Pasteurised milk wasn’t legally mandated in Australia until the 1950s, but in 1897 the New South Wales Fresh Food and Ice Company advertised that all its milk would be pasteurised. The process developed by Louis Pasteur in 1864 was originally applied to wine and beer, but was adopted for milk in the 1880s in Germany, where the first commercial pasteuriser was made in 1882.
Pasteur wasn’t the first to use heat to kill bacteria in foods and drinks. However, previous heat treatments involved high temperatures and, often, prolonged periods of heating to achieve sterilisation. As a result, although safety and keeping qualities were improved, taste and texture were changed. This was unimportant for cooked foods, but sterilised milk had a markedly inferior taste to fresh milk.
Pasteurised milk was heated for a relatively short time to a comparatively low temperature of around 60° Celsius then rapidly cooled. The process killed the bacteria that caused diseases such as tuberculosis and brucellosis, which were commonly present in milk in the 19th century.
In the early 1890s there were reports of cream and butter being pasteurised in Tasmania but the New South Wales Fresh Food and Ice Company seems to have been the first major company to advertise its pasteurised milk in 1897. The same year, the Victorian Minister for Agriculture arranged for a series of “exhaustive tests” of the process by the government chemist.
Pasteurisation of cream for butter making attracted the interest of the dairy industry in the early 1900s. Various newspaper reports drew attention to the practice in Denmark, where it vastly improved the keeping qualities of the butter. An article in the Brisbane Telegraph in 1908 reported that pasteurisation of milk in a German town had reduced the infant mortality rate from 47 per cent to zero over two months.
Other dairy companies gradually began to adopt the process but pasteurisation remained optional through the first half of the 20th century. As late as the 1940s, some milk deliveries to homes still involved ladelling the milk from a galvanised drum into a billy left outside by the householder. As bottles came into common use, more dairies began to pasteurise their product. The school milk program instituted under Federal Government auspices in 1951 required that all milk supplied to school children be pasteurised.
In the 1950s, the various state legislatures passed Acts requiring that all milk sold be pasteurised. In Victoria, the Milk Pasteurization Act 1958 specified that no-one should “sell or deliver milk except milk pasteurized at licensed pasteurizing premises and bottled and sealed as prescribed”.
It is still illegal to sell unpasteurised milk for human consumption in Australia. Although tuberculosis and brucellosis have been eliminated, there is still concern about other pathogens including Listeria, Escherichia coli, Salmonella and Staphylococcus. Cheese made from raw milk is now available but is subject to strict controls.