Bizarrely McD's have one of the highest food and safety standards because of their huge popularity and global McEmpire success. (source: very good friend worked there. He since works in an upmarket gourmet place and insists that the standard in his new place is horrendous compared to what they had to do in McD's. Lawsuits are costly I suppose.  Avoid KFC though. The UK branches tested positive for fecal residue in their ice machines. Not one singular KFC, but multiple.  Here's a link about it.