Milk is an emulsion of butterfat globules within a water-based fluid. Each fat globule is surrounded by a membrane consisting of phospholipids and proteins. Ordinary fresh milk sold for domestic use must contain a minimum of 3,3%fat and 8,5% fat-free solids. Most milk that is consumed via commercial sources today is processed in at least one of the following ways:
Milk is exposed to intensified temperature, usually 72°C, for fifteen seconds. This destroys all the pathogenic organisms, the heat resistant tuberculosis bacteria, as well as approximately 90 percent of all remaining organisms, without causing any visible changes.
Most liquid milk products are homogenised. This involves the breaking down of milk fats into small particles so that a layer of cream is not formed on the surface.
This is the deliberate modification of milk composition by removing milk fats to reduce the fat content to the required 3.3%, or to control the total solids composition of milk products.
Source: Parmalat