I’m quite sure there are cases of food being prepared in bad conditions but i can’t imagine it’d be any different from street vendors in Latin America. People in the neighborhood find out pretty quickly if a vendor is making people sick, their pride and reputation is on the line and often times that’s all they got because that’s what brings business in. Ask a local what their favorite stalls are and its difficult to be disappointed.
Really a shame that the government is making it harder for these folk to earn a living, it has the unfortunate effect of homogenizing what businesses succeed and you end up with a bunch of chain restaurants. Give me a hole in the wall place, those are the best.