This study was conducted on "Washington navel" oranges to reduce mold spoilage and maintain regular quality characteristics during shelf life at ambient conditions by CaCl2 (1%), chitosan (1%) and Rhodotorula mucilaginosa (yeast, 108 CFU/ml), treatments as biological eco-friendly agents. All applied treatments reduced both disease incidence (averaging 6.68-14.70%) and severity (averaging 4.40-9.00%) compared to the control (14.70 and 11%, for disease incidence and severity, respectively). The most effective treatments were R. mucilaginosa in combination with either CaCl2 or chitosan, followed by R. mucilaginosa alone. Among the applied treatments, R. mucilaginosa in combination with chitosan was the most effective treatment followed by R. mucilaginosa in combination with CaCl2 to reduce weight loss, maintain higher firmness, vitamin C, titratable acidity (TA%) and total soluble solids (TSS%). Additionally, fruit peel color, evaluated by lightness and Hue angle (h degrees), was not significantly affected by the applied treatments, indicating no negative impact of such treatments on peel color. In conclusion, R. mucilaginosa in combination with chitosan or CaCl2 treatments can be used as a biological agent to effectively control blue and green rot and maintain regular fruit quality. However, using chitosan, CaCl2, or yeast alone did not achieve the desired effect.
