Low-dose gamma irradiation following hot water immersion of papaya (Carica papaya linn.) fruits provides additional control of postharvest fungal infection to extend shelf life

• Storage of papaya extended to 28 days whilst retaining commercial quality.
• Additive effect of low gamma irradiation (0.08 kGy over 10 min) and hot-water treatment.
• Significant reduction in surface fungal lesions.
• No significant impact on colour change or flesh quality during storage.

Low-dose gamma irradiation (0.08 kGy over 10 min), a level significantly below that required to satisfy the majority of international quarantine regulations, has been employed to provide a significant reduction in visible fungal infection on papaya fruit surfaces. This is appropriate for local and national markets in producer countries where levels of commercial acceptability can be retained despite surface lesions due to fungal infection. Irradiation alone and in combination with hot-water immersion (50 °C for 10 min) has been applied to papaya (Carica papaya L.) fruits at both the mature green and 1/3 yellow stages of maturity. The incidence and severity of surface fungal infections, including anthracnose, were significantly reduced by the combined treatment compared to irradiation or hot water treatment alone, extending storage at 11 °C by 13 days and retaining commercial acceptability. The combined treatment had no significant, negative impact on ripening, with quality characteristics such as surface and internal colour change, firmness, soluble solids, acidity and vitamin C maintained at acceptable levels.