Film preservation is one of the main food preservation methods, which is applied not only to eggs, but also to fruits, vegetables and meat products.
Fruit coating materials are mostly natural, non-toxic, harmless edible chitosan, fruit wax, animal oil, vegetable oil, etc., which are coated on the surface of the fruit by impregnation and spraying, which can achieve the purpose of preservation.
Food preservation is not only a method of coating preservation, but also commonly used methods such as controlled atmosphere storage and preservation, heat treatment preservation, low temperature storage and radiation preservation.
Modified atmosphere storage and preservation is to adjust the proportion of oxygen, nitrogen and carbon dioxide in the sealed package, so that the oxygen content in the sealed package is reduced and the carbon dioxide content is increased.
Reducing the oxygen content can effectively inhibit the reproduction of microorganisms and achieve the purpose of extending the shelf life.
Heat treatment and preservation are often used in the production of canned food, which is to heat the canned food to a certain temperature by purely physical means, so as to achieve the purpose of killing microorganisms.
Cryogenic storage includes both refrigeration and freezing, and this method is used to preserve food in refrigerators and freezers.
Low temperature can reduce the reproduction rate of microorganisms in food, and the reproduction ability of most microorganisms and spoilage bacteria is greatly weakened in an environment below 10 degrees Celsius.
When the temperature drops below zero degrees Celsius, the microorganisms have basically stopped breaking down the food; When the temperature drops to minus 10 degrees Celsius, most microorganisms will not survive.
Low temperatures can also reduce the activity of some enzymes in food and microorganisms.
In addition, there is also the radiation preservation method, which uses the radiation energy generated by radioactive elements to sterilize, insecticide and other treatments for fresh meat and its products, grains, fruits, vegetables, seasonings, etc., to extend the shelf life of food.