Do you wash your coffee cup every day after using it? You might be wasting your time. According to to The Wall Street Journal,you don't need to wash your coffee cup every day, unless you happen to share your coffee cup with someone else, or if you add cream and sugar to your coffee cup. Before your run away screaming from the germ-tastic idea, let's break this down to figure out if it's actually OK to do.
Infectious disease expert Jeffrey Starke, a pediatrics professor at Baylor College of Medicine, tells The Wall Street Journal that even though there might technically be germs in an unwashed coffee cup, it's fine because they are yours. These germs, even if you're sick, won't hurt you again if you drink out of the same mug. "Very few viruses can exist for more than an hour on an inert object" Starke said.
In fact, Starke says that washing your coffee mug every day might actually be worse for you, especially if you're using an old sponge at your office. The sponge in the break room probably has the highest bacteria count of anything in the office," Starke explains. If you are washing your coffee mug with said sponge, it might benefit from a quick ride in the microwave to kill off germs.
Read more: 1 Minute to a Cleaner Sponge
So no, it looks like we shouldn't be super concerned with drinking out of an unclean coffee mug. "Of all the things people have to worry about, getting sick from an old coffee mug is at the bottom" says Strake. But does that mean you shouldn't take the minute to walk over and wash your coffee mug? Maybe with a clean sponge or maybe in the dishwasher if available?
Let's consider the social implications of not washing your coffee cup as well. Maybe it's cool to acknowledge that you don't need to wash your mug, but do you think your coworkers are going to enjoy this unclean mug sitting on your desk? Of all the lazy things I try to get away with at the office, this is the one I can't get behind. The amount of time it takes to actually get the job done — to wash a single mug — shouldn't be a burden. In fact, it's probably the laziest thing I've heard of this year outside of "Millennials" claiming that eating cereal takes too much effort.
So while it might technically be safe to drink coffee out of yesterday's unclean mug, I don't really understand why you would need to do that.