When I was visiting Shanghai, I learned to avoid a certain alley on my walk to the underground system. It always smelled incredibly, almost unbelievably bad – like there was an open sewer on the sidewalk. But I could never see any evidence of the smell's source. And then one day, I realised where it was coming from. It was the scent of the bustling snack shop at the alley's entrance. Their specialty: chou doufu, tofu fermented for months in a slurry of meat, vegetables, and sour milk.

For many Westerners like me, it's hard to believe you could get the stuff anywhere near your mouth without gagging. But the shop had a long, long line. And I've since learned that many Chinese people have the same feeling of disgust when they consider the habit of eating cheese.

Though eating dairy is becoming more widespread in China these days, letting milk go bad and then adding salt and extra bacteria into the mix still sounds pathological. Even very mild cheeses like cheddar or jack cheese are considered basically inedible, it seems – melting them on bread can help, but they rank very low on the taste totem pole, my Chinese friends tell me.