If you can buy the food at a supermarket, can't you cite a product page? Presumably that would include a description of the product. Or is that not good enough of a citation?
Retail product listing URLs change constantly. They're not great.
And then you usually want to describe how the food is used. E.g. suppose it's a dessert that's mainly popular at children's birthday parties. Everybody in the country knows that. But where are you going to find something written that says that? Something that's not just a random personal blog, but an actual published valid source?
Ideally you can find some kind of travel guide or book for expats or something with a food section that happens to list it, but if it's not a "top" food highly visible to tourists, then good luck.
