Food preservatives play a key role in ensuring the freshness and safety of food. China recognizes a rich variety of food preservatives, including benzoic acid and its sodium salt, sorbic acid and its potassium salt, calcium propionate and so on*** 25 kinds. The mechanism of action of these preservatives is to continuously inhibit the growth of microorganisms, especially when conventional sterilization measures are insufficient, but still effective in preventing food spoilage.

For preservation needs in non-food areas, such as wood and fiber protection, mineral oil, coal tar, tannin and so on will be used. And in biological specimen preservation, formaldehyde, ascending mercury and toluene are also commonly used preservatives. However, considering food health, the food industry prefers to use physical methods, such as drying and curing, rather than relying too much on chemical preservatives.

It is worth mentioning that there are also specific preservatives, such as organic acids (e.g. acetic acid), vegetable oils (with oleic acid lipids as the main ingredient), and special essential oils (e.g. mustard oil), which are also used in food under specific conditions. And in the localized areas of the body, such as the skin or the digestive tract, iodoform, phenyl salicylate, aniline dyes or acridine pigments are chosen as preservatives to ensure local health and safety.