If the preservative film is breathable, it will not be good in fresh-keeping. There are strict control indicators in the regulations of the breathability PE preservative film according to the national standard. Here there are problems of breathability and tensile?strength facing us. For example, the oxygen permeability is stipulated within the range of 7000-20000, while the water permeability is required to be as less as possible.
Preservative film principle: 1. 1. Prevent water evaporation, and play the function of sealing; 2. Prevent loss of the original flavor of food in storage; 3. Isolate air, and prevent food oxidation (or infection); if you want to do the experiment of this kind, it is best to choose the anaerobic bacteria, and you should pay attention to the seal degree to prevent leakage. You should also be attentive of the type of the chosen food, and note whether it is suitable for the growing conditions of the chosen bacteria and pay attention to the temperature, humidity, shaking table rate, etc.
It is not breathable. Plastic wrap principle: 1. Prevent water evaporation, and play the function of sealing; 2. Prevent loss of the original flavor of food in storage; 3. Isolate air, and prevent food oxidation (or infection).
