Ways to extend the shelf life:
1, hot filling sterilization method is more suitable. The technical tips are as follows: after the soup is boiled, put it in a cup and seal it while it is hot, then put it in boiling water and cool it. This is canned food.
2. According to the method of 1, it can be stored for a long time, more than 7 days.
3, it is recommended not to think about this, the current food tends to be healthy food. Besides, since you are a restaurant, there is no need to take 10 something that won't rot.
Preservatives are not recommended. Without preservatives, you will be more popular. I suggest; First of all, thoroughly disinfect the packaged utensils, make a sterile and dust-free packaging room, and all props pass through the window to minimize external pollution. After packaging at a suitable temperature, let the temperature drop to room temperature as soon as possible (don't freeze it quickly, it will affect the quality, you can blow it with cold air), and finally put it in the refrigerator (cold storage) at 0-4 degrees (neither too low nor too high). Here we need to pay attention to the order of goods in and out to avoid excessive temperature fluctuation. In this environment, it is no problem to keep the product for three or four days (I personally suggest that it should not exceed four days, because your highly nutritious food is easy to go bad, and I don't think knowledgeable people will drink it for more than four days. For everyone's good, I suggest that it should not exceed four days). After you sell it to others, let them keep it in the refrigerator. As far as I know, your products taste better after freezing.
There is also that you supply the school, you can go to the school and ask the food professional teacher.