when I worked at Mc'ds for the week or so I could stand it, any food that was thrown out(wrong order, time expired, etc). was logged by a manager, every burger etc. That way they could monitor what was being thrown away(if folks were making mistakes on purpose, altering expired food, etc. so they could eat it later).
As for meals, when I worked for Mcd's you got 1 meal for each shift worked. An allotted ammount of money that would get you a "meal"(burger, fries, etc). if you went over the allotted ammount you paid the difference out of your pocket.
As much as I dislike Mcd's, food and corporation, those folks have their operation & what they do down to a science, and the costs broken down to the penny if not the 1/2 penny.