The son of a tanner, Louis Pasteur was born in 1822 in the Jura region of France. As professor of chemistry at the University of Lille he was charged with finding solutions to the problems faced by local industries, namely the alcoholic drinks industry. The work he did in this field led into his work on bacteria and making dairy products safe for human consumption in a process that would become known as pasteurization.
Pasteurization
Pasteurization is a process in which raw milk is drawn through a system of pipes and ducts and heated to a temperature of around 140 degrees Fahrenheit for a period of half an hour, then heated to around 162 degrees Fahrenheit for a much shorter time, about a quarter of a minute. This process revolutionized dairy production and decreased food and waterborne disease outbreaks by nearly a quarter.
Ultrapasteurization
Ultrapasteurized milk undergoes the same process as ordinarily pasteurized milk, except that it is exposed to a much higher temperature. Ultrapasteurized milk is exposed to 191 degrees Fahrenheit, bringing the milk to the brink of boiling point. However, this extreme heat is only applied for a very short amount of time, usually only a fraction of a second. Milk is sometimes treated at even higher temperatures, this is known as Ultra High Temperature sterilization -- or UHT. During UHT treatment, milk is heated to 280 Fahrenheit for two seconds.
Taste
When milk has been pasteurized at a low heat, it keeps its organic and natural flavoring. This is because the heat is high enough to kill disease causing germs and bacteria, although it is not high enough to denature the enzymes in the milk and damage its calcium content. Once milk has been treated beyond 174 , this damage begins to occur and calcium has to be artificial re-introduced with additives, reducing its freshness and organic flavor.
Health Issues
While higher temperature processing methods may reduce the freshness of milk, the extreme heat is more effective at killing bacteria, therefore it can be argued that ultrapasteurized and UHT are safer to drink than milk pasteurized at lower temperatures. However, not all bacteria contained in milk is harmful and many of the cultures that thrive actually benefit the human digestive system. As heat treatment is unselective, these beneficial cultures are also destroyed. What ultrapasteurization does do, however, is greatly increase the amount of time milk can be stored, making it hugely advantageous for owners of small businesses who need to buy milk in bulk and store it safely for a period of time.
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