Effect of Gamma-Irradiation on Disinfection and Storage of Mixed Feed for Chicks

Abstract

The effect of γ-irradiation on disinfection and storage of chick feed in kraft paper bags was investigated to prevent microbiological problems and extend storage life. In various samples obtained in different seasons, the counts of organisms were: total organisms, 2.4×10⁵_??_3.9×10⁶; coliforms, 4.1×10⁴_??_9.0×10⁵; osmophilic moulds, 1.1×10³_??_2.2×10³; and fungi, 1.8×10⁴_??_1.1×10⁵ per gram. By 0.2 Mrad irradiation, the number of total organisms decreased to 1/10_??_1/20; coliforms decreased to 1/20_??_1/50; osmophilic moulds decreased to below identification; and other fungi decreased to 1/10_??_1/1000.
The number of osmophilic moulds in unirradiated samples was increased during storage at high humidity conditions, whereas other microorganisms were not markedly changed. By 0.2 Mrad irradiation, the moulds were eliminated below identification but the number increased rapidly during storage. On the other hand, the occurrence of the moulds during storage was inhibited significantly in the 0.5 Mrad irradiated sample. From these results, it is concluded that mixed feed for chicks can be stored for 3_??_4 months in the summer season after 0.5 Mrad irradiation.