Milk is rich in protein, fat, vitamins, minerals and other nutrients, and milk protein contains essential amino acids. Milk fat is mostly short-chain and medium-chain fatty acids, which are easily absorbed by the human body; Potassium, phosphorus, calcium and other minerals have a reasonable proportion and are easily absorbed by the human body.
Sterilized milk: UHT milk is made by instantaneous sterilization at high temperature (120~ 140℃, 1~2sec). ) and can be stored for 30~40 days at room temperature. Traditional sterilized milk is a liquid dairy product made by high-temperature sterilization for a long time, which can be preserved for more than 6 months at room temperature. [2]
The contents of protein, lactose, minerals and other nutrients in sterilized fresh milk and sterilized milk are basically the same as those in raw milk, and only a small amount of B vitamins are lost, but the preservation rate of sterilized milk is usually above 90%, and the preservation rate of sterilized milk is above 60%, and the loss of vitamin C is great, but because it is not an important nutrient in milk, it has little effect on the nutritional value of dairy products. Commercially sterilized milk often fortifies vitamin A and vitamin D, making them the cheapest and most expensive of the two nutrients. [2]
"Raw milk", also called raw milk, is a common name for unsterilized and homogenized raw milk. At present, a small amount of "raw milk" is sold in bulk, and consumers usually boil it after buying it. The boxed and bagged prepackaged pure milk in the market is made of "raw milk" through cooling, raw milk inspection, impurity removal, standardization, homogenization and sterilization (pasteurization or ultra-high temperature sterilization), which is a product that meets the requirements of relevant national standards. Because it has not been homogenized, the milk fat globules of "raw milk" are large, which will gather and float after boiling, thus bringing the sensory impression of "sticky" and "rich flavor". However, the research shows that there is no significant difference in nutrition and human health function between "raw milk" and pasteurized pure milk.
The microbial contamination of raw milk is mainly caused by Escherichia coli, Staphylococcus aureus, Pseudomonas and fungi. In the environment, there are Brucella, Mycobacterium tuberculosis and other pathogenic bacteria from animals. Therefore, if "raw milk" is not fully sterilized, it will easily cause the spread of human and animal diseases. "Raw milk" has not undergone any disinfection treatment, so it is difficult to completely trace the information such as whether the cow is healthy, whether it was quarantined and polluted during transportation, and there are certain food safety hazards. Especially children, the elderly, pregnant women and people with low immunity are at greater risk of being infected with pathogenic bacteria after eating "raw milk". There are reports of food poisoning caused by eating "raw milk" at home and abroad. Therefore, consumers are advised not to drink raw milk directly.