Study: Single-Cup Coffee Makers Brew Lots of Germs, Too Wake up and smell the bacteria. Read on to learn how to clean your office's communal machine.

By Kim Lachance Shandrow

Opinions expressed by Entrepreneur contributors are their own.


Ponder this the next time you sip a cup of Joe at work: That single-cup coffee maker everyone at your office loves -- and constantly touches -- isn't just an environmental waste factory. It's also a big-time bacteria brewer.

Sorry to kill your bean buzz, but there are likely dozens of different types of nasty microorganisms crawling around in your pod-based communal caffeine machine, specifically inside its exterior drip tray, according to a study published in Scientific Reports.

As part of what they're calling the "first systematic analysis of coffee machine-associated bacteria," researchers at the University of Valencia in Spain swabbed 10 individual coffee pod-style Nespresso coffee makers. They tested them in both office and home environments. The result: the discovery of dozens of major (and rapidly colonizing) types of bacteria littering the machines' coffee waste reservoirs. None were detected inside the coffee pods themselves.

Related: Long Live the Coffee Drinker: Why You Shouldn't Feel Bad for Being a Coffee Addict

Researchers also found that the more a machine is used, the more bacteria it will contain. Some of the germs uncovered in the investigation include unappetizing tongue-twisters, like stenotrophomonas, sphingobacterium, ramlibacter and acidovorax. These stubbornly resilient bacteria survive despite some pretty tough conditions -- the naturally antibacterial qualities of roasted coffee itself and brewing machine temperatures that climb as high as 204 degrees Fahrenheit.

And there you have it, scientific confirmation of what the office germophobe already suspected: single-cup coffee machines are veritable germ orgies. Traditional coffee makers aren't much cleaner either.

Researchers reckon that we only have our dirty selves to blame. They think the coffee-adapted bacteria they detected -- up to 67 different kinds in a single brewer -- can probably be attributed to unwashed hands.

Related: You're Drinking Coffee All Wrong. Here's How to Fix That. (VIDEO)

Like washing your paws after using the loo, luckily, the fix is easy. To significantly decrease bacterial growth, the researchers suggest you rinse the coffee pod intake area of your brewer once a week with warm, soapy water. It's about the best you can do. Try as you might -- nature wins. You'll never be able to get rid of all of the little buggers.

Here's how to clean your single-cup caffeine delivery device in a few quick steps:

1. Remove all of the water from the machine.

2. Make sure there isn't a coffee pod in the intake area.

3. Fill the machine's water reservoir with half of a cup of white vinegar and one cup of cold water.

4. Brew the water-vinegar mixture twice.

5. Rinse out the water reservoir.

6. Remove all detachable parts from the machine -- the water reservoir and lid, mug stand and coffee pod holder.

7. Wash them in warm, soapy water and dry.

8. Finally, wipe down the machine surface with a clean, dry cloth and a damp cloth where needed.

Oh, and please don't forget to wash your hands before you brew your next jolt.

Kim Lachance Shandrow

Former West Coast Editor

Kim Lachance Shandrow is the former West Coast editor at Previously, she was a commerce columnist at Los Angeles CityBeat, a news producer at MSNBC and KNBC in Los Angeles and a frequent contributor to the Los Angeles Times. She has also written for Government Technology magazine, LA Yoga magazine, the Lowell Sun newspaper,, and the former U.S. Surgeon General, Dr. C. Everett Coop. Follow her on Twitter at @Lashandrow. You can also follow her on Facebook here

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