Assessment the effect of Gamma radiation on microbial contamination and quality index of three varieties of date Palm fruit (Phoenix dactylifera L.) during storage

Date palm is one of the important fruit in Iran. Maintain of fruit quality, reducing microbial contamination and control of pests are the main objects of date palm during storage. To determine the effect of gamma radiation on date palm, research on 'Piarom' as semi-dry date cultivar and 'Deiri' and 'Zahedi' as dry date cultivars were performed after storage for 4 months at 25±2°C. Fruit harvested and were irradiated by gamma radiation (0, 1, 3 and 5 kG doses). The factorial experiment in a completely randomized design with 3 replications was conducted. Result showed that in all three cultivars, treated fruits had lower water loss and higher flavonoid content. Treated fruits with highest doses of radiation showed better sensory quality and lower pest contamination. Irradiation had significant effect on control of microbial contamination in Deiri and Zahedi cultivars but had no effect on Piarom palm. Zahedi didn’t show any bacterial contamination and other cultivars also showed significant differences. In general, the best dose of irradiation in this study was 5 kG. Results indicated that gamma radiation can be considered for inhibiting microbial contamination and maintain quality of fruits. It can also be used as a technique of future definition.