Sodium benzoate is a type of salt that may occur naturally in some foods but is more likely to be chemically produced and added as a preservative to foods. When used as a preservative, sodium benzoate is typically added to foods in small amounts only. If too much is added, food may take on a very bitter taste.

The reason you will note sodium benzoate listed in the ingredients of so many foods is because it works very well at killing bacteria, yeast and fungi. You will most commonly see it used as a preservative in foods with a high acid content, since sodium benzoate will only work when the pH balance of foods is less than 3.6. It is therefore effective in most sodas, vinegar, fruit juice, and in mixed ingredients like salad dressing. It is additionally used to stop the fermentation process in wines.

Sodium benzoate naturally occurs in several fruits like apples, plums and cranberries. A few sweet spices contain small amounts of sodium benzoate, including cloves and cinnamon. The presence of sodium benzoate in these foods does not necessarily act to preserve them.

You may be able to taste sodium benzoate in foods to which it is added — approximately 75% of people can taste it. People who can taste sodium benzoate can describe it in different ways. Some call it bitter or salty while others think the taste is more on the sweet side. Since many of us drink soft drinks on a regular basis, we are fairly used to tasting this preservative and generally think nothing of it.

There have been some health concerns about the combination of sodium benzoate and ascorbic acid or vitamin C. When the two are mixed, they can form the chemical benzene, which is carcinogenic. However, sodium benzoate on its own is not considered a carcinogen, and you would have to consume a huge amount of it in order to have toxic levels in your body. In mice studies where the animals were fed sodium benzoate, no adverse effects were reported, and the mice’s life expectancies were not shortened, nor was their health affected in any way.

The same cannot be said of benzene, which researchers now show has the ability to affect mitochondria in cells and cause cell death. Scientists have called for the US Food and Drug Administration to retest the potential dangers of sodium benzoate and citric acid in soft drinks, because the tests proving its safety are quite old. In the interim, it may just be a good idea to at least cut down on the amount of soft drinks you consume, and especially to limit soft drink consumption for kids.