Natriumbensoat

Natriumbensoat, known in English as sodium benzoate, is the sodium salt of benzoic acid. Its chemical formula is C7H5NaO2 and its CAS number is 532-32-1. It appears as a white, crystalline powder that is highly soluble in water. In solution it forms the benzoate ion, the form responsible for its preservative action.

It is widely used as a preservative in foods and beverages to inhibit the growth of molds, yeasts, and some bacteria. It is also used in cosmetics and medicines to prevent microbial contamination. In foods, sodium benzoate is commonly employed at concentrations up to about 0.1% by weight, though exact limits vary by country and product. Its antimicrobial effect is stronger in acidic environments, where benzoic acid (the uncharged form) can penetrate microbial cells and disrupt metabolism.

Regulatory status varies by jurisdiction. In the United States, the FDA approves sodium benzoate as a food preservative (GRAS). In the European Union it is permitted as a food additive (E211) within product-specific limits. The allowed levels depend on the type of product and local regulations. The additive is monitored to ensure it does not contribute to unsafe levels of benzene under certain conditions.

Safety and health considerations: Sodium benzoate is of low acute toxicity. It can cause irritation at high exposures and may cause adverse reactions in sensitive individuals. Some studies have explored potential behavioral effects when combined with certain artificial colorings, but evidence remains inconclusive. A concern in beverages is the possible formation of benzene under certain conditions, leading manufacturers to reformulate to minimize this risk.

Environmental aspects: Sodium benzoate is biodegradable under aerobic conditions and is not considered highly persistent in the environment. It is metabolized by microorganisms to hippuric acid and eventually to carbon dioxide and water.