Odds are you probably already own a single serve coffeemaker. Over the past few years these simple machines have been a popular choice for homes and offices, and according to Statista almost 30% of Americans own one.

Part of the appeal behind the single serve machines is the easy clean-up: you just pop a disposable pod inside, pour your coffee, then throw it away when you're done.

But there's a nasty downside to these machines. Tests reveal that they're breeding grounds for dangerous bacteria, including E. coli.

We know you're dying to make another cup right now, but learn the risks and how to clean your machine first.

Local CBS affiliates in 3 cities each sent swabs of coffee machines to labs for testing. The results they got back were shocking.

More than half of the machines they tested had mold or harmful bacteria lurking inside. The problem is that these are attracted to moist surfaces, so nearly every part of your machine - including the water tank, the coffee pod section and the tray - is a perfect breeding ground for diseases.

Other tests by ABC news found similar results. While experts say old-fashioned coffeemakers can also get moldy, they're easier to clean than today's machines.

Luckily, it's easy to protect your family from getting sick if you know what to do.

It's safe to say you're probably not cleaning your machine regularly enough, so make a habit of doing that, including wiping down parts like the tray and the spout.

If you don't use the machine for a few days, be sure to empty the water tank before using it. To be extra safe, some companies recommend running vinegar or a descaling solution through your machine every few months.

Once your machine is safe and clean, try making some of these Starbucks recipes to celebrate.

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