Researchers have discovered radiation-resistant microbes living inside microwave ovens, but the worrying thing is that many strains could be deadly to humans.
“Some strains found in household microwave ovens, such as Klebsiella, Enterococcus and Enterobacteriaceae, may pose a risk to human health,” said Daniel Torrent, one of the study’s authors.
Previous studies have found microbes living in a range of exotic habitats, including marine oil spills, abandoned industrial areas, and even inside the International Space Station. But until now, it was unclear what germs could be found inside microwave ovens.
In the study, conducted by Darwin Bioprospecting Excellence SL, a startup based in Paterna, Spain, the team took microbe samples from inside 30 microwave ovens, 10 from individual home kitchens, 10 from shared home spaces such as cafeterias, and 10 from science laboratories.
Analysis of the samples revealed 747 different genera of microbes within 25 bacterial phyla. However, these strains varied greatly between sites.
“Home microwaves have a more ‘human’ microbiome, similar to kitchen surfaces, while laboratory microwaves have more radiation-resistant bacteria,” Torrent said.
Within the kitchens of individual homes, the main genera of microbes were Acinetobacter, Bhargavaea, Brevibacterium, Brevundimonas, Dermacoccus, Klebsiella, Pantoea, Pseudoxanthomonas and Rhizobium.
Meanwhile, Arthrobacter, Enterobacter, Janibacter, Methylobacterium, Neobacillus, Nocardioides, Novosphingobium, Paenibacillus, Peribacillus, Planococcus, Rothia, Sporosarcina and Terribacillus were found only in household microwave ovens.
Alarmingly, many of these microbes (Klebsiella, Enterococcus, and Enterobacter) can be dangerous to humans.
Klebsiella species can cause a range of healthcare-associated infections, including pneumonia, bloodstream infections, infections of wounds or surgical sites, and meningitis.
On the other hand, Enterococcus has the potential to cause a range of diseases including urinary tract infections, bloodstream infections, and wound infections.
Finally, invasive bacteria (Aeromonas) have been linked to gastrointestinal infections, kidney disease, cellulitis, and meningitis.
Based on the findings, the researchers urge people to make sure they clean their microwaves regularly.
“We recommend regularly disinfecting microwaves with a diluted bleach solution or commercially available disinfectant spray,” Torrent said. “In addition, it is important to wipe the interior surfaces with a damp cloth after each use to immediately remove any residue to prevent bacterial growth.”