You might think the radiation generated inside your microwave oven kills any bacteria within its stainless steel walls. You'd be wrong though.
Microbiologists at the University of Valencia took swab samples from inside more than two dozen microwaves located in homes, offices, and even in chemistry labs. Next, they cultured the samples in Petri dishes where more than 100 different strains of bacteria grew.
"A microwave is not a pure, pristine place," said researcher Manuel Porcar.
Finally, they sequenced the organisms' DNA.
From Nature:
The dominant ones belonged to the Bacillus, Micrococcus and Staphylococcus genera, which commonly live on human skin and surfaces that people frequently touch. Human-skin bacteria were present in all three types of microwave oven, but were more abundant in the household and shared-use appliances. A few bacteria types associated with food-borne illnesses, including Klebsiella and Brevundimonas, also grew in some of the cultures from household microwaves.
The team suggests that the extremophile strains they found in the microwave ovens might have been 'selected' evolutionarily by surviving repeated rounds of radiation, and could have biotechnological applications, such as in the bioremediation of toxic waste.
Porcar's advice? Clean your microwave regularly just as you (hopefully) do other surfaces in your kitchen.
Previously:
• Makita announces battery-powered microwave oven
• Old microwave oven deemed superior
