Is Your Coffee Cup Lid Contaminated?

Q. I love the lattes from the local coffee shop. I usually grab a cup on my way to the office. What I don’t like is when the barista slaps the lid on my cup. She uses the palm of her hand to snap it closed.
I worry that this is unsanitary, since I like to sip my coffee through the spill proof lid. Am I being paranoid?
A. As far as we can tell there has been no research on coffee cup lid contamination. If the barista is also handling money, that could facilitate the spread of germs. It is unrealistic to expect a server to wash hands between every cup of coffee, but it is certainly reasonable to ask to put your own lid on your coffee cup.