A preservative is a naturally occurring or synthetically produced substance that is added to foods to prevent decomposition by microbial growth or by undesirable chemical changes. Sodium salts of the same acids are very useful as food preservatives. Some examples of such
acids are as follows

(i) Benzoic acid in the form of its sodium salt, constitutes one of the most common food preservatives. Sodium benzoate is a common preservative in acid or acidified foods such as fruit, juices, pickles, etc. Yeasts are inhibited by benzoate to a greater extent than are molds and bacteria.

(ii) Sorbic acid and its salts (sodium, potassium, and calcium) also have preservative activities but the applications of sodium sorbate C6H7NaO2, are limited compared to that for potassium salt.

(iii) Sodium erythorbate C6H7NaO6 is a food additive used predator (Open Grammarly and soft drinks.

(iv) Sodium propanoate Na(C2H5COO)is used in bakery products as a mold inhibitor.