I think as we all know, the psychology is that if something looks clean and is clean, then you are most likely to keep it clean yourself, if it looks like no one cares then what is one more "mess" going to do. Most airlines are able to keep things reasonable, and the food sanitation is just bullock's, hands and lower arms should have a thorough cleaning before and after food preparation. It is not like your chef the the 3* restaurant has never gone to the bathroom before or even during service.