Sodium bicarbonate for the postharvest control of Colletotrichum sp. and quality maintenance in papaya (Carica papaya L.)

Anthracnose, caused by Colletotrichum sp ., is a primary cause of postharvest losses in papaya ( Carica papaya L .). This study evaluated the application of sodium bicarbonate (SB) as a safe, low-residue alternative to synthetic fungicides for disease control and quality maintenance. Papayas artificially inoculated with Colletotrichum sp . were treated by immersion with SB solutions at 1%, 2%, and 3% (w/v), a commercial fungicide (prochloraz), and an untreated control ( n = 10 per treatment). Fruits were stored for 28 days at 13 ± 1 °C, followed by 7 days at 20 ± 2 °C to simulate shelf-life conditions. Disease severity, physicochemical attributes (weight loss, firmness, color, total soluble solids, pH, titratable acidity), and sensory quality were evaluated at days 0, 14, 21, 28, and 35. Results showed that the 2% SB treatment was the most effective, significantly reducing lesion diameter to 1.81 ± 0.11 cm by day 35, compared to 4.14 ± 0.31 cm in the control. The 2% SB application also minimized weight loss, preserved pulp firmness, and maintained sensory acceptability without negatively altering maturation parameters. These findings suggest that a 2% SB immersion represents a viable, sustainable postharvest treatment for papaya anthracnose management, with potential for integration into commercial handling protocols.