After boiling, the milk developed white "curds," a bit like tofu pudding, but it doesn't seem to have any strange smell. I'd like to ask, is this milk still safe to drink?
Boiling milk with red dates
Dr. Hu Changli from the Key Laboratory of Functional Dairy Products at China Agricultural University answers: It should be noted that normal pure milk will not form white curds or precipitates during a short period of boiling. However, a layer of "milk skin" may appear on the surface, which is just milk fat and is nothing to worry about.
The appearance of white "curds" in heated milk can be attributed to two reasons. First, certain proteases present in the milk alter the structure of its proteins, thereby destroying the milk's stability and causing denaturation and coagulation during heating. This is primarily due to improper storage, such as keeping the milk in a high-temperature environment for an extended period. Although such milk may not be past its expiration date, it is not recommended for consumption. Second, the proliferation of residual microorganisms in the milk causes its acidity to change, which further disrupts its stability, leading to "curds" after boiling. This indicates that the milk has spoiled, a common occurrence with milk that has passed its expiration date. In summary, milk that forms "curds" after heating is not recommended for drinking. Furthermore, spoiled milk might show signs of swelling, have an off-odor, or contain flocculent substances even before heating, so consumers should pay close attention to these indicators.