What Are Milk Ducts?

Fresh milk refers to the milk within 24 hours of being separated from the cow's body, otherwise it cannot be called "fresh" milk. Originally, the country had explicit regulations on "fresh milk" in the milk industry, so dairy companies could not mention the word "fresh" in their products. Liquid milk is available at room temperature and low temperature fresh milk.

Fresh milk

Fresh milk is consumed mainly by cows, buffaloes and sheep, as well as horses. According to the traditional production method, after the fresh milk is squeezed out, it is transported from the ranch to the processing plant. There are several links in the middle: the small tanks of the milk producers are poured into the large tanks (barrels) of the acquirers and then transported to the milk processing plants. In a stainless steel refrigerated tank, cool the milk to below 10 ° C in about an hour. This decentralized collection is prone to quality problems. If a jar of spoiled milk is poured into a large jar, it will affect the quality of the whole jar. Therefore, it is very important to strengthen the quality inspection and timely clean and disinfect large and small tanks and buckets. The deterioration of fresh milk is mostly caused by the proliferation of bacteria. It may also deteriorate due to protein breakdown or fat oxidation. Raw milk contains a lot of bacteria. According to statistics, the milk in the cow's body contains more than 500 bacteria per milliliter, and when the number of bacteria per milliliter of milk increases to 107, the milk shows obvious spoilage and deterioration. Therefore, the key to controlling the quality of fresh milk lies in timely cooling and sterilization, strengthening the disinfection of the container and preventing secondary pollution.

Fresh milk is a good medium for microorganisms, in which the water content is large, the pH value is close to neutral, the content of fat, protein and lactose is high, which is rich in nutritional value. Fresh milk produced between April and June each year has a low fat content, while fresh milk produced between November and January has the highest fat content. In contrast, fresh milk produced between April and June has the highest solid non-fat content, and fresh milk produced between November and January has the lowest solid non-fat content. Fats in milk are more difficult to destroy than ingredients such as protein and carbohydrates. However, fat itself is susceptible to deterioration such as oxidation. Most bacteria are most active in the temperature range of 10 30 . The lower temperature to limit bacterial activation in fresh milk is 0 ° C to 1 ° C, and the maximum temperature to completely limit bacterial growth is 70 ° C. Therefore, fresh milk should be cooled to below 10 ° C in time after collection and during the sales process in order to inhibit the proliferation of bacteria during this time. 1.2 Pasteurization of fresh milk For sale of fresh milk for drinking, it must be pasteurized. The purpose is to kill the bacteria in the milk to ensure its quality. Sterilization should not affect the original taste, appearance, and nutritional value of fresh milk, and the temperature should not be high. In addition, through sterilization, it can also destroy those microorganisms that easily cause deterioration of fresh milk.

There are two types of liquid milk: normal-temperature milk and low-temperature fresh-keeping milk. Low temperature fresh milk, usually refers to milk pasteurized and homogenized with raw milk, also known as

According to years of research by domestic and foreign milk nutrition experts, drinking a glass of fresh milk every day has at least 13 benefits for the human body.

1. Potassium in milk can stabilize arterial blood vessels under high pressure and reduce the risk of stroke;

2. Milk prevents the body from absorbing the toxic metals lead and cadmium in food;

3. Yogurt and fat can enhance the function of the immune system and prevent tumor cells from growing;

4. Iron, copper and lecithin in milk can greatly improve the working efficiency of the brain;

5. Calcium in milk can strengthen bones and teeth and reduce the occurrence of bone diseases;

6. Iron, copper and vitamin A in milk have a cosmetic effect;

7. Tyrosine in milk can promote the massive growth of the hormone serotonin;

8. Magnesium in milk makes the heart resistant to fatigue;

9. Zinc in milk can make wounds heal faster;

10. Vitamin B in milk improves vision;

11. Drinking milk can prevent arteriosclerosis;

12. Milk is high in calcium and well absorbed;

13. Drinking milk before bed can help you sleep.

People often say that fresh milk is actually low-temperature fresh-keeping milk made by pasteurization, that is, pasteurized milk. Drinking fresh milk can supplement the body's protein, fat and calcium.

Because fresh milk uses a low-temperature sterilization method, compared to normal temperature milk, it has a richer taste, which is also an important reason why people choose to drink fresh milk. The opposite of fresh milk is normal temperature milk made by high temperature sterilization technology. Many people think that ultra high temperature sterilized normal temperature milk will lose many nutrients, but it is not.

The main purpose of drinking milk is to supplement protein, calcium and other vitamins. Milk is rich in nutrients, but the four most important are lysine (an amino acid), calcium, vitamin B2 (riboflavin), and vitamin B12, although there will be some in the ultra-high temperature sterilization process. The ingredients are inactive, but they have not reduced the nutrition in the milk.

First of all, the protein in milk will undergo denaturation after technical processing, which is a physical change, but the denaturation of protein has no effect on its nutritional value. Secondly, the calcium in milk does not affect the absorption and utilization of it by the human body. Finally, the ultra-high temperature disinfection of milk does destroy some heat-sensitive vitamins, but the damage is very low. In addition to vitamin B2 and vitamin B12 in milk, other humans need lower levels of vitamins, and most of the vitamins are obtained through vegetables and fruits.

The main nutritional components of fresh milk are not significantly different from normal temperature milk. Compared with normal temperature milk, fresh milk has no difference in absorption rate of calcium, the effect of calcium on bone density, or the efficacy of protein.

Many people have noticed that the packaging of fresh milk is relatively simple, the product has a short shelf life, and a cold chain system is required during transportation. Fresh milk has strict requirements for storage conditions, which can easily lead to spoilage and make it impossible to drink. So if you buy fresh milk, you must pay attention to drinking in time.

The method to test whether the sterilization is thorough is that the milk is first cultured with disodium phenyl phosphate, and then mixed with 2,6 dichloroquinone-chloroimine. If the milk appears blue, it may indicate insufficient pasteurization or the milk is contaminated. 1.3 Packaging of fresh milk After pasteurization, fresh milk is usually filled in glass bottles and delivered to consumers. Glass bottles are used repeatedly. The recovered glass bottles are taken by "immersion" or "spraying" and washed by a bottle washer.

After the first test wash, the bottle is rinsed with one or two hot washing solutions, and then washed with warm water. Washed bottles are generally not specially sterilized and sterilized. A more complete bottle washing machine also includes a disinfection process in the washing process. The filling of fresh milk is automated. After filling the bottle from the filling funnel, the bottle is immediately sealed with aluminum foil to prevent secondary pollution.

Wax paper or wax-impregnated cardboard cover is widely used in China, and its effect is not as good as aluminum foil cover. Fresh milk can also be packed in composite cartons, such as

September 1986 "Standards for the Acquisition of Fresh Milk" issued by the former National Bureau of Standards

It is clearly stipulated in the regulations that raw milk refers to colostrum extruded from the breasts of healthy cows that are normally raised and free of infectious diseases and mastitis. In 2003, the "Sanitary Standards for Fresh Milk" issued by the Ministry of Health and the National Standardization Management Committee further stated that the secretions extruded from the breasts of cattle (sheep) were free of food additives and no ingredients were extracted from them. "Fresh" means fresh, without any processing. Because raw milk that has not undergone thermal processing is contaminated with microorganisms (bacteria) within a short period of time. It will endanger human health after drinking. Therefore, as early as the early 1980s, the "Milk and Milk Hygiene Management Measures" promulgated by the Ministry of Health clearly stated that raw milk is prohibited from being marketed. In other words, no fresh milk is found on the market.