If there are clots in the milk after boiling, can I still drink it?

Ms. Zhang, a reader from Hubei, asked: I like to drink hot milk. A few days ago, I found that white "clots" appeared in the milk after it was boiled. It looked a bit like tofu pudding, but it didn't seem to smell anything special. Friends around me said that they had encountered similar situations. I would like to ask, is it still possible to drink such milk?

Dr. Hu Changli from the Key Laboratory of Functional Dairy Products at China Agricultural University replied: It should be noted that normal pure milk will not have white clots or precipitation during the short-term boiling process, but there will be a layer of "milk skin" appearing on the surface of the milk. It is milk fat and there is no need to worry about it.

There are two reasons why white "curds" appear after heating milk. First, certain proteases present in milk change the structure of the protein in the milk, thereby destroying the stability of the milk and causing denaturation and coagulation during the heating process. This is mainly caused by improper storage of milk, such as storing milk in a high temperature environment for a long time. Although this kind of milk has not exceeded its shelf life, it is not recommended to drink it. Second, the proliferation of residual microorganisms in the milk causes the acidity of the milk to change, further destroying the stability of the milk, resulting in "curds" after boiling. This kind of milk has gone bad, which is more common in expired milk. In short, it is not recommended to drink milk that has "curds" after heating. In addition, spoiled milk may be "swollen", have an odor, or have flocs before heating, so consumers should pay special attention.