Airplane bathrooms

In 2014, a microbiologist swabbed the bathroom door, faucet handle, toilet, sink, and a tray table on a flight from San Francisco to Phoenix. Lab results showed that "the airplane's bathroom sink was by far the dirtiest with almost half a million bacteria present including fecal bacteria in the tiny airplane sink."

Also, FYI, washing your hands on board might not really help: In 2004, the Environmental Protection Agency found high levels of fecal bacteria in the drinking water of 15 of the 327 planes it tested.