Source of Bacteria in Milk

Source of Bacteria in Milk
Some bacteria are normally present in the udder of the cow, and these may contribute to the bacterial flora of the milk. However, unless the udder is infected, it is not considered to be an important source of such microorganisms. 

Other sources of microbial contaminations of milk are the body of the cow, milking machines and other equipment and utensils, the air in the milking barn, and the hands, nose, and throat of those attending to the milking process. In the handling of milk upon delivery to the processing plant or dairy, further sources of contamination may be encountered.

In order to limit the number of bacteria present in raw milk, certain precautionary procedures are ordinarily applied. The flanks, udder, and teats of the cow should be washed, treated with a sanitizing solution, and dried before milk is drawn. 

Large dairy farms often have a special wash pen for cows to be milk. Utensils, including the milking machine, should be cleansed and disinfected either with live steam or with a solution of chlorine (about 200 ppm of available chlorine). 

Bulk milk tanks may be cleaned manually with detergent and water at about 130 F , the sanitized with chlorine solution, or cleaned mechanically with detergent and water at 150 F, and finally sanitized with chlorine solution. Outlet valves and the outside of the tanks must be cleaned and sanitized manually. Cleaning in place (CIP) may be used to clean, sanitized, and rinse the pipe line and the bulk milk line tank of a vacuum or pressure system is available.
Source of Bacteria in Milk