This isn't a food hygiene issue. Or a Chinese one. It's a feature of viruses that they migrate from animal to human populations and back again. Flu is notable for it, and that (and its fast mutation) is why we can't eradicate it with a vaccine. Viruses migrate from animal populations to human ones all the time. They arise locally, are usually not very lethal or infectious and thus 'only' cause an epidemic and subside again. It could have arisen in a petting zoo in Surrey (an arguably more idiotic practice than an a Chinese street market, from a virology perspective!)
It is a luxury of middle class Westerners that we have industrialised agriculture and are far, far removed from our food source, and that our poor have a safety net which (while woefully inadequate) does not force them to catch and sell wild animals to eat or live. We are even luckier that we have enormous regulatory bodies dedicated (often at much ridicule) to our health and safety.
I don't wish to belittle handwashing, its very important, and few people do it frequently enough or adequately. But this is a respiratory illness. It's mostly spread by droplets as you breathe (enormously spread by coughing and sneezing) which no amount of hand washing, or food hygiene will prevent. Thats why its so infectious, and our western habits of congregating in small, heated, enclosed spaces and then going to different small crowded enclosed, spaces often a very long way away is what's responsible for its rapid and wide spread. That you can be infectious with no symptoms for a long time, and that the virus is not very lethal is most of the rest of it. The reason we have not had a pandemic since 1918 is largely a matter of luck that a virus with the right level of spread and severity has not crossed the barrier in that time.
Interesting, one of the few diseases we have managed to eradicate by vaccination, Smallpox, has been managed precisely because it is not able to cross the species barrier, and thus cannot 'hide' from herd immunity (be it naturally acquired or vaccine acquired) in animals.