Dr Michelle Dickinson: nanotechnologist on the new research unveiling that microwaves are full of bacteria

How often do you clean your microwave?

Chances are, it’s not as often as you clean your countertops. Many of us believe that bacteria can’t survive inside a microwave so don’t clean it as often as our other kitchen surfaces, but new research out this week in the journal Frontiers in Microbiology has some startling findings.

Rather than being zapped and killed by the microwaves that heat up your food, the researchers found that many microorganisms can survive the intense radiation and happily live and grow in your microwave.

The researchers swabbed the inside of 30 microwaves found in people’s homes, shared office kitchens and scientific laboratories. They then cultured the samples and sequenced their DNA to identify the microorganisms present.

In total, they identified 101 microbial strains from 747 different genera of bacteria. Many of these microbes are commonly found on human skin, and some of them are known to cause food-borne illnesses.

The study also found that the location of the microwave influenced the types of bacteria present. Unsurprisingly, microwaves in science laboratories had the most diverse bacterial communities, including 'extremophiles' which are microbes that can survive in environments that were once thought not to be able to sustain life such as hydrothermal vents, Antarctica, and even in the stratosphere.

Microwaves aren’t the only household appliances with their own microbiomes. Previous studies have found diverse microbial communities in coffee makers and dishwashers.

The research is a good reminder to clean your microwave regularly - and could help us to find super-bacteria that could help to clean-up environmental disasters through breaking down toxic waste.

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