Please see section IV Specific Equipment Questions for information concnering the proper use of desiccants, compressed gasses, dry ice and oxygen absorbers. These are not shelf-stable vitamins and are sensitive to heat and light. The less heat and moisture the milk is exposed to, the better the vitamins will keep. A freezer could extend the shelf life, as long as the powder does not get moisture in it. If you had to put a time limit on the Mix'n Drink, for rotation purposes, I would date it at two years after the date of purchase.
Canned milk is covered in the next section , under caned goods.