【明報專訊】Yes it is true, westerners eat rotten milk instead of tofu. They take a pail of milk, add bacteria and let it sit in a warm place. The bacteria eat all the milk and make waste. A day later the milk in the pail has turned into a mixture that includes live bacteria, dead bacteria and their waste. This semi-solid mixture is called yoghurt. Greek yoghurt is made by straining regular yoghurt through a cloth to remove some of the liquid.
When yoghurt is warmed up some more, it will split into two parts. The liquid part is called whey (乳清), the soft solid is called curds (凝乳). In the old days whey was fed to pigs, today it is an expensive health food. The soft curds are salted and pressed together to make cheese.
Milk is a very good source of nutrition. However one could not store it for very long in the days before refrigeration. By removing the liquid part of milk, and adding salt, they could keep it longer. Cheese was a way of keeping milk.
The English only more recently started eating yoghurt; it is a Turkish food. The word yoghurt comes from the Turkish language. However the words milk, curds, whey and cheese are all from Old English.
As I write this I have my own pail of homemade yoghurt and a bowl of homemade cheese in the refrigerator. My family has been making their own yoghurt, and occasionally cheese, since I was a little boy.