Way back when I was at school, they were known as "the Witches" - probably in reference to the meal ingredients:

"Fillet of a fenny snake, Eye of newt, and toe of frog, Wool of bat, and tongue of dog, Adder's fork, and blind-worm's sting, Lizard's leg, and owlet's wing, Scale of dragon; tooth of wolf, … Read more

Are you talking about the ladies/ men that cook at schools?

If so, they have a very hard hot job. Getting a meal in most cases two meals a day ready for 770+ kids is no easy feat. No one ever thanks them.

No.... That's not true.

Geez ! Where in the heck did you hear that? Totally untrue !