> would to my first- and secondhand knowledge at the very least exclude Mexican and Italian cuisine from being distinct. Neither one really exists as a coherent cuisine in the way you seem to imagine, and if you talk to a native of those countries they'll very quickly tell you that the foods you think of as "Mexican" or "Italian" are actually from specific regions of those countries.

I don't know Mexico well enough to comment, but yeah there absolutely isn't a unified "Italian" culture (perhaps there is the beginnings of one) and it's a mistake to think of one (not just in food but in other matters as well). Just as there is no "Chinese" food, there are several distinct Chinese food cultures.

> Your second requirement—that it be not eaten elsewhere—would likewise exclude every major exported food culture. Do the Italians no longer get to claim spaghetti because an American mom makes it as a quick dish at home for her kids?

At some point it just becomes generic food yeah, just like trademarks. I'm sure for the first people to bake bread it was a unique cultural food, but it would be madness to call that Mesopotamian food now, it's just food.