Well, this is gross.

If you work in an office then you'll have noticed that people have their own mug which they keep at their desk. There are a number of reasons for this, but mainly to always have a cup on hand for your tea or to avoid sharing with others who might not clean cups as well as you do. Well, if you are one of these people who hoards a trusty desk cup then you might want to think again. It turns out that cup is harvesting a lot of bacteria. According to Men’s Health, it contains "a colony of germs." Charles Gerba, Ph.D., a professor of environmental microbiology at the University of Arizona, has said that twenty percent of office mugs carry fecal bacteria, and 90 percent are covered in other germs. What's more that kind of bacteria can live on a mug for 3 days. It makes sense really because a lot of the time they are only hand washed which doesn't give it the thorough clean it deserves. Furthermore, the sponges used in offices are often very old and contain bacteria which transfers to the cup. The only way to prevent the transfer of bacteria is to make sure it gets properly cleaned each time you use it and to have a mug which is straight forward, without a lid or anything on it, so that it's easier to physically clean.