Evaluation of phototoxic properties of some food additives: sulfites exhibit prominent phototoxicity.

Additives are used widely to enhance the quality of food products. To identify possible phototoxic properties, 13 food additives (benzoic acid, sodium benzoate, 4-hydroxybenzoic acid, 4-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic ethyl ester, 4-hydroxybenzoic acid propyl ester, p-hydroxybenzoic acid n-butyl ester, benzyl alcohol, sorbic acid, potassium sorbate, propionic acid, sodium disulfite and sodium sulfite) were evaluated in vitro by means of a photohemolysis test using suspensions of human erythrocytes. Irradiation was performed with various light sources differing with regard to their spectral irradiance. Sodium sulfite and sodium disulfite induced photohemolysis up to almost 100%, the effect depending on the concentration of the compounds and UV dose administered. Radiation rich in UVB was most effective; a sunlight-simulating lamp induced photohemolysis to a lesser degree. All other substances tested did not cause significant photohemolysis. As sulfites are frequently encountered, they may contribute to UVB sensitivity. The clinical significance of these findings has to be established by further work.