Machine Principle Application
DATE:2016-06-29 09:13HITS:105次
Within a certain temperature range, the lower the temperature, the slower bacterial growth; the higher the temperature, the faster reproduction. But the temperature is too high, the bacteria will die. Different bacteria have different optimum growth temperature and heat resistance, cold ability. Pasteurization is actually not very heat-resistant pathogens utilizing the characteristics of treatment with the appropriate temperature and time, kill them all. However, after pasteurization, still retains a small part of the harmless or beneficial, the more resistant bacteria or bacterial spores, so pasteurized milk to be stored at a temperature of about 4 ℃, and can only be stored for 3 to 10 days, up to 16 days.
As a milk sterilization, can kill pathogens harmful to health but also make less milk quality possible changes occur. One kind is based on the extremely high temperature TB thermal death curve and milk quality is the most susceptible to heat cream separation principle difference thermal damage curve, at a low temperature for a long time or a short time at a high temperature heat treatment method. Wherein, in the following 60 ℃ heated for 30 minutes the way, as a standard low-temperature sterilization, as early as the world's widely used. High temperature treatment, although somewhat on milk quality, but can enhance the sterilization effect, this method is called high-temperature sterilization (sterilization), which is heated above 95 ℃ 20 minutes. In addition to pasteurization of milk, it can also be applied fermented products, vacuum packaged food sterilization.
Typically, the bags of milk on the market is the use of pasteurization produced. Factory taken to fresh milk, the first low-temperature process, then sterilized by pasteurization. Bags produced by this method is usually milk can be stored for a long time. Of course, the specific processes and process much more complex, but the general principle is this.
It should be noted that drinking fresh milk (mean just will milk) but is unsafe because it may contain harmful bacteria in our bodies. Another point is that pasteurization is not a panacea, milk after pasteurization still be stored at low temperatures (generally <4 ℃), otherwise there is still the possibility of deterioration. So many ways to market to sell bags of milk is very specifications.
Pasteurized milk is the world's largest consumer of milk varieties, the consumption of the United Kingdom, Australia, the United States, Canada and other countries are pasteurized milk accounted for more than 80% of liquid milk, varieties whole skimmed, semi-skimmed or full fat. In the US market, actually almost all pasteurized milk, and a large package (1 L, 2 L, 1 gallon), and the public once the supermarket to buy enough one week to drink milk. Few sterilized milk market to sell, and some small towns simply can not buy.
Pasteurized pure milk nutrition and well preserved natural flavor of milk, milk in all varieties is the best kind. In fact, if pasteurized milk at a temperature of about 4 ℃ preservation, propagation of bacteria is very slow, nutrition and flavor of milk can be kept constant within a few days.
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