Abstract

                                A single drop of milk may contain on an average about a lakh of bacteria, as sold by vendors in the Coimbatore town. Milk is a very good medium for the growth and multiplication of almost all kinds of bacteria, good, bad and indifferent. Some bacteria such as those that produce curds, cheese etc., are beneficial and useful; there are a great many different kinds of bacteria which may be termed indifferent as they are not useful in any particular manner and at the same time do no harm in any way by their presence and growth in milk. But there is the third class which is positively harmful. Bacteria producing tuberculosis, diphtheria, typhoid, cholera, etc., grow luxuriantly in milk once they find their way in. A noted dairy scientist, Dr. Orla Jensen, claims that in parts of Europe, repeated epidemics of typhoid and cholera have been caused by infected milk. In a hot country like India especially, where milk remains at a high temperature, the bacteria tend to develop most marvellously, a single individual dividing into two within twenty minutes. Hence the need for clean milk containing as few bacteria as possible and no harmful bacteria at all. Even while in the udder, milk contains a few organisms mostly of the beneficial and indifferent kinds except in cases where the cow itself is diseased. The large numbers obtained in milk samples are most often due to outside contamination, e.g.. from air and water, unclean vessels and the unclean person of the milker. Therefore, if outside contamination is limited to the minimum, it will be possible to obtain milk which would contain very few organisms indeed. Thus the Government Dairy at Coimbatore by virtue of its being clean, is able to produce milk which contains only about one thousand bacteria in a drop, whereas milk produced by vendors contain about a hundred thousand bacteria in the same quantity.

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