Current location - Health Preservation Learning Network - Slimming men and women - How long is the shelf life of yogurt?
How long is the shelf life of yogurt?
The shelf life of yogurt is generally short, but how long is it? Let me sort out the information about how long the shelf life of yogurt is. I hope you like it! How long is the shelf life of yogurt? Keep it at 2-6 degrees. The shelf life of pure yogurt is generally about 15 days. If you want to put it in a normal temperature environment, you have to consider the season. If it is summer, the shelf life of yogurt is correspondingly shorter. The temperature is about 30 degrees, and the shelf life is only two or three days at most, or even shorter. Deteriorated milk, of course, can't be drunk, it will have diarrhea. But it can be used to water flowers. Deteriorated yogurt has a sour taste. Generally speaking, the upper layer is blocky or cauliflower-like, and the lower layer is watery or oily. Yogurt without deterioration is the same, creamy, sweet and sour. How to preserve yogurt at room temperature is also called "sterilized yogurt". Compared with low-temperature yogurt ("live bacteria yogurt"), it is fermented by lactic acid bacteria and then heat-treated again to kill the live lactic acid bacteria in yogurt, so it can be sold and stored at room temperature. From the point of view of nutrition, the biggest difference between low-temperature yogurt and normal-temperature yogurt is whether it contains "live lactic acid bacteria", and there is no difference in other nutrients. If drinking yogurt is to get the benefits of lactic acid bacteria, then it is recommended to choose yogurt with live bacteria at low temperature. If you don't need live bacteria, room temperature yogurt has more market advantages. Because even without lactic acid bacteria, there are still protein, calcium and vitamins in yogurt. For people (such as students or people traveling abroad) who cannot be refrigerated due to various conditions, room temperature yogurt is a better choice. There is also low-temperature yogurt: it should be reminded that low-temperature yogurt cannot be sold at room temperature, but it can be sold in a low-temperature cabinet. After cold storage, the taste of normal-temperature yogurt will be closer to that of low-temperature yogurt, which is also the main strategy for many imported normal-temperature yogurt to be sold in China. So when you buy yogurt, you should check the label of yogurt, whether it is "live bacteria type" or "sterilized type"; You can also check the shelf life. Generally, the shelf life is between 3 months and 6 months, and the shelf life is less than one month, which is generally low-temperature yogurt. I believe that there are many friends who love to drink yogurt, but if you buy too much at a time, improper preservation methods may make yogurt go bad. So how should such a situation be avoided? I am about to introduce to you: the preservation method of yogurt and how to keep yogurt from going bad. One method (1) is to add 70kg sucrose and 10kg glucose to 100kg skim milk (milk fat content is lower than 3%), then homogenize under the pressure of 20MPa, then heat to 98℃, keep the temperature for 2.5min, and sterilize. After sterilization, it was quickly cooled to 30℃, then 0.25kgIST starter was added and stirred evenly, and fermented at this temperature. When the pH value reaches 4.2, the fermentation is stopped, which is the curd yogurt. When the yogurt prepared by the above method is cooled to 15℃, food-grade citric acid is added to adjust the pH value to 4. 1, then the mixture is stirred, and 29kg of orange pectin solution and 3.5kg of orange essence are added. The preparation method of citrus pectin solution is as follows: 2.2 kg of citrus pectin is added to 27 kg of water and stirred evenly. It is best to homogenize the above mixture with colloid mill at 20MPa and then heat it to 565,438 0℃. In the whole process, pay attention to the temperature difference between the heating medium and the material should not be higher than 5℃. When the temperature reaches 5 1℃, check the temperature quickly and accurately. And let it cool to 32℃, pay attention to the temperature difference between the cooling medium and the material should not be higher than 5℃. When the material is cooled to 32℃, it is homogenized again under the pressure of 20MPa, and then heated to 90℃ for 30s. Pay attention to continuous stirring during heating and holding. In addition, during heating sterilization, the temperature difference between the heating medium and the material should not exceed 5℃. Finally, the sterilized materials are cooled to 22℃ and packaged under aseptic conditions at this temperature to obtain the final product. At this time, the number of bacteria was detected, and the result was 90 /mL. If this product is stored at room temperature, there will be no whey precipitation and flavor deterioration after 6 months. (2) In the second method, all the operations in 1 are repeated, but the control parameters need to be slightly changed, that is, when the material is heated to 90℃ and sterilized for 30s, the cooling temperature is changed from 22℃ to 30℃, and packaging is carried out at this temperature. The product was stored at 65438 05℃ for 6 months, and there were still no quality accidents such as whey precipitation and flavor deterioration. (3) The third method repeats the operation of the first method, but sugar and fruit essence are not added in the formula. After aseptic packaging, the bacterial count of the product prepared according to the above formula is 92 /mL. After storage for 6 months, there is no separation and precipitation of whey, and its flavor is like fresh products. (4) Method 4 repeats the production operation of method 1, but changes the following process parameters. One is to change orange essence into raspberry essence (also called raspberry). Secondly, when the temperature rises to 565,438+0℃, the temperature difference between the heating medium and the cooling medium and the material is 8℃, which decreases from 565,438+0℃ to 32℃. The products made according to this process and formula have no whey precipitation and precipitation, and the flavor has not changed after being stored at room temperature for 6 months. (5) The production process of the fifth method remains unchanged, but after the last homogenization, the materials are put into glass bottles and then sterilized at 90℃ for 30s. Finally, cooling to room temperature to obtain the product. The product prepared by this method is stored at room temperature for 6 months, and the flavor of the product remains unchanged, and there are no quality accidents such as whey precipitation and precipitation.