Proper Temperature
Milk should be kept at a temperature not above 50° F. during transportation. The cans or bottles should be properly covered, sealed, and the milk protected from too much agitation.
Because milk undergoes a very rapid change, beginning almost as soon as it is drawn from the cow, it is necessary to either consume it in a short time or provide some means of preserving it. Milk soon deteriorates, becomes sour and unfit for use as food.
The best means of preserving milk is to keep it at a low temperature. Bacteria are not destroyed in low temperature, but the activity is inhibited and their development retarded. In this way milk is kept from souring and from undergoing fermentative changes. The digestibility and character of milk are not changed by cold, and it will be sweet for a day or even longer if kept at a temperature under 50° F.
An entirely sterile milk may be furnished only by raising the temperature to 248° F. for at least two hours, but this destroys the milk ferments. There are certain changes produced by boiling milk which renders it less desirable for food, making it less digestible. It is, therefore, especially undesirable for infants.