Re: How toxic is sodium benzoate?

Sodium benzoate is a very widespread food preservative used much under 0.1%
in many foods from soup to cereals.  The considerable time between the
production and the consumption of food today makes some use of
preservatives necessary in order to prevent spoilage and undersirable
alterations in color, flavor, or nutrients.  Degradation pathways for
benzoic acid (produced in the body from the sodium salt) have been studied
in detail and have shown the harmlessness of this substance: 75-80% is
excreted within 6 hours, and the total dose leaves the body within about 10
hours.  It does not cause cancer.  The limit of sodium benzoate in foods is
not because of its toxicity, but at levels higher than 0.1% will leave an
unacceptable aftertaste.  Foods containing this preservative are much
healthier than non-preservative foods since harmfull microorganism growth
is inhibited, food oxidation is prevented, and food nutrients are preserved.   

 Chronic toxicities were examined in rats fed diets containing up to
a total of 1%. After 4 generations there were no changes in normal
patterns of growth, reproduction, lactation and no morphological
abnomalities of organs.  Acute toxicity studies, where one large dose of
sodium benzoate is given to animals, showed no lethal effects until 2
grams per kg. body wt. was administered. One could not eat enough foods
containing sodium benzoate to even get 0.002% of this amount!

        Limits of sodium benzoate in foods is not because of toxicity, but
it will impart a taste that will make some  foods unacceptable. This is a
very non-toxic compound and foods containing presevatives are usually much
healthier since harmful microorganism growth is inhibited, oxidation is
checked, and nutrients, natural or added, are saved.                  

Moderator's note:  You can find out more about the hazards associated with 
different compounds on their Material Safety Data Sheet.  Online versions are 
available in the chemistry section of our MadSci Library for more information on Chemistry.