Process of Pasteurization
Pasteurization, named after Louis Pasteur (1622-1895), its originator, was originally used to treat wine and beer, but soon came into use to treat milk as well, when it found that heating milk for a short time to below its boiling point killed microorganisms.
Pasteurization destroys 100 percent of pathogenic bacteria, yeasts and molds and 95 to 99 percent of other, nonpathogenic bacteria.
The process of pasteurization also inactivated many of the enzymes that cause the off-flavors of rancidity.
In the United States pasteurization was championed by Alice Catherine Evans (1881-1975), a microbiologists who worked for the US department of Agriculture.
Evans suffered from a disease known as brucellosis (undulant fever) and in 1918 she discovered that brucella, the bacterium that caused her disease, could be found in cow’s milk.
Scientists eventually determined that brucella was not the only milk borne bacterium. Milk can harbor other bacteria – such as E. coli, salmonella, and listeria – which can cause harmful and even life threatening infectious in the young, the old, pregnant women and the infirm.
Indeed, unpasteurized cow’s milk was a very common cause of tuberculosis, typhoid fever and salmonellosis.
Evans advocated on behalf of pasteurization for years after her discovery. Finally in the 1930s, milk pasteurization became mandatory under US law.
The advantages to be derived from pasteurization vary with the conditions under which the milk is produced and the efficiency with which the work is conducted.
If the milk comes from dairies where disease and uncleanliness prevail, pasteurization will prolong the keeping quality of the milk and also materially lessen the danger from disease germs.
If on the other hand, healthfulness and cleanliness receive the exacting attention which prevails on certified dairy farms, nothing can be gained by subjected milk to the pasteurizing process.
Process of Pasteurization
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