Impact of Storage Temperature on the Stability of Preservatives
Sodium Benzoate is a chemical preservative widely used in the food industry, but has become highly controversial over the past few decades due to the fact that it reacts with ascorbic acid to produce benzene, a carcinogenic contaminant. Although past studies have looked at benzene levels in foods, their studies have always been limited by the possibility of benzene contamination from an external source, and not the preservative itself.
Aim: To determine the effect of storage temperatures (4, 10, 33, 37 and 50 °C) on Sodium Benzoate concentration in orange juice, and the theoretical yield of Benzene.
Method: A titration method was employed by converting the preservative into benzoic acid and titrating with 0.005 mol/dm3 NaOH.
Results: Results showed a nonlinear decrease in Sodium Benzoate concentration (max concentration. 0.177%, min. 0.0145%), along with an exponential increase in Benzene production (max. 0.07152% increase).
Conclusion: The results of this experiment support the hypothesis that Benzene is formed from Sodium Benzoate, and that the amount of Benzene formed depends upon the temperature at which the food is stored. This has major implications on the importance of monitoring storage temperature for Sodium Benzoate-preserved beverages.