Milk is chilled in bulk refrigerated vats on each farm as soon as the cows are milked.These vats hold the temperature below 4C until the milk is picked up in stainless steel bulk tankers. The tanker driver grades the milk and takes samples for the testing required by the NSW Dairy Corporation.
At the factory, milk is pumped from the road tankers into stainless steel milk silos.
Laboratory tests measure the milk's butterfat and protein content. The results are used in setting the price paid to the dairy farmer. The milk is also subjected to bacteriological analysis and tests to determine its keeping quality.
All milk sold or processed in Australia is pasteurised. During pasteurisation, milk is heated to 72C, held for 15 seconds then cooled back to below 4C. The process destroys any harmful bacteria which may be present, improving both milk's safety and keeping qualities without affecting the flavour, creaminess or calcium levels.
Homogenisation of milk for some end uses ensures products of consistent fat dispersement. This process involves subjecting pasteurised whole milk to pressure which breaks up the fat globules, leaving very small particles which do not agglomerate after the process. This means the cream remains evenly distributed through the milk.
Large stainless steel centrifugal separators are used to separate whole milk to provide the cream and skim milk for further processing (in a 1:9 ratio). When milk is separated, the cream has about 38% butterfat and the skim milk has a butterfat level of less then 0.05%. The cream is used for making butter and ice-cream as well as being packaged for sale.
The skim milk is used to make powder and concentrates which are used in the manufacture of a range of other products such as ice-cream.