Pasteurization is a sanitation treatment that involves heating milk to a designated temperature over a period of time. This process accounts for milk's longer shelf life. Pasteurization makes milk last longer, allowing it to be shipped and sold prior to spoiling. Depending upon the type, milk lasts from a week to slightly over two weeks. Pasteurization allows this longer lifespan because it destroys some of the bacteria and enzymes responsible for the milk's rapid degradation.
Between 4 and 5 million pounds of milk are sold in the U.S. every month, according to the University of Wisconsin. This isn't a bad thing, especially as milk contains as many as nine key nutrients, according to the U.S. News. However, the wide-spread availability of the drink wouldn't have been possible without pasteurization, which mainly serves two purposes.
Milk Longevity and Quality
Outside of longevity, a more critical concern of pasteurization is milk safety. Although milk can be drank without pasteurization, it is far less safe than milk that has been pasteurized. The reason is bacteria, many of which naturally exist in milk and can harm humans.
Types of Pasteurization
Modern pasteurization comes in two forms, the continuous and batch types. The continuous method uses a plate heat exchanger and is much quicker than the batch heating method which involves a large heated vat. Because the vat doesn't separate the milk to the same degree as to the continuous method -- also known as high temperature short time method -- it takes much longer to perform the process.
Those who aren't familiar with the pasteurization process may be familiar with the name of the man who invented it, Louis Pasteur. Pasteur invented the process during the 19th century, mainly as a process for brewing beers. The process was born when Pasteur attempted to solve sugar fermentation issues during brewing. Eventually, his pasteurization techniques would evolve and be applied to milk, creating what people know as the pasteurization process today.
- Photo Credit Jupiterimages/Comstock/Getty Images