It does not surprise me at at all, my family owned a food distribution business for many years, we sold to restaurants, nursing homes, schools, jails, etc. some of the things that go on in the back of restaurants would disgust most people, it is not even just the fast food places. Working for the family business off and on over the years I have seen a number of such incidents myself, food hitting the floor, then picked up and cooked, ....
Here is one example, this incident took place about 40 years ago at a somewhat popular dining establishment located in a local hotel with a banquet hall, the place was normally open for lunch and dinner only, was a popular spot for local businessmen to have lunch. Our sales rep went in early one morning to collect a payment from the owners of the restaurant because their check had bounced, the night before they had hosted a banquet with steak dinners, that morning he saw they had kitchen staff going though the plates that had sat out all night, and were cutting off the bits of uneaten steaks. The lunch special on their marquee sign that day was steak tips and gravy. Infer what you will, don't worry the place is not there anymore, the hotel was even torn down about 15-20 years ago.