If you reuse your coffee mug at work, you are definitely doing your part to help the environment.

However, you are probably putting yourself at risk by doing so.

You won't believe what Men's Health says hangs out on that mug you drink from every day.

I'll just give it to you straight. It's fecal bacteria. Yup...fecal bacteria on your favorite mug.

Colonies of germs are living in your favorite cup. Twenty percent of office mugs carry fecal bacteria, and 90 percent are covered in other germs.

-- Charles Gerba, Ph.D., professor of environmental microbiology at the University of Arizona

It sounds nasty, but think about what might be on that sponge that you clean your mug with at the end of the day. That's assuming that you clean your mug every day instead of just rinsing it out before you hit the door.

So how can you continue to use your favorite mug without it becoming a cesspool of nastiness? Here are some tips:

  • Don't nurse a cup of coffee for longer than an hour or so.
  • Bring your mug home daily to be washed in the dishwasher.
  • Make sure it goes through the dry cycle, which uses the hottest temperatures and zaps every last germ.
  • If you can't take your mug home every evening, be sure to wash it thoroughly in hot water and soap and dry it with a paper towel. Do not use the nasty sponge in the office kitchenette.
  • If you leave your coffee mug on your desk without washing it, bacterial colonies will begin reproducing immediately -- even if the mug only contains a coffee ring.