I promise to no longer touch any ones keyboards at work if you all promise to keep your hands off mine.
After seeing a twitter post on this, I read an article at the Beeb on how; and I definitely quote:

Research by the University of Arizona last year found the average office desktop harboured 400 times more bacteria than the average office toilet seat.
…
“Should somebody have a cold in your office, or even have gastroenteritis, you’re very likely to pick it up from a keyboard.” … one of the causes of dirty keyboards was users eating lunch at their desk, with crumbs encouraging the growth of bacteria. Poor personal hygiene, such as not washing hands after going to the toilet, could also be to blame.

Read more at the BBC well before you have lunch.
This is also a good time, going into the colder months in Southern Australia, to brush up on your coughing skills; and it is about this time last year I discussed the best way to do this.