Finnish and British researchers swabbed trays at the Helsinki Airport and discovered that half of the samples were contaminated with rhinovirus or adenovirus—two categories of common viruses that can trigger cold-like symptoms.
http://mentalfloss.com/article/556466/bins-at-airport-security-are-incredibly-dirty-germs
This type of news is provocative, but it needs to be put in perspective. Anything that lots of people touch all day, and isn’t regularly cleaned, is like this. Door handles. Pay phones. Fuel pumps at gas stations. It is just the nature of things.
And they’ll say “worse than public toilets”. That’s because public toilets get cleaned a lot.
These germs are not airborne. You need to ingest them to potentially get sick. When someone sneezes or coughs into the air, and you are close by, that is how.
Otherwise, feel free to touch all of those germ-riddled surfaces, just don’t put your fingers in your mouth, or on food, without washing them first. Basic stuff.