Resistance of Aflatoxin to Chemical and Biological Changes by Gamma Irradiation

The preliminary studies on the resistance of Aflatoxin against chemical and biological changes by gamma irradiation (7, 15, or 30 Mrad) were carried out by means of thin-layer chromatography, ultraviolet absorption spectrophotometry, fluorescence spectrophotometry and yolk sac inoculation with 5-day eggs. No marked changes were observed in the u.v. and fluorescence spectrum between treated and untreated Aflatoxin even on irradiation with 30 Mrad. However, a blue fluorescence spot with a smaller Rf value than Aflatoxin G1 was clearly found after the treatment with 30 Mrad, but never in untreated samples. The spot of Aflatoxin G1 on the TLC plate disappeared and the blue spot mentioned above was also found after the irradiation when Aflatoxin was diluted in the buffer solutions. Aflatoxin was biologically quite resistant to irradiation. Aflatoxin was, however, decomposed in some inorganic salt solutions and this tendency was accelerated by the irradiation treatment. (author)