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Sodium Benzoate Good or Bad?

After receiving some emails from concerned customers with confusion on the subject of this natural occurring ingredient called Sodium Benzoate, we decided to clear up some confusion by elaborating further on this subject.

Sodium Benzoate is a natural occurring sodium salt in cranberries and apples. When Sodium Benzoate is created in a lab it comes in a white crystalline light odorless form. The ingredient works against bacteria and fungus (antimicrobial agent), the reason for its popularity in the industry of preserving. Sodium Benzoate can be found in a number of food products such as marmalades, soft drinks, vinegars, soy sauces and so further. It works so well and is considered safe that its presence is also in many skin care products.

Lately, Sodium Benzoate has been receiving spotlight.  It's said that Sodium Benzoate causes cancer but this is in fact a false accusation. Sodium Benzoate is safe and used in organic cosmetics. If Sodium Benzoate was not safe you would have to stop consuming your fruits such as apples, prunes, and cranberries. Even cinnamon and cloves contain sodium benzoate.

What has been mistaken is that when both ingredients; Sodium Benzoate and Ascorbic Acid are present with each other in the same concoction like sodas or fruit drinks with "heated" conditions that a metal catalyzed hydroxyl radical reaction occurs and forms a chemical called Benzene. Benzene, is in fact a known carcinogen. Metals including copper, and iron can all influence the levels of benzene to grow. This is why sodas and fruit drinks in such packaging have been under scrutiny because they give the right condition for benzene to form. 

In further investigations, such as Gardner and Lawrence (1993), demonstrated that benzene from Benzoic acid in the presence of ascorbic acid, and metal such as copper and Iron can be formed. The chemical reaction of the transition metal ions in low concentrations are also found in drinking water, catalyzed.

At higher ascorbate concentrations, the concentration of benzene was negatively correlated with the concentration of the added ascorbate. The pH dependence of the reaction was measured by a pH of 2-7. At pH 2, the benzene formation was maximal (about 37 nmol / L) at higher pH was significantly less benzene formed. In addition, a relationship between the amount of the formed benzene and the concentrations of added copper sulfate (0.05-4 mmil / L) and ferric sulfate (0.05, 1 mmol / L) was examined. At 1 mmil / L copper sulfate or)) 5 mmol / L ferrous sulfate, the maximum amount of benzene was formed in each case. Meaning, the reaction to form benzene taking place in such "heated" environments is influenced also by the pH of the liquid substance. Which we can come to a summary that sugary soft drinks and fruit juices prove to influence the chemical benzene to form due to its pH averaging at 3.

The forming of Benzene is influenced by a number of factors and they include:

  • Formulations containing ascorbic acid and sodium benzoate show increased benzene when exposed to heat or light.
    Other chemicals, such as erythorbic acid (an isomer of ascorbic acid), EDTA, oxygen, and sweeteners (e.g., high fructose corn syrup), influence benzene formation.

  • Sweeteners may inhibit the reaction since the problem is most noticeable in diet drinks. EDTA appears to inhibit the reaction.
    Like ascorbic acid, erythorbic acid may lead to benzene formation.
    Removal of oxygen through CO2 or N2 sparge may inhibit benzene formation.

  • At low concentrations of ascorbic acid, increasing levels of ascorbic acid result in increased benzene production. At higher levels of ascorbic acid (i.e., above the level of benzoic acid in the product), however, benzene production decreases (likely through competitive action of the ascorbic acid as a hydroxyl radical scavenger in the reaction).

  • Metals (e.g., iron and copper) likely present in the water used to prepare the products serve as catalysts in the production of benzene.

  • In experimental mixtures, the maximum amount of benzene was produced at pH 2.

  • Production dropped sharply as the pH increased from pH 3 to pH 5, and no benzene was detected at pH 7.

  • Citric acid in place of ascorbic acid also forms benzene, although not as readily.

  • Solutions of ascorbic acid with benzoic acid anhydride, acetophenone, and benzaldehyde also form benzene after 24-hour exposure to light.


We use Ecocert Sodium Benzoate as an ingredient in some of our products. Ecocert Sodium Benzoate is certified by a European Organization that conducts inspections in over 80 countries. You can find more information about Ecocert by doing a search on the internet. 

Until we find a natural alternative preserving agent, we will continue to use Sodium Benzoate due to its stability, safety record, and long history of preserving. 

Sources and References:

Bundesinstitut für Risikobewertung
American Institute of Baking

Draft EU Risk Assessment Report on Benzene (Environment Part, May 2002, Human Health Part March 2003)

Fleming-Jones ME, Smith RE (2003) Volatile organic compounds in foods: A five year study. Journal of Agricultural and Food Chemistry 51: 8120-8127.

Gardner LK, Lawrence GD (1993) Benzene production from decarboxylation of benzoic acid in the presence of ascorbic acid and a transition-metal catalyst.
Journal of Agricultural and Food Chemistry 41 (5): 693-695.

McNeal TP, Nyman PJ, Diachenko GW, Hollifield HC (1993) Survey of benzene in foods by using headspace concentration techniques and capillary gas chromatography.
Journal of AOAC International 76 (6): 1213-1219.

Page BD, Conacher HBS, Weber D, Lacroix G (1992) A survey of benzene in fruits and re- tail fruit juices, fruit drinks, and soft drinks.
Journal of AOAC International 75 (2): 334-340.

Ramsay S (1994) Benzene standard for UK. The Lancet 343: 412.