Millions of people rely on a cup of coffee (or two) to get them going in the a.m. But it turns out, you may be getting a bit more than you bargained for in your morning mug.

KDKA-TV of Pittsburgh did swab tests on 28 single-serve coffee machines, eight of which were in Pittsburgh and the remainder in Chicago and Dallas. In more than half of the appliances, results showed millions of bacteria in the “water tank, coffee pod compartment, spout, and tray.” Eek!

In one of the Keurigs examined, “4.6 million colonies of bacteria and mold” were discovered. In other machines, bacteria such as “E.coli, staphylococcus, streptococcus, and pseudomonas aeruginosa” were also found. In small doses, some of those bacteria aren’t harmful, but according to University of Arizona microbiology specialist Kelly Reynolds, “at some point they’ll grow to levels high enough to cause sickness,” she told ConsumerAffairs.com.

Since 27% of coffee lovers use single-serve machines, this discovery is stomach-churning but not entirely surprising. Many people don’t remember to clean their machines on a regular basis, and, as moist environments, coffee machines can become breeding grounds for the bad stuff.

Make sure your cup is filled with just coffee when you prep your morning brew, and follow these crucial cleaning tips:

• Wipe it down daily and take off any removable parts and clean with dish soap and water.
• Change your water regularly.
• Leave the reservoir’s lid open use so it can thoroughly dry out (germs love moisture!) after every use.
• Once a month, cleanse the machine by running equal parts vinegar and water through it by following these steps.

(Excuse us as we go clean out our coffee machines now.)