Food grade shellac

Maybe it’s just me, but when I go to the store to buy apples and find them boxed with a label that reads, “Food grade shellac” as the ingredient keeping them bright and shiny, I get nervous.  Is shellac really meant to be food grade? And what exactly does that mean? And how much food grade shellac can I eat before my stomach lining starts to get all hard and shiny bright? Until I feel much, much better about eating shellac, I think I’ll just stick to apples with food grade cannuba wax which, at least, is a natural product found in my ear.