Microbiomes: Bacteria and fungi multiply in our dishwashers

Microbiomes: Numerous bacteria and fungi frolic in the dishwasher

A recent study by German researchers found that resistant bacteria often lurk in household appliances such as washing machines and dishwashers. But that's not all: An international team of scientists has now found that other microorganisms are also found in dishwashers.

Pathogens in the kitchen

Experts repeatedly point out that more attention should be paid to kitchen hygiene in order to prevent health risks. After all, dangerous bacteria lurk in the kitchen such as Campylobacter and Co. Potential pathogens such as bacteria, viruses or parasites can be found on foods such as eggs, meat or lettuce. Kitchen sponges are also a real spinner. And modern technology does not seem to help much either, because bacteria and fungi frolic in dishwashers, as an international team of researchers has now determined.

Microbiomes in dishwashers

One should actually think that the hot washes in the dishwasher kill the pathogens in them. But far from it.

As researchers in the journal “Applied and Environmental Microbiology” report, numerous microorganisms can be found in it even after the washing process.

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

According to a message, there were bacterial genera such as Pseudomonas, Escherichia and Acinetobacter, which are known to be particularly persistent.

The most common fungal species in these samples were Candida, Cryptococcus and Rhodotorula.

Pathogens can be dangerous for some people

Most of the organisms found are harmless, but some of them, such as Acinetobacter, have already developed dangerous resistance.

A few years ago, a multidrug-resistant strain of Acinetobacter brought the operation of an intensive care unit in a hospital in Enschede (the Netherlands) to a complete standstill.

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

Microorganisms survive even under unfavorable conditions

"The age, the frequency of use and the hardness of the tap water entering the dishwasher had a significant impact on the composition of bacteria and fungi," the researchers write.

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

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

The severe conditions in domestic dishwashers should actually prevent the growth of most microorganisms. However, the investigations showed that such organisms can establish themselves even under unfavorable conditions.

Contamination of the machines could lead to health effects. (ad)

Author and source information

Video: SITXFSA001 Use hygienic practices for food safety. lecture 2020. Ajoy Cena (August 2020).