Some years ago, I was in China on a caving expedition. I was the archaeologist and the EMT for the group. Naturally I expected a lot of cases of "Mao's Revenge". There were twelve of us, in country for a month, eating and drinking the local fare.

Not so much as an upset stomach. I am not sure what we consumed, because the wiser course was to just shut up and chew. I was told that our water was boiled regularly....