I don't think you can bring down the entire Bronze Age civilized world if you're spending all your time slurping raw bats, which is to say, you haven't gone back far enough. And if you go further back still, you're going to reach tribal nomads with a rich oral legacy of survival wisdom; I don't think they were boiling toilet grease stew, either.

Basically, modern China--the product of dozens of apocalyptic events, starvation heaped on starvation--is presumably without, or nearly without, precedent with regard to their "unique culinary/hygienic traditions". I sympathize, but also, what the fuck guys get your shit together and stop rubbing raw offal garbage on your faces.