Is the milk you bought pure? These three numbers on the box reveal the secret

Review expert: Wang Guoyi, Postdoctoral Fellow in Nutrition and Food Safety, China Agricultural University

Milk is one of the most common foods in our daily life. It is rich in nutritional value and comes in many varieties.

However, after drinking milk for so many years, can you tell the difference between various milk products? What kind of milk can be called pure milk, and what is the difference between yogurt and yogurt drinks?

Source: pixabay

1

The Secret of the Milk Family

There are many names for milk on the market, the most common ones are fresh milk, pure milk, whole milk, high calcium milk, etc. However, according to the production process, milk is actually divided into only three types, namely pasteurized milk, sterilized milk and modified milk.

The "fresh milk" we often see is pasteurized milk, "pure milk" is sterilized milk, and other milk is generally formulated milk.

If you still can't tell the difference between the three, you can also check the "product standard number" starting with GB on the packaging box. The one ending with 645 is pasteurized milk, the one ending with 190 is sterilized milk, and the one ending with 191 is formulated milk.

Source: Screenshot of a Taobao product

So what is the difference between these three types of milk?

The main raw material of milk is raw milk, which needs to go through a series of processes before it becomes the milk we drink daily. The processing of raw milk includes sealing, homogenization, sterilization, cooling, canning and other steps. Among them, the difference between pasteurized milk and sterilized milk lies in the sterilization step.

In the sterilization step, pasteurized milk uses pasteurization, which is to heat raw milk at 62.8℃-65.6℃ for 30 minutes, or 72℃-75℃ for tens of seconds to achieve the sterilization effect. However, because this method still retains a small number of harmless or beneficial heat-resistant bacteria, fresh milk needs to be stored at 4℃, and its shelf life is not long, generally not more than 15 days.

Sterilized milk uses UHT sterilization, which means heating at 135℃~140℃ for 4-7 seconds to achieve a sterilization effect. This method can kill heat-resistant bacteria and create a sterile environment, so the shelf life of pure milk is longer, up to half a year.

The difference between formula milk and the above two types of milk lies in the ingredients. Fresh milk and pure milk only have one ingredient, "raw milk", while formula milk has much richer ingredients.

Source: A Taobao product introduction

Modulated milk is mainly divided into two categories. One is made by adding other ingredients to no less than 80% of raw cow's milk. For example, adding lactase makes it soothing milk; adding vitamin D, calcium, etc. makes it high-calcium milk. The other is reconstituted milk, which is an emulsion formed by concentrated milk, water, and milk powder. Wangzai Milk is a reconstituted milk .

In addition, skimmed milk, which is commonly seen in our diet, refers to milk made by removing the fat from raw cow's milk. Compared with whole milk, skimmed milk has a lower fat content, but because some fat-soluble vitamins in milk are removed during the skimming process, the nutritional content of skimmed milk is slightly inferior.

In addition to milk, yogurt is also very popular. Does it also have different types?

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Yogurt vs. Yogurt Drinks

Yogurt refers to a dairy product formed by direct fermentation of milk, including "flavored fermented milk" and "fermented milk".

Source: pixabay

The national food safety standard "GB 19302-2010 Fermented Milk" stipulates that the protein content of flavored fermented milk should be greater than 2.3%, the protein content of fermented milk should be greater than 2.9%, and the dairy product label must contain words such as "fermented milk", "yogurt", and "sour milk".

The main ingredient of yogurt is raw milk. Many common yogurt drinks, such as yogurt drinks, lactic acid drinks, lactic acid bacteria drinks, etc., usually have water as the first ingredient in the ingredient list, and the words "beverage" or "drink" are usually included in the name.

Lactic acid bacteria beverages are made from fresh milk or dairy products, fermented by lactic acid bacteria to make emulsion, and then mixed with water, white sugar, etc. The national standard "GB 10789-2015 General Rules for Beverages" stipulates that the protein content of lactic acid bacteria beverages must be greater than 0.7%.

Therefore, yogurt drinks are not real yogurt. Compared with yogurt, the nutritional content of the two is quite different.

Source: ingredient list of a certain product

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How to choose dairy products?

There are so many kinds of dairy products, how should we choose?

The "Dietary Guidelines for Chinese Residents (2022)" mentions that residents need to eat more of a variety of dairy products, and the daily intake should be approximately 300g to 500g.

From the perspective of nutritional value, fresh milk can retain the nutrients of milk to the greatest extent. However, during the ultra-high temperature sterilization process of pure milk, the natural active factors and flavor factors contained in the milk are lost to a certain extent. If you pay more attention to nutritional content and taste, you can give priority to fresh milk.

Source: Yang Huaigu, Zheng Nan, Wang Jiaqi. Comparative study on nutritional value and hygienic safety of pasteurized milk and ultra-high temperature sterilized milk. China Dairy Industry. 2016

For people who are lactose intolerant, fresh milk and pure milk are not suitable for drinking. They can choose yogurt instead.

When buying yogurt, you should also pay attention to choosing products named fermented milk or flavored fermented milk, and try to avoid yogurt drinks. The latter has lower protein and calcium content and higher sugar content; you can also check the product label and choose products with high protein content.

However, if you are trying to lose weight, it is recommended that you eat less yogurt, as flavored fermented milk contains a variety of auxiliary ingredients, such as jam and fruit particles, and has a high sugar content.

In general, as long as the dairy products are produced by regular manufacturers and comply with national regulations, we can buy them with confidence according to our own preferences. As one of the important sources of protein for the human body, dairy products also contain minerals, vitamins and other nutrients. For our health, everyone must insist on drinking enough milk every day.