Your Office Coffee Mug Is Gross, Says Science

Professor finds all kinds of germs in desktop coffee cups
Wikimedia/Øyvind Holmstad

Science has found another way to ruin everyone's morning. First it tells us that coffee can reduce physical pain and the risk of diabetes, but then it says, "Oh, and by the way, there are all kinds of unspeakable horrors in that coffee cup."

"Twenty percent of office mugs carry fecal bacteria," said professor Charles P. Gerba of the University of Arizona. "And 90 percent are covered in other germs."

According to UPI, Gerba said people shouldn't sip their coffee for longer than an hour or so, because colonies of germs live and breed in them.

"In an office, most people tend to clean their cups with bacteria-laden sponges or scrub brushes instead of a dishwasher. That bacteria transfers to the mug and can live there for three days," he said.

Gerba suggests taking the mug along on morning and evening commutes so it can be cleaned in a dishwasher.

"At the very least, wash it with hot water, soap, and a paper towel. If it sits unwashed on your desk after being used, germs will start reproducing immediately—and bacterial colonies grow even when the cup contains nothing more than a coffee ring," he said.


Gerba's previous research into the deadly germs of the modern office found that the phone, computer, mouse, and photocopier are all probably covered in horrible germs. According to his research, the cleanest object in the modern office is the toilet seat.