Whether milk powder can be drunk after it has expired depends mainly on how long it has expired and who is drinking it. If it is unopened, it is only two or three days overdue, and the milk powder can still be drunk, but if it is overdue for ten days and a half months, or even longer, it can't be drunk.
The unopened expired milk powder has just expired for two or three days. If you are an adult, you can drink it, because adults have better physical fitness and fully developed gastrointestinal functions. But if it is an infant, no matter how long it expires, it can't be drunk any more, because the intestines and stomach of infants and young children are not fully developed, and it is easy to have diarrhea after drinking.
Milk that has expired before it is opened may cause harm to the body, such as allergies, diarrhea, stomachache and so on. Therefore, if milk has expired for ten days and a half months, it is still not recommended to drink it, so as not to have a negative impact on the body.