If you haven’t sanitized your microwave in a while, it might be time to do so soon: A new study reveals that these kitchen appliances may harbor some of the most resistant microbes ever discovered.
After studying 30 microwaves, the researchers found that the appliances harbored nearly 750 species of bacteria, including some that you don’t want on your food or fingers.
“Some genera found in domestic microwave ovens include Klebsiella, Enterococcus and Aeromonas“Microwaves can pose a risk to human health,” said Daniel Trent, a Darwin Bioprospecting Excellence SL research associate who worked on the study, “but it’s important to note that the microbial communities found on microwaves are not unique or riskier than other common kitchen surfaces.”
KlebsiellaFor example, it is a bacteria normally found in human waste that can cause pneumonia and blood infections in humans and is “increasingly resistant to antibiotics,” according to the Centers for Disease Control and Prevention. Enterococcus and Aeromonas is of similar concern.
Microwaves use radiation to heat food, so it may seem counterintuitive that anything could survive in a microwave. Microwaves are a type of non-ionizing radiation, which means they don’t have the energy to change cells or atoms, and the levels produced by kitchen microwaves are not considered dangerous to humans. According to the FDA, microorganisms are killed when food is microwaved for the appropriate amount of time, but this is due to the heat produced, not the radiation itself.
Not all microwaves harbor the same types of microbiomes — rather, they pick up on some of the microscopic features of their surroundings — and the study found that microwaves in shared spaces and private kitchens harbor a different, less diverse range of bacteria than those in the lab.
“Our results reveal that domestic microwaves harbor a more ‘humanized’ microbiome, similar to kitchen surfaces, while laboratory microwaves harbor bacteria that are more resistant to radiation,” Trent said.
The microbiome in a lab microwave is different from that in a home microwave, but similar to that in a solar panel, and the researchers theorize that conditions in both environments, such as the presence of electromagnetic waves and constant changes in heat, allow only the hardiest bacterial species to survive.
If all of this is putting you off microwaving that frozen chicken pot pie for dinner, fear not: Torrent recommends regularly cleaning up the germ farms in your own kitchen with diluted bleach or disinfectant spray, and doing a quick cleanup of any stains to prevent bacterial growth.