It may depend on when you went to grade school. I'm not trying to be insulting here. But many of these severe food allergies to things like peanuts and milk are pretty recent in their being widespread enough to be noticed.
Or perhaps many of them are fabricated. I know a family whose child is suddenly deathly allergic to peanuts and the other children must be controlled for her sake.
Odd she didn't have this deadly problem for 3 years.