Sodium Benzoate

What It Is

Sodium benzoate (CAS 532-32-1) is the sodium salt of benzoic acid and a widely used preservative. It appears as a white crystalline powder that dissolves readily in water. It is used to inhibit the growth of bacteria, yeasts, and molds, and is most active in acidic products.

Common Uses

Sodium benzoate is common in acidic foods and beverages such as soft drinks, fruit juices, salad dressings, and condiments, as well as in some cosmetics and cleaning products. It is often chosen for water-based, low-pH formulas where benzoic acid can form. Regulators permit it as a food additive within set concentration limits.

How It Works

In an acidic environment, sodium benzoate converts to benzoic acid, the active antimicrobial form. Undissociated benzoic acid can enter microbial cells, where it lowers internal pH and interferes with energy metabolism, slowing growth. Because this depends on acidity, sodium benzoate is most effective below roughly pH 4.5 and loses activity as pH rises toward neutral. This pH dependence is a key reason it is chosen for some products and not others. A separately studied context is that benzoate and ascorbic acid (vitamin C) together can form small amounts of benzene under certain heat and light conditions, which the FDA has investigated in beverages.

Safety and Regulation

The U.S. FDA classifies benzoic acid and sodium benzoate as generally recognized as safe (GRAS) for use as food preservatives within specified limits. The European Food Safety Authority (EFSA) has re-evaluated benzoic acid and benzoates and set an acceptable daily intake. The FDA has also studied benzene formation in beverages that contain both benzoate and ascorbic acid and has monitored levels in the marketplace. As with any additive, permitted uses and limits are defined in current regulations rather than being open-ended.

Why Natural Flower Power Does Not Use It

We do not use sodium benzoate as a preservative in our products. Because its activity depends heavily on low pH, it is a less flexible fit for our formulas than benzisothiazolinone (BIT), which we have standardized on across our in-house production since 2012. Choosing a single preservative system keeps our formulating and quality checks consistent.

Related Ingredients

Sodium benzoate is often compared with other preservatives such as potassium sorbate and phenoxyethanol, and with NFP's preservative, benzisothiazolinone. For a broader overview of how these compare, see the preservative systems guide.

Sources

• U.S. FDA. "GRAS Substances (SCOGS) Database — Benzoic Acid and Sodium Benzoate." Accessed 2026.
• European Food Safety Authority (EFSA). "Re-evaluation of benzoic acid and benzoates as food additives." Accessed 2026.
• U.S. FDA. "Questions and Answers on the Occurrence of Benzene in Soft Drinks and Other Beverages." Accessed 2026.
• PubChem, National Library of Medicine (NIH). "Sodium Benzoate" record (CAS 532-32-1). Accessed 2026.