Jason Howland: Most of us aren't aware we are doing it.

We touch our face between three to 30 times an hour.

The problem, says Dr. Gregory Poland, is what we touch beforehand is often riddled with germs.

Gregory Poland, M.D., Vaccine Research Group Mayo Clinic: Bathroom faucets, door handles, escalator rails, computer terminals, anything that is commonly touched by the public.

Jason Howland: But how germ-filled are common objects? Let's start with money.

Gregory Poland, M.D.: Bad but not highly transmissible.

Jason Howland: Touchscreens, devices, phones?

Gregory Poland, M.D.: Bad.

Jason Howland: Restaurant menus?

Gregory Poland, M.D.: Really bad.

Jason Howland: Doorknob handles?

Gregory Poland, M.D.: Really, really bad.

Jason Howland: What about our computer keyboards?

Gregory Poland, M.D.: Those have been shown over and over again to be really grossly contaminated.

Jason Howland: These common surfaces aren't just gross. They can be a vehicle to spread cold and flu viruses, and make you sick. Dr. Poland offers these suggestions.

Gregory Poland, M.D.: First, keep your hands out of your eyes, nose and mouth. Second is either wash your hands with soap and water, or use hand sanitizer.

Jason Howland: And make sure you get your annual flu vaccine.

For the Mayo Clinic News Network, I'm Jason Howland.