摘要：Aqueous solution of sorbic acid (0.32 mg %) was irradiated with 60Co γ-ray (dose rate 2.48×104 rad/hr) in doses ranging from 0 to to 2.175×104 rad, and decomposition of the acid was examined by spectrophotometry. Absorbance at λ max 255 nm due to sorbic acid decreased with increasing radiation dose and the G (-sorbic acid) value was calculated from the decreasing rate of the absorbance to give 1.85. An aqueous solution of sorbic acid irradiated at the dose 7×105-13×105 rad showed a stronger antibacterial activity than non-irradiated solution against E. coli, in spite of the decrease of sorbic acid in the solution. Therefore, new antibacterial substance was assumed to have been produced in the solution by γ-ray irradiation. This irradiated solution also showed antibacterial activity against 5 other kinds of bacteria. It was also proved that the presence of O2 gas might be essential for the production of the new antibacterial substnce by experiments on antibacterial activity of irradiated solutions sealed with or without O2 gas.
