I was on an AA flight and the FA was serving drinks (using an ice scoop). She was a friendly sort of FA and talked to each passenger as she served the beverages to them. One of the passengers asked for a lemon in his drink. She took it with her bare hands and put it in his drink. Then he, I guess (since I could only watch was going on but not hear the conversation), challenged her to try sucking on a lemon. She did, made sour-lemon faces, then put her fingers to her mouth to take it out. She didn't just touch only the rind of it (not that that would necessarily be all that much better since she put the whole thing in her mouth) but had her fingers all over it after it had been in her mouth. Then she threw it away and continued serving drinks without washing her hands, continuing to grab lemons and limes with her bare hands to put in drinks.