Impact of GRAS compounds applied by ultrasonic nebulization on decay control and quality parameters in Persian lime

The application of generally recognized as safe (GRAS) substances for postharvest fungal control of fruit is an alternative to the conventional use of synthetic fungicides. In this study, two GRAS compounds were applied by ultrasonic nebulization (USN) to lime fruit for the control of Penicillium italicum, the cause of blue mold. Lime fruits were treated with sodium bicarbonate (1, 2, 3% w/v), acetic acid (0.5, 1, 1.5% w/v) and sterile distilled water by USN for 5, 10-15 min. The effect of the USN treatments was evaluated in vitro, selecting the agent with the best effect. In vivo, the incidence and severity of blue mold disease and lime fruit quality parameters were evaluated. Although sodium bicarbonate inhibited P. italicum in vitro tests, USN treatments with acetic acid significantly inhibited 75.4% of mycelial growth and 100% of P. italicum germination. USN treatments (1% and 1.5% acetic acid) reduced disease incidence and severity (preventive and curative tests) on fruit stored at 25 °C; however, at 15 °C there was no significant difference with respect to USN of sterile distilled water. Lime quality parameters were not adversely affected by USN treatments with acetic acid. The application of 1 or 1.5% acetic acid by USN appears to be a promising option for the control of blue mold disease in Persian lime fruits.