While produce stickers are not exactly what you would call edible in the sense that you are not really encouraged to eat them, it's not like the FDA is going to countenance food items being labeled with deadly poisons. Instead, they have a set of regulations intended to ensure that the accidental ingestion of such a sticker will be fairly harmless. As the FDA classifies produce labels, they are known as food contact substances, a term that is applied to food packaging.

Some people, however, have misconstrued the fact that produce labels are subject to such regulations as meaning that they are actually made from paper that has been specially manufactured to be edible. With most produce labels, this is not the case. Snopes investigated these rumors of produce stickers' alleged edibility and found them to be "mostly untrue."

That being said, they also did not uncover any evidence that consuming such labels is particularly dangerous, either. They did note that some anecdotal evidence suggests people may have choked on produce stickers, although it seems none of the reported choking incidents were fatal or even all that serious. To sum up: You should be perfectly fine if you swallow a few stickers by accident, but you will probably enjoy your apple more if you remember to peel them off first.