1. Before adding food preservatives, it should be ensured that the food is completely sterilized and there should not be a large number of organisms, otherwise the addition of preservatives will not have an ideal effect. For example, potassium sorbate will not play an anti-corrosion role, but will become a nutrient source for microbial reproduction.

2. The toxicity and application range of various preservatives should be understood, and they should be added according to the safe use amount and application range. For example, sodium benzoate, because of its strong toxicity, has been banned in some countries, and China is also strictly uncertain that it can only be used in sauces, jams, pickles, cans and some wines.

3. It is necessary to know the effective use environment of all kinds of preservatives. Acid preservatives can only be used in acid environment with strong and effective anticorrosion effect, but not in neutral or alkalescent environment, such as potassium sorbate, sodium benzoate, etc.; while Nipagin Esters in ester preservatives can also be used between ph4-8 with good effect.

4. It is necessary to know the types of microorganisms that can be inhibited by various preservatives. Some preservatives have effects on mold and some on yeast. Only by mastering the characteristics of preservatives, can drugs be applied to the case. Generally, there are many products that have been compounded to carry out comprehensive anti-corrosion and preservation, such as Jianying anti-corruption king and anti mildew preservatives.

5. According to different kinds of food processing technology, we should consider the price and solubility of preservatives, as well as the impact on food flavor and other factors, and then use them flexibly.