Lunchroom, what's a lunchroom?

"School Safe" snack from Treasure Mills

It just goes to show that I'm getting old. When I was a kid, in grades 4-6, no one, and I mean no one, had lunch at school. You all went home. Everyone had a mother at home ready to serve you a bowl of tomato soup and a grilled cheese sandwich. And no one was allergic to nuts.

But now every kid seems to have two parents who work and lunch is eaten at school in a lunchroom bereft of one of the singular joys of childhood, the peanut butter sandwich.

So the world is bombarded with snacks like this that are nut-free and peanut-free. My questions is, where did these peanut allergies spring from?