Microbiomes Massive bacteria and fungi multiply in our dishwashers

Microbiome: The dishwasher is full of bacteria and fungi

German researchers have recently found in an investigation that in home appliances such as washing machines and dishwashers often resistant bacteria lurk. But that's not all: an international team of scientists has now found out that in dishwashers also other microorganisms frolicking.

Pathogens in the kitchen

Experts point out again and again that one should pay more attention to kitchen hygiene in order to prevent health hazards. After all, dangerous bacteria such as Campylobacter and Co. lurk in the kitchen. Potential pathogens such as bacteria, viruses or parasites can be found on foods such as eggs, meat or lettuce. Even kitchen sponges are true germicides. And even the modern technology does not seem to help a great deal, because even in dishwashers bugs and fungi, as an international research team has now found.

A study by an international research team has shown that dishwashers have a large variety of bacteria and fungi even after the wash cycle. (Image: leszekglasner / fotolia.com)

Microbiomes in dishwashers

Actually, one should think that the hot washes in the dishwasher will kill the pathogens inside. But far from it.

As researchers report in the journal "Applied and Environmental Microbiology", there are numerous microorganisms to be found even after the washing process.

The international team led by Prem Krishnan Raghupathi from the University of Copenhagen (Denmark) found in the rubber seals of 24 different household dishwashers a great variety of fungi and bacteria in biofilms.

According to a report, it included bacterial genera such as Pseudomonas, Escherichia and Acinetobacter, which are known to be particularly stubborn.

The most commonly encountered fungal genera in these samples were Candida, Cryptococcus and Rhodotorula.

Pathogens can be dangerous for some people

Although most of the organisms found to be harmless, some of them, such as Acinetobacter have already developed dangerous resistance.

For instance, a multidrug-resistant strain of Acinetobacter almost completely halted the operation of an intensive care unit at a hospital in Enschede, the Netherlands, years ago.

In addition, some of the detected pathogens can be dangerous for people with weakened immune systems.

Microorganisms survive even under unfavorable conditions

"The age, frequency of use and hardness of the incoming tap water from dishwashers had a significant effect on the composition of bacteria and fungi," the researchers write.

The fungus Candida, which was found in all machines, probably settled first on newer devices. Thereafter followed other pathogens.

"The global demand for home appliances such as dishwashers and washing machines is increasing, as well as the number of people with weakened immune systems," said the scientists.

Actually, the severe conditions in household dishwashers should prevent the growth of most microorganisms. However, the studies showed that such organisms can establish well even under unfavorable conditions.

The contamination of the machines could lead to health effects. (Ad)