Would it have been offensive if the same typo had appeared in a recipe which simply called for freshly-ground pepper?
No ... everybody seeing "freshly-ground people" in the ingredients would have laughed their asses off, shouted "It's people! It's people!", and suggested the cookbook be retitled "To Serve Man".
Among all the atrocities that humans have committed on other humans, I'm unaware of organized cannibalism by non-black people on black people being any one of them. Therefore, it couldn't be construed as a reference to something bad someone's ancestors did to someone else's ancestors, because for something to be an offensive reference, there must be something for it to refer to
It's just a typo that got mangled by a spelling checker. Yes, a silly mistake. Nothing more sinister than that. And trying to blow it up into anything more important than it is serves no one except those who wish to divide and rule.
The real offense is that someone thinks spelt tagliatelle with sardines and prosciutto is food.