A study on food preservation by irradiation of agricultural and marine products from Cheju island

Salted dry yellow sea bream were vaccum packed in a plastic bags and irradiated at differents levels (0,0.5,1.0,1.5, and 2.0 Mrad) using sup(60)Co source. The irradiated samples were stored at room temperature 5degC. Physical and chemical properties were examined during storage. The total bacterial count was depressed according to level of irradiation applied. It was noted that cold storage after irradiation was more effetive than room temperature. TMA contents slowly increased with higher dosage rates up to 1.5 Mrad but there was a gradual decrease of TMA at the 2.0 Mrad level. It was observed that there was a rapid decrease of TMAO 20 days after irradiation irrespective of storage temperature. The reduction of total nitrogen content was highest in the control but to a lesser degree when irradiation was applied. VBN content increased in all treatments 30 days after irradiation but it was also noted that there was a tendency toward depression of VBN by irradiation. The shelf life of salted dry sea bream was extended by 20 days with irradiation plus room temperature, and by 40 days with irradiation plus cold storage. To extend shelf life of salted dry sea bream, the most effective dosage rate was 1.0 Mrad based on tenderness, bacterial count and rancidity. (Author)