Benzoic acid and its sodium salt, sodium benzoate, are widely used food preservatives. Benzoic acid is a monocarboxylic acid, naturally found in many plants and animals. Sodium benzoate is synthesized by neutralizing benzoic acid with sodium hydroxide. Both compounds inhibit the growth of bacteria, yeast, and molds in food products, therefore extending shelf life.

Benzoic acid is produced through the oxidation of toluene, a process that typically involves using air and a catalyst, such as cobalt or manganese naphthenate. The reaction results in benzoic acid, which is then purified through distillation and recrystallization. Sodium benzoate is produced by reacting benzoic acid with a sodium hydroxide solution; the resulting solution is evaporated to yield sodium benzoate as a white, crystalline powder.

Benzoic acid and sodium benzoate exhibit antimicrobial properties by interfering with the microorganisms' enzymatic activities and cell membrane integrity. They are most effective under acidic conditions (pH 2.5 to 4.0) where the undissociated benzoic acid can penetrate the cell membrane. This inhibits the growth and survival of spoilage microorganisms.

Benzoic acid and its sodium salt find application in a variety of food and beverage products, including: carbonated beverages, fruit juices, pickles, salad dressings, jams, and jellies. They are also employed in some pharmaceuticals and cosmetics to prevent microbial growth. The compounds are generally recognized as safe (GRAS) by regulatory agencies, when used within permitted concentrations.

Benzoic acid and sodium benzoate are typically packaged in multi-layer kraft paper bags or fiber drums, with inner polyethylene liners, to protect against moisture and contamination. They should be stored in a cool, dry, and well-ventilated area, away from direct sunlight and incompatible substances, to maintain their stability and prevent degradation.

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