Dairy Technology

Bulk Milk Collection

The holding of milk in cooled vats on farms for the collection by road tanker had been introduced in California about 1929 and tried out in Western Australia in the 1940s. The savings in transport costs and the improvement in milk quality over the old can delivery of milk were obvious. Tankers were used for market milk in Victoria in 1949 and in 1957 the factory at Archie's Creek in Victoria organized tanker pick-up from farms on which the milk was cooled by chilled water and held in insulated vats for collection.[186] Chilled water may have been satisfactory for short distances in coastal Gippsland but in the inland areas and on longer hauls refrigeration was essential and bulk milk collection could fairly be said to have been launched by Kraft at a field day in the Strathmerton district on 24 September 1957.[187] Special financing arrangements were made for farmers willing to install refrigerated vats and in the 1963-4 milk season Kraft's Strathmerton factory was the first in Australia to be wholly supplied with bulk farm-refrigerated milk.

This advance in milk handling was not without problems. The Weights and Measures Branch had to be satisfied about the calibration of vats and the measurement of milk volumes. A minimum standard for the rate of cooling of the milk had to be established and this governed the size of the refrigeration unit and hence the cost. Finally, as already noted, the problem of cold tolerant psychrophil contamination became apparent in the seventies. Nevertheless, this technology is now general.

Dried Products

Roller drying had been introduced in the 1920s for skim-milk, buttermilk and whey, but was never really satisfactory because local over-heating on the rollers led to burnt particles of powder which marred the products. Spray drying had already appeared in Australia before the Second World War and by the end of the forties was rapidly replacing rollers which, except for some special uses in the confectionery industry, have now disappeared. Spray drying is versatile and flexible. It is used for milk, whey, buttermilk and cheese powders, even for butter powder, and for a number of formulated dairy based products. Both roller and spray drying were introduced from overseas, but their application to Australian milks called for much study of and adaptation to Australian conditions. In this CSIRO's work has been crucial, especially that on the influence of seasonal factors and storage conditions on the reconstitutability of milk powders per se and in relation to re-combined products.[188]

Cheese

Cheese mechanization as now understood began during the war. Labour shortages led J. E. Sharkey, manager of the then Kraft factory at Drouin in Victoria, to propose in July 1941 the installation of a perforated trommel to 'work' the cheese curd mechanically and so to expel the whey. The plan was adopted and the mechanization of cheese making thus began at Drouin.[189]

Australian Academy of Technological Sciences and Engineering