5 Jan 2012



Bacteria are contaminants of all fresh foods. In order to avoid excessive spoilage, various measures can be employed to kill bacteria or to retard bacterial growth. These include keeping foods cold (or frozen), boiling (as is done for canned foods), salting (pickling), dehydrating (as in beef jerky), and adding anti-bacterial preservatives. In the particular case of milk, pasteurization combined with refrigeration is the most common technique used. Pasteurization does not kill all the bacteria (or spores) in milk, but does eliminate most of the pathogenic bacteria that have been historically associated with milk, such as tuberculosis, brucellosis, and typhoid. Pasteurization was first developed in order to kill these pathogens, but it was soon discovered that this process also improved the keeping quality of the milk without sacrificing the taste. Pasteurization can be accomplished by heating milk to 63-650 C for 30 minutes or to 71° c for 15 seconds (flash pasteurization) followed by rapid cooling. Flash pasteurization is the most common technique used. Pasteurization does not prevent spoilage, but it reduces the bacterial population so that spoilage occurs more slowly. Milk can be essentially sterilized by Ultra High Temperature (UHT) pasteurization in which it is heated to a higher temperature than is used for normal pasteurization, but just for a few seconds (149° C for 6 to 9 seconds). This milk can be stored for several months at room temperature without spoiling. There are a variety of bacteria that can be present in raw milk due to improper Collection preservation and  maintenance .

From the results  data it was  observed  that the  good hygienic  conditions  maintained  during  collection of  milk will minimize the  microbial colony count
And the  Lipolytic  activity of the  bacteria.

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