The process is the following:

1. centrifugation of cow milk to eliminate impurities;
2. standardization of the composition in complete solids and lipids to obtain a final product with constant characteristics;
3. thermal treatment at 120-130°C for 30 seconds (the high temperature is necessary to normalise the mineral and protein component) and homogenization;
4. concentration through evaporation vacuum at 45-55°C (or through cryoconcentration or inverted osmosis).
5. dehydration by spray-drying or lyophilization;
6. packing in light and humidity-impermeable packages

In truth powdered milk is obtained in different ways:

• Spray processes. These have varying applications. The nebulisation of milk is performed in a turbine at 7000-8000 rpm, placed in a tower with air at 120-150°C: in this way the small drops of milk escaping from the turbine are dried before reaching the walls of the tower. They drop to the bottom and are removed mechanically. In other spray processes, nebulisation is obtained by the compression through thin holes, and dehydration is obtained by the circulation of hot air. During the spray processes, it is necessary to pre-concentrate the milk in order to avoid excessive nebulisation which involves an excessive absorption of the air on the particles of powdered milk, and the subsequent oxidative modification. Powdered milk must be immediately cooled and kept in an inert environment.
• Crosscurrent processes. These heat the nebulised milk in 70-metre towers while a slow air current or inert gas is injected from the bottom. The milk powder collects on the bottom and is automatically removed.
• Foam processes. The milk is heated in advance at 63°C and is later vacuum concentrated to produce a residual dry titre of 50%. It is then homogenized at 57° and, during the homogenization, gas nitrogen is blended into the mass. It is cooled to 10°C and then heated to 49°C, shaking it in a vacuum. The product is fluffy and soluble due to the presence of gas inclusions.

For powdered milk solubility is very important; it is therefore submitted to instantaneity. The milk, obtained via the spray process, is sent into the instantaneity room on conveyors. There it is kept in contact with water up to a total of 10% of its weight. Later it is cooled down and dried up to 3-4% of water. Milk is easy soluble and will keep its solubility.