Why Is Milk Pasteurized ?
- In pursuit of getting the better of disease and bodily suffering, biologists and scientists over the last few centuries have made some very important inventions and discoveries to the benefit of mankind. Of all the medical discoveries like the cell theory, penicillin, anesthesia, structure of DNA etc, the establishing of germ theory by a French microbiologist Louis Pasteur is widely accepted as the most significant one for the good of humanity.
- Louis pasteur discovered that most infectious diseases are caused by microbes (microorganisms) overwhelmingly present in and around us, which he termed ‘Germs’. His attempt at detecting such life forms, which contaminated consumable liquids (beers, wines milk etc.) making them unpalatable, led him to look for a method to identify and destroy the bacteria responsible for spoiling beverages. He observed that certain environmental conditions were necessary for these harmful microbes (also called bacteria), to germinate, multiply and contaminate beverages making them unfit for human consumption. And that these very bacteria could be eliminated with heat treatment under controlled conditions.
- Milk being one of our most nutritionally complete food, rich in high quality proteins, fat, milk sugar, essential minerals and vitamins, was an obvious target liquid food to be saved from contamination, more so because of its vehement presence in worldwide cuisines. It may be worth mentioning here that before Pasteur, Robert Koch had already identified mycobacterium tuberculosis, the TB causing bacteria in milk. Discovery of this and more such disease causing pathogens added to the need to banish unhealthy part out of healthy drinks.
- Milk is generally known to contain some beneficial and some harmless bacteria, but the contaminating bacteria make their way into milk or the milk giving animals through improper handling, major factors being; changes in health status of milch animals or the handlers and entry of contaminants (microorganisms) from polluted water, dirt, manure, vermin etc., which are abundantly present in the immediate environment around us. These microbes find their way to the hair, udder and teats of the dairy animals, which finally move up the teat canal, without showing any disease symptoms in the dairy animals. Apart from intrusion of harmful microbes into dairy animals’ bodies, they also gain access into raw milk during its transportation and storage, thus unknowingly contaminating it.
- Keeping in view the importance of milk in human diet, it became all the more crucial to safeguard milk from contaminants and ensure healthy usage of the liquid for all times to come. The process of sterilization which was already in practice for various other disinfecting needs, was the initially thought of idea to purge milk of harmful bacteria that it developed during handling and storage. Sterilization, though a proven method to eradicate harmful pathogens had an adverse aspect attached to it; that it would eliminate the nourishing friendly microorganisms too. This led Louis Pasteur into pioneering the concept of heat treatment of milk, as also of other drinkable liquids. In this process, which came to be christened as ‘pasteurization‘, milk would be heated only to a certain degree of temperature, good enough to eliminate the targeted group of harmful bacteria. This controlled heat treatment would rid the milk of harmful microorganisms by either eradicating them or nullifying chances of their growth. A big advantage of this process was that the beneficial bacteria in milk, immune to temperatures that would kill harmful pathogens, remained unaffected and kept the liquid healthy as desired.
- Thus pasteurization not only frees milk of unhealthy bacteria for human consumption, it also invariably increases the shelf life of milk enabling transportation to far off places for consumption of all and sundry.
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