Application of Ionizing Radiation Treatments to Improve Postharvest Quality and Storage Life of Thai Mango ( Mangifera Indica L.)

Fresh Thai mangoes are generally treated with ionizing radiation as a phytosanitary treatment before being exported to overseas markets. The USDA’s Animal and Plant Health Inspection Service accepts Thai irradiated mangoes with an absorbed dose of 0.4 kGy as a suitable postharvest treatment. However, irradiated mangoes can have several quality problems when they reach their destinations, including disease incidence and general spoilage during transportation. The objectives of study were to improve the postharvest quality of fruit being treated with ionizing radiation in combination with hot water treatment for disease control. Two ionizing radiation types, gamma and x-ray, were investigated at a generic dose of 0.4 kGy for the cultivars “Nam Dok Mai Si Thong,” “Nam Dok Mai No.4,” and “Khieo Sawoei.” The mangoes were stored in air at 13 ± 1°C for 12 days, with quality checks every three days. Radiation treatments significantly reduced respiration rate and slowed the rate of increase in the TSS/TA ratio. Consequently, the irradiated mangoes had an effective storage life of 12 days when stored in air. Both non-irradiated and irradiated fruits that received a hot dip water postharvest treatment had a disease incidence of less than 8% at the end of the assessment period. Phytosanitary irradiation of 0.4 kGy, in combination with hot dip water treatment, are reliable treatments for maintaining the quality of Thai mangoes destined for export. Furthermore, x-ray is a promising new quarantine treatment that can be used for Thai mangoes prior to them being exported to international markets.