What are the natural preservatives?

As we all know, artificial preservatives must be used in a certain amount, once excessive, it will cause harm to human body Is there any natural preservative in this world? Food preservatives can be divided into natural preservatives and synthetic preservatives according to different sources Due to the high cost of natural preservatives, they have not been widely used in food processing for a long time, while some artificial preservatives have been widely used in food processing because of their low price and good antiseptic effect However, some synthetic preservatives have been found to be carcinogenic, teratogenic and prone to food poisoning, such as benzoate, which may cause food poisoning, nitrite and nitrate may generate carcinogenic nitrosamines These hazards will not appear in natural preservatives So, what are the natural preservatives in our life? 1 The extract of Forsythia suspensa has inhibitory effect on a variety of gram-positive and negative bacteria, which can effectively prolong the shelf life of food Its antibacterial component is mainly forsythol In Japan, the extract of Forsythia suspensa has been widely used as a natural preservative in food preservation 2 The extract of perilla leaf has broad-spectrum antibacterial effect The main effective components are Perillaldehyde and citral It has obvious inhibitory effect on Staphylococcus aureus, Streptococcus B, diphtheria, Campylobacter, Pseudomonas aeruginosa and Bacillus subtilis Perilla leaf oil also has obvious inhibitory effect on inoculated and naturally polluted mould yeast 3 Garlic extract contains allicin, allicin and Allicin, among which allicin and Allicin are the main antibacterial components The effect of the latter is 50% of that of the former The antibacterial mechanism of allicin may be that the oxygen atom in its molecule combines with the cysteine in bacteria so that it cannot be converted into cystine, thus affecting the important redox reaction in bacteria Allicin has obvious inhibition and bactericidal effect on a variety of cocci and molds 4 Pectin and pectin decomposition products also have antibacterial effect in acid environment, mainly including polygalacturonic acid and galacturonic acid with average polymerization degree of 3-5 Their antibacterial activity is affected by pH, with strong antibacterial activity below pH 6.0 and low antibacterial activity when pH > 6.0 Generally, they are added 0.1% - 0.3% in food They are mainly used in hamburger, noodle soup, cream cake, pickle, etc.