Powdered milk

Powdered milk is milk from which water has been removed until it becomes a powder. The primary purpose of this process is to preserve milk for extended periods without refrigeration, and to reduce its weight and volume during transport or storage.

When used, the powder is mixed with water to restore a liquid consistency. It is made from whole milk, low-fat milk, and skimmed milk. There is also a special type formulated for children, enriched with vitamins and minerals.

Production method

First the milk is cleaned and heated to reduce microorganisms (pasteurization). Then part of the water is removed using an evaporator under reduced pressure. Finally the concentrated liquid is sprayed into a hot chamber—a process called spray drying—where the small droplets evaporate immediately and become powder. There is also another method called roller drying, in which milk is spread on heated rollers.

Storage and quality

Skimmed powder milk lasts longer than whole milk powder, because the fat it contains can deteriorate over time (oxidation). For this reason, most producers remove oxygen from the powder or fill it with an inert gas. Heat and light cause the powder to clump and take on an unpleasant taste.

Uses

Powdered milk is used in homes, food manufacturing (bread, chocolate, drinks, and prepared foods), and humanitarian relief programs in areas where cold chains are unreliable. It is also added to rice milk, tea, and various beverages.