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What's Brewing In Your Coffee Maker?

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DALLAS (CBS 11 NEWS) - You could be brewing up more than you realize in your morning cup of coffee or tea.

The I-Team swabbed ten one-cup coffee machines inside the homes of several Dallas families.

Coffee Maker 4
(credit: CBS 11 News)

Armstrong Forensic Laboratory in Arlington plated the swabs and reported the findings to us. We took the report to Infectious Disease Specialist Dr. Cedric Spak. And, then we returned to the families to reveal what we discovered. Need-less-to-say, they were a little surprised!

Dallas mom, Stephanie Brink was stunned to hear that her machine had pseudomonas aeruginosa- a bacteria that grows in standing water and pipes.

"I'm shocked, I'm shocked," she said. "I thought you would find something but not something that would really make us sick."

Heather Dunston, a mother of three was in for an even bigger surprise. The I-Team found enterobacter on her machine. That's a coliform - a bacteria from your colon.

"Coliform is below the belly button or below the belt, so it can be front or back and it can cause infection," Dr. Spak explained.

Coffee Maker 5
(credit: CBS 11 News)

And, our very own I-Team Senior Investigative Reporter Ginger Allen was in for a big surprise as well. Dunston was not the only one with a coliform on her coffee machine. Klebsiella, another coliform, was found on Allen's machine.

"And, that can't come from anywhere above the belt?" Allen asked. "Uh no," said Dr. Spak. He politely explained that klebsiella, and other coliform, can easily get on our appliances. He suggested children may transport it from the bathroom to the kitchen. Dr. Spak says it serves as a good reminder to wash your hands!

Armstrong Microbiolist Karen Deiss says the 10-machines we swabbed contained 11- different types of bacteria . They grew nearly 40-thousand colonies of germs. And we even found mold.

Our experts say people suffering from severe heath problems can get very sick from the germs we found. Healthy people may experience an unexplained stomach ache.

But for all of us...the solution is simple:

1. Clean your machine regularly - run vinegar through it often.
2. Use filtered water rather than tap.
3. Change the water after each use.
4. Leave the lid off to allow the machine to air out.
5. Wipe it down like you do your other appliances.

One-cup coffee makers are a convenience but how do they compare to your regular old coffee maker? The I-Team looked at similar study on regular pots. Our tests found that one-cup machines have twice as many coliforms as the regular pots.

Some encouraging news for our CBS 11 team...the cleanest machine we swabbed was in our CBS 11 break room. It contained staph. Dr. Spak said that likely means we are cleaning it often. Staph is typically found on human hands.

Keurig Green Mountain send us the following statement:

"Keurig Green Mountain is committed to creating brewers and packs in a way that brews the perfect cup of coffee, tea and other beverages while maintaining the highest safety standards.

Similar to other household appliances, Keurig brewers requires basic maintenance in order to keep them clean and functioning properly. For best results, we recommend descaling every 3-6 months using our descaling solution to keep the brewer free from scale or lime build up. Vinegar may also be used. We recommend users consult their brewer user manuals or visit our website at for video instructions or to purchase the descaling solution. The water reservoir should be cleaned weekly by wiping it with a damp, soapy, lint-free, non-abrasive cloth and rinsing thoroughly. It should not be placed in the dishwasher.

If the brewer is not used for several days, we recommend running several cleansing brews through to remove any internal standing water. If the brewer is stored for a length of time, we also suggest descaling prior to use."

(©2015 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)


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