In commercial practice, heating of milk is the most widely used unit operation in the manufacture of a wide range of dairy products. The time/temperature combinations applied range from £65°C (thermisation) for a few seconds to 150°C for a few seconds for ultra high temperature (UHT) sterilisation. Milk for the manufacture of yoghurt is heated at different temperatures and the reported treatments,including the processing of liquid milk, are illustrated in Table 2.15.