What Are the Types of Preservatives? A Detailed Guide to Common Types

Preservatives are natural or synthetic chemical ingredients added to food, medicines, pigments, biological specimens and the like to delay spoilage caused by microbial growth or chemical change. Their main role is to inhibit the growth and reproduction of microorganisms, thereby extending the shelf life of food and suppressing spoilage. Let us take a look below at what types of preservatives there are.

Benzoic acid and its salts

Benzoic acid and its salts are white granules or crystalline powder, odorless or with a slight benzoin odor. The optimal pH for preservation is 2.5 to 4.0, and the bactericidal effect is not ideal in products with a pH above 5.0. Because its safety is only 1/40 that of potassium sorbate, Japan has completely banned its use in food.

Sorbic acid and its salts

Sorbic acid and its salts are white crystalline powder, slightly yellow crystalline powder or flakes. They are acidic preservatives with relatively high antibacterial performance that inhibit the growth and reproduction of molds. They mainly work by inhibiting the dehydrogenase system in microorganisms, thereby inhibiting microorganisms and achieving preservation, and they have an inhibitory effect on bacteria, molds and yeasts. Their preservative effect is significantly higher than that of benzoic acid types, at 5 to 10 times that of benzoates. The product has low toxicity, equivalent to half that of table salt. Its preservative effect weakens as pH rises, and the preservative effect is best at pH=3. At a pH of 6 it still has antibacterial ability, but the minimum concentration must not be lower than 0.2%. Its toxicity is even lower than that of parabens. In China it can be used in soy sauce, vinegar, noodles with sauce, beverages, jams and the like.

Dehydroacetic acid and sodium salts

Dehydroacetic acid and its sodium salt are both white or light yellow crystalline powders, stable to light and heat, and degrade into acetic acid in aqueous solution. They are non-toxic to the human body and are a broad-spectrum preservative with a strong inhibitory effect on bacteria, molds and yeasts in food, and are widely used for the preservation and freshness retention of meat, fish, vegetables, fruits, beverages, pastries and the like.

Parabens

Parabens are p-hydroxybenzoates, and the products include methyl, ethyl, propyl and butyl p-hydroxybenzoate and so on. Among them, butyl p-hydroxybenzoate has the best preservative effect. In China, ethyl and propyl p-hydroxybenzoate are mainly used, while in Japan the most widely used is butyl p-hydroxybenzoate. The preservative mechanism of parabens is to destroy the cell membrane of microorganisms, denature the proteins inside the cells, and inhibit the activity of the cell respiratory enzyme system. The antibacterial active component of parabens mainly works in molecular form. Because the hydroxyl group in its molecule has been esterified and no longer ionizes, 60% of the molecules are still present at pH 8, so parabens have good effects across the pH 4 to 8 range.

Sodium diacetate

Sodium diacetate is a preservative commonly used in pickled vegetables. It is safe, non-toxic, and has a very good preservative effect. Its final decomposition products in the human body are water and carbon dioxide. It has a clear inhibitory effect on black root rot fungus, Aspergillus flavus, Listeria and so on. In pickled vegetables, using 0.2% sodium diacetate together with 0.1% potassium sorbate in pickled vegetable products gives a very good freshness-retention effect.

Calcium propionate

Calcium propionate is white crystalline granules or powder, odorless or with a slight propionic acid odor, stable to light and heat, and easily soluble in water. Propionic acid is a product of the oxidation of amino acids and fatty acids in the human body, so calcium propionate is a preservative with very good safety. It has an inhibitory effect on molds, little inhibitory effect on bacteria, and no effect on yeasts, and is commonly used in the fermentation of flour products and the mold prevention of cheese products and so on.

Sodium lactate

Sodium lactate is a colorless or slightly yellow transparent liquid, with no peculiar smell and a slight salty and bitter taste, miscible with water, ethanol and glycerol. The usual concentration is 60 to 80%, and the maximum use limit at a concentration of 60% is 30 grams/kg. Sodium lactate is a new type of preservative and freshness-retention agent, mainly applied in meat and poultry products. It has a strong inhibitory effect on bacteria in meat foods, such as Escherichia coli, Clostridium botulinum, Listeria and so on. By inhibiting foodborne pathogens, it enhances food safety, enhances and improves the flavor of meat, and extends shelf life. It has good dispersibility in raw meat and good adsorption of water, thereby effectively preventing raw meat from dehydrating and achieving freshness retention and moisture retention. It is mainly suitable for roast meat, ham, sausages, chicken and duck poultry products, and braised and marinated products. The reference formula for freshness retention in meat products is 2% sodium lactate and 0.2% sodium dehydroacetate.

Biological food preservatives

The production of biological preservatives in China began with nisin and has a history of ten years, and certain progress has been made in the research, production and application of biological preservatives. Those permitted for use under GB2760 include nisin and natamycin. Polylysine has been developed since 2006, and the work related to applying for polylysine to enter GB2760 is underway, and it is believed that it will be put on the market before long. In addition, there are also products sold on the market that claim to be biological preservatives but are actually compound preparations.