How Often Should You Wash Your Coffee Mug?

Not every bacterium is an enemy, but illness-causing germs are out there -- and some love your coffee cup. Learn how often research indicates you should wash that reusable cup in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff Lauren vog Obam Here. People love their coffee,
but most don't extend their profound affection to its trusty receptacle,
the coffee cup. Office workers are often guilty of such neglect,
merely rinsing and reusing their mug day after day, or worse,

(00:23):
just dumping out the old coffee and filling their cup
up with new brew. While it seems that the mug
would be just fine with such treatment, after all, hot
water kills germs and you're the only person who uses
your mug, thank you very much, the truth is perhaps
more eye opening than the beverages inherent caffeine. A mostly
empty mug, left to its own devices, can quickly grow

(00:45):
its own microbiome. Of course, most bacteria are harmless, but
there are those that aren't. We spoke by email with
Melissa Maker, host of the YouTube channel clean my Space.
She said all sorts of germs in bacteria can live
on and in your cup, especially if you are in
a shared space. Cold and flu germs tend to travel

(01:05):
and can easily land honor in your cup. Plus germs
from your mouth and hands will also transfer to your cup.
The warmer and damper the environment, the more pleasing for
bacteria to fester. Indeed, the laundry list of possibilities is daunting.
We also spoke via email with Dr Terry D. Connell,
professor of microbiology and immunology at the University of Buffalo.

(01:27):
They said strep staff and any number of resident or
transient oral bacteria, which may include potential pathogens, may reside
in unwashed cups, and of course, if someone else should
drink from one's cup, bacteria from their mouths can be
transferred into it. Office environments are particularly conducive to the
spread of bacteria. Dr Childs Gerba, a professor of microbiology

(01:49):
at the University of Arizona, published research findings back in
the Continue to Rock Our Worlds Today. His team assessed
bacteria found in office coffee cups and coffee preparation areas,
and they discovered that fort of cups tested or contaminated
with coliform bacteria otherwise known as vehicle bacteria. And most

(02:09):
of the time these bacteria are not harmful to people,
but they certainly can be, especially to those with weakened
or compromised immune systems. The kicker Dr Gerba's team found
that a small office cup washer sort of like a
mini dishwasher was all it took to eradicate these and
other types of bacteria. The problem is most people think
of simple rinse and wipe is enough to keep germs

(02:31):
at bay. However, this approach is definitely not enough to
tackle such formidable opponents. Dr Connell said bacteria can adhere
to the surface of the cup. Washing with soap is
essential to remove those bacteria. That's why public health officials
in England put out a plea back in January for
reusable cup users to thoroughly wash receptacles after every single

(02:53):
drink to prevent the spread of illness. This was in
response to a spike in reusable cup use since the
nation started in posing a so called latte tax on
disposable cups. Proper cleaning grows even more critical if the
coffee in question has been doctored with cream or sugar.
Dr Connell explained both of those substances contain nutrients for

(03:14):
bacterial growth. While water washing will remove most of the sugar,
the oils and proteins in milk or cream require the
use of soap to remove. Soap is what's known as
a surfactant. Molecule of soap can grab hold of oily
particles at one end and molecules of water at its
other end, thus helping dissolve and rinse away even stubborn grime.

(03:36):
So here are the easy steps to lessen the germs
in your coffee mug. Wash your cup with soap and
water after every use. Wash with a paper towel rather
than a shared sponge. Dry the cup with a paper towel.
And if your cup has a lid, remember to wash
that too. Today's episode was written by Aliyahit and produced

(03:58):
by Tyler. Playing brain Stuff is a production of I
Heart Radio's How Stuff Works. For more in this and
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