Someone asked, is the production date in yogurt related to the number of probiotics? I used to hear that buying yogurt is the closer to the production date, the better. Is this because the yogurt is stored for a long time and there will be few probiotics?
Probiotics are beneficial to health, and there is not much clinical evidence
100 years ago, Russian immunologist Mekonikov noticed that farmers in Bulgaria are healthier and longer. He attributed the reason to the fact that the fermented milk they consumed contains live bacteria, and the concept of probiotics emerged. Since then, scientists have gradually recognized this concept, believing that supplementing sufficient number and appropriate species of live bacteria can help humans enhance immunity and resist bacterial infections.
Probiotics are just a concept similar to "good people". There are countless bacteria that can be called probiotics, and each one is different. The function of probiotics must be achieved by specific strains, specific doses, continuous consumption, and live bacteria. Many commercial propaganda say "study shows what functions are probiotics" and lists the functions mentioned in a large number of literature. However, these functions may have nothing to do with their bacteria. There are also many advertising and sales promotions that claim that "the content of bacteria is as high as a lot", but the dosages that can produce effects vary greatly. Some eat 100 million yuan a day to work, while others require 1 trillion yuan.
Although yogurt marketing often "heavy books and colors" probiotics, there is actually no need to use it as a reason for eating yogurt - how much effect can the probiotics in it play? It mainly depends on speculation, and the real clinical evidence is not that rich. And milk itself is the key to nutrition - the most important nutrients in milk, protein and calcium, are still the same, and many lactose are converted into lactic acid, making people who are intolerant of lactose can also eat dairy products. In addition, bacterial fermentation may also produce some vitamins and other small molecule metabolites, which may also have certain health benefits.
The shelf life of yogurt is measured by its flavor and taste. Most foods have shelf life. However, changes in food during preservation occur continuously, and the shelf life is a time that is artificially selected. This means that the manufacturer guarantees that all food indicators will meet the manufacturer's commitments within this period.
The "indicators" of different foods are different. For yogurt, flavor, taste, number of live lactic acid bacteria, and number of pathogenic bacteria are the most important indicators, and flavor and taste are closely related to changes in bacteria.
Whether it is lactic acid bacteria or other bacteria, their growth follows a similar trajectory. At first there will be a period of stagnation and growth, then it will proliferate rapidly, and finally die in large quantities. Different bacteria, different starting content, different temperatures and other environmental conditions will have a very different time at different stages.
In yogurt, lactic acid bacteria have an absolute advantage. There were not many miscellaneous bacteria, yeast, molds, etc. that we didn’t like at the beginning. At refrigeration temperature, lactic acid bacteria will have a hysteresis growth period of several days. After a few days, the number of lactic acid bacteria will increase, and more lactose will be converted into lactic acid, and a layer of light yellow liquid, i.e. whey will appear in the yogurt. At this time, the flavor and taste of yogurt will change, but the yogurt itself can still be eaten. If it is stored for a longer time, the lactic acid bacteria will be reduced in large quantities and the mixed bacteria will become active. The activity of the mixed bacteria will produce a bad flavor and the appearance of the yogurt will further deteriorate. The yogurt at this time is not only not delicious, but also safety is a problem.
Buy less yogurt every time, buy
After eating it as soon as possible 0If the yogurt is placed at room temperature, the process will be greatly accelerated. At the fresh-keeping temperature, the time scale of this process can be measured in "days", while at room temperature, it needs to be calculated in "hours". Because the changes in flavor taste occur before the decrease of live bacteria and the increase of miscellaneous bacteria, the shelf life of yogurt is measured by the changes in flavor taste. As ordinary consumers, we cannot know what the bacteria in it have grown, but the flavors are distinguishable - so whether it is placed in the refrigerator or at room temperature, if there is no odor, the appearance and taste have not become very bad, and it can be eaten.
Yogurt is a good dairy product.This "good" is not because of the so-called probiotics, it emphasizes that it is just a marketing selling point for merchants. For consumers, there is no need to worry about how many live bacteria are left behind - even during the shelf life, you should buy less yogurt every time, and it is better to buy it after eating it as soon as possible.
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