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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Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudgin
from News Talks.

Speaker 2 (00:11):
EDB and doctor Michel Dickinson. Nana Girl is with us
with her science study of the week.

Speaker 3 (00:17):
Good morning, Good morning this.

Speaker 2 (00:19):
Did I did pause when I read, So let me
ask you a questions.

Speaker 3 (00:26):
You obviously clean your kitchen coaruacters multiple times a day,
right you wipe them down? Do you clean the inside
of your microwave with as much gusta?

Speaker 2 (00:33):
Not as often, but actually more than I probably would
normally because my kids always blowing things up in there,
not covering them. Yeah, there is butter going. My daughter's
a baker. It's always softened butter going everywhere and things
like that. So I do do it a little bit
more than I thought I would, but probably not.

Speaker 3 (00:51):
So this Sunday I thought we might all go clean
our microwaves Sunday chores. And I love this little study
because it was really interesting. So, you know, many people
I've met, including many students because I've worked at universities,
I've met students, have gone, need to clean my microwave
because it kills everything anyway, so it'll be fine. Sadly,

(01:12):
that is not true. So the General Frontiers in Microbiology.
It's a lovely open source paper too, if you want
to spend your Sunday afternoon reading all about bugs. Looked
at what actually is in our microwaves and whether or
not microwaves nuke them and they all die, or whether
or not they're happily living in there around your food.

(01:32):
And so they took thirty different microwaves and they swabbed them. Now,
the microwaves were in different places. Some of them were
in your home, some of them were in shared offices,
which you know you never trust to shared office microwave,
and some of them were in science labs. And then
they cultured sample secrets of DNA unidentified the microorganisms, and
they found horrifically one hundred and one microbial strains from

(01:56):
seven hundred and forty seven different genre of bacteria. And
some of those are not good for you. So you
were like, oh, how harmful can they be? Because why
do we put things on our microwave or we put
them in to heat them up, and we know if
they're heating them up, we know that they inactivate bad
bacteria like Ecoli, Samonila, Listeria. That's good because that's why

(02:17):
we're cooking our food to get rid of those bugs.
But they also found that there are some other bugs
in there that are quite happy being zet and being
heated up and living on and some of those do
actually called course food borne illnesses. So not great news. First,
and the reason that they can do that is some
of these bacteria are amazing at living in what they

(02:40):
call extreme environments. They found them, you know, in Antarctica.
They found them on those you know, the heat vents
down in the ocean, like they're really hot places. And
because they have a special type of heat shock protein
that can help to protect them. And they also have
antiox and enzymes, which means that even if they get
zept it doesn't actually kill them. So these bacteria are amazing.
They have efficient DNA repair mechanisms and you go, oh,

(03:04):
but there are also many of them antibotic resistant, right,
so they're not great. They're living in your microwave. You
probably didn't think that they were there. So basically the
conclusion of this is clean your microwave. More often people
aren't doing it. They were like, people just aren't doing
it enough because the assumption is that it's killing the bugs.

(03:24):
It is not killing all of the bugs. There are
horrific bugs in there. But the great thing about this
study is they said, well, hold on, we found all
of these specteria.

Speaker 2 (03:32):
Can we learn anything from this?

Speaker 3 (03:33):
What should we do? And they said, a lot of
these bacteria might be really useful if we ever had
a toxic waste outbreak. So contamination, get them in there.
Get them in there to eat up all the contaminated
waste because they're great extreme conditions. So yes, silver lining
is like this, can use it. Unsilver lining is Get
a cloth, get some detergent, get some spray and wipe

(03:56):
and go clean inside your microwave because if you're not
doing it as often as you do your cantatops, you're
probably not doing it as often as you should.

Speaker 2 (04:03):
Can we excess the study?

Speaker 3 (04:04):
Yeah, Frontiers in Microvirel year. It was out this week.
It's open source. Go have a read.

Speaker 2 (04:08):
Thank you so much, Michelle.

Speaker 1 (04:11):
For more from the Sunday session with Francesca Rudkin, listen
live to News Talks it Be from nine am Sunday,
or follow the podcast on iHeartRadio.