Assessment of antifungal treatments in the post-harvest of oranges (Citrus sinensis)

The aim of this study was to evaluate the effectiveness of mineral oil, sodium bicarbonate, sodium hypochlorite, distilled water, and the fungus Trichoderma harzianum as alternatives for fungal control in oranges during postharvest. One hundred and twenty oranges were used, distributed in groups of five fruits per treatment. Each orange was subjected to one of the following treatments: T. harzianum (1 × 109 spores/mL), sodium bicarbonate (1%), sodium hypochlorite (1%), mineral oil, or distilled water, immersed for two minutes. Twenty additional oranges received no treatment and served as a control. The oranges were stored for 14 days at room temperature in plastic containers sealed with absorbent paper. The study was conducted in quadruplicate to determine fungal growth or other alterations. Growth of the fungus Penicillium digitatum was observed, being more frequent in oranges treated with distilled water, with 30% growth. In the treatments with sodium hypochlorite, T. harzianum, and sodium bicarbonate, growth reached only 20%. The control oranges showed 30% growth, like the distilled water treatment. Meanwhile, in oranges treated with mineral oil, fungal growth occurred in only 5% of the fruit, showing differences between treatments and demonstrating the greatest efficacy in postharvest fungal control. These results suggest that mineral oil is the most effective alternative for fungal control in oranges during postharvest. P. digitatum was identified by observing its colonial and microscopic morphology.