Milk is one of the most important foods for human consumption, since it is formed by a set of essential components for nutrition, including fat matrix, nitrogenous compounds, lactose, minerals, enzymes, vitamins, among others, all these nutrients besides being beneficial to humans, is also a nutrient broth for the development of microorganisms that cause fermentation.
In this sense, at the industrial level, different operations can be applied in pasteurization plants, with the purpose of increasing the capacity to preserve its nutritional and organoleptic properties in order to offer a hygienically acceptable product. Basically there are four processes applied, the first one being clarification, in which residues or impurities from the milking process are eliminated, such as remains of grass, insects, dirt from the cow's udder, among others, through filtering, and then centrifuging, which is capable of separating the solid impurities found there, during centrifuging, the fat particles of the milk can also be separated, and in this way standardize its content, thus obtaining the milk cream.
The next process is homogenization, which seeks to subject the fat particles to a mechanical treatment in order to break them and obtain a smaller size and mix them uniformly with the liquid fraction, in search of product stability. This is a thermophilic treatment, in which the temperature of the milk is raised to 60 to 75 °C for a very short period of time, in order to eliminate most of the microbiological flora present, but not 100%; this process can be done with a kettle or with a heat exchanger.
The last step in this process is sterilization, which, like pasteurization, is a thermophilic treatment; however, it seeks to eliminate as much microbial load as possible, in this process the milk is subjected to a temperature of 120 to 150 °C for approximately 20 minutes; this process is carried out with autoclaves or ultra-pasteurization equipment that allows obtaining milk with a long shelf life. The processes described above make it possible to preserve the product to be distributed in the market in a safer way from the sanitary point of view.
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