1, white with yellow, is a good curd; if you see green, black, do not buy. Good curd has a soy flavor, substandard curd will carry a smell of ammonia.

2, curd itself is fermented, so the bad speed will be much slower, this time as long as the scientific storage can be preserved for a long time, the method is very simple as long as a layer of sesame oil poured on the surface so that the curd and the air to isolate from the oxidation of the air can be.

3, curd easily is not bad, because the curd itself is mold fermentation and become, frankly, the curd itself has been "bad" once, how will it be bad again?

Good curd tastes smooth, and bad curd is sour, smelly or odor.