)