Monday, January 12, 2009


All recognize that milk is a protective food, especially for non-meat eating population, children and women, due its unique nutrient make up, containing almost all nourishing factors necessary for survival and growth. The ability of a new born baby to survive and grow exclusively on mother's milk is proof enough, if it is needed, regarding the virtues of milk as a food. Before the advent of pasteurization by heat in the 19th century, people were consuming raw fresh milk without even heating at home under the impression that heat would destroy nutrients making milk less nutritious. Discovery that heat can kill pathogenic microorganisms opened up a new vista for commercialization of milk through organized dairy ventures. True to the old saying that 'necessity is the mother of invention', heat processing, developed for milk preservation, was based on Louis Pasteur's discovery of the technique of destroying pathogens by heat to meet the needs of people settled away from the milk sources. Thus was borne the process of milk pasteurization as we know to day which involves treatment at 63C for 30 minutes or its equivalent to ensure complete destruction of the pathogens. The heat process also helps to delay the action of lactic acid bacteria which otherwise lowers the pH creating problems for boiling milk at home.

Some people do not accept the large scale deployment of pasteurization technology for milk because of their strong conviction that this process reduces the natural nutritive value by destroying the beneficial factors the are present in milk. They even argue that if a tender child can consume mothers' milk without processing, why others cannot consume animal milk also without any processing. They further surmise that pasteurization is used by the industry to mask the defects in milk already spoiled!. Raw milk advocates further claim that unpasteurized milk prevents and cures many disease, though there is hardly any evidence to substantiate such claims. Present level of knowledge cannot support such a view completely, though there may be marginal loss of some of the heat labile nutrients which is inevitable. The way Indians 'cook' the milk may be of much more concern than what the relatively mild pasteurization temperatures can do to the nutritional quality of milk.

It is difficult to believe that any one drinks milk directly and immediately after milking, even in rural areas where milch cattle are mostly raised. The revolutionary "Milk Cooker", an Indian designed gadget is a priced possession of every house hold and it goes to show that boiling of milk is a routine operation. Indians have a marked preference for boiled milk due to the mild caramelized taste, heating imparts to the heated product. This is further corroborated by the failure of cold milk to establish as a credible beverage in the country to any large extent. In contrast consumers in the West are tuned to UHT milk in cartons and plastic containers and direct consumption as hot milk is very limited. Tetra pack milk now available in the country is not patronized to any great extent as the cost factor, darker color and need to refrigerate once opened, make it an unattractive consumer option. The myth that milk is pasteurized or sterilized to convert bad milk to good milk cannot be allowed to linger in the minds of consumers as heat treatment is a 'must' process, if milk is not to become a carrier of diseases rather than a treasure house of nutrients. Food technology does not encourage making good looking food from an intrinsically bad one, a misconception prevalent amongst many consumers, especially conservative minded people.

India produces over 100 million tons of fluid milk annually which get distributed to over a billion people from the point of production and more than 60% undergo pasteurization before reaching the consumer. But for the chilling and pasteurization processes a major portion would have been wasted. It is known that even a couple of hours delay in chilling can multiply bacteria naturally present as well as through cross contamination to unacceptable levels. In many countries sale of unpasteurized milk is banned so as to prevent out break of of milk mediated diseases. While pathogens can pose a grave threat, old milk is not suitable for boiling as even a small increase in acidity due to bacteria can cause breaking of the milk making it unfit for consumption in any mode. The relatively primitive environment that exists in the cattle rearing areas and unsatisfactory personal hygienic habits of those engaged in milking, make it inevitable for the milk to carry high microbial loads with distinct possibility of presence of pathogens like Salmonella, E.coli, Mycobacterium tuberculosis, Coxiella burnetii, etc. Chilling and Pasteurization are God-sent answer to less affluent countries like India to save their precious resources.


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