EFFECT OF GASEOUS OZONE EXPOSURE ON THE CONTROL OF COLLETOTRICHUM GLOEOSPORIOIDES OF PAPAYA DURING AMBIENT STORAGE

The effect of gaseous ozone to control postharvest decay of papaya, particularly anthracnose caused by fungus Colletotrichum gloeosporioides was investigated. Different concentrations of ozone (0 (control), 1.5, 2.5, 3.5 and 5 ppm) were applied for 96 h at room temperature (25±3°C) in a completely randomized design setup with four replications. Radial mycelial growth and conidial germination were evaluated in vitro after fungal exposition to different doses. The effects of ozone on disease incidence and severity of papaya inoculated with C. gloeosporioides during ambient storage (25±3°C, 60% relative humidity) for 14 days were also determined. Significant (p<0.05) inhibition in radial mycelial growth of C. gloeosporioides was observed in all treatments of ozone compared to the control during eight days of incubation at room temperature (25±3°C). However, the maximum inhibition in radial mycelial growth and conidial germination was observed in petri plates exposed to 5 ppm of ozone for 96 h (41.20%) and (100%), respectively. Microscopic analysis showed that ozone exposure to 5 ppm caused disintegration of spore. Exposure of fruits to ozone also leads to significant suppression of disease incidence and severity in papaya. Therefore, these results supported that application of gaseous ozone as a safe non-thermal food preservation technique for papaya, which can be used successfully as an alternative to chlorination.