Pre-Storage Fruit Injury Accelerates Apple Deterioration During Cold Storage and Shelf Life: Importance of Sorting and Mitigation by Sustainable Postharvest Treatments

Pre-storage fruit injuries are a major yet often underestimated cause of postharvest losses in apples, particularly during prolonged cold storage. This study evaluated the impact of minor pre-storage injuries on fruit deterioration and assessed the effectiveness of ammonium bicarbonate (2%) and clove bud essential oil (0.2%) as eco-friendly postharvest treatments compared with the fungicide fludioxonil (Scholar). Fresh red and yellow apples were classified as either intact fruit or fruit bearing minor injuries affecting less than 2% of the surface area (approximately 2 mm lesions). Treatments were applied by spraying before storage at 5 °C for six months, followed by 10 days of shelf life at 20 °C. Minor injuries significantly increased postharvest decay, weight loss, and quality deterioration in both cultivars. Injured yellow apples exhibited decay incidence of 17–24% and disease severity of 10.5–17.8%, whereas the more susceptible red apples showed decay incidence of 44.6–60% and disease severity of up to 50%. In contrast, non-injured fruit maintained better physicochemical quality and generally exhibited less than 5% decay incidence. Responses to storage and treatments differed between cultivars. Ammonium bicarbonate effectively reduced decay and helped maintain firmness in yellow apples, providing protection comparable to that of fludioxonil, whereas Scholar was the most effective treatment for reducing decay in red apples. Clove essential oil reduced disease development in non-injured fruit but showed limited effects on firmness preservation. The residual activity of fludioxonil remained detectable after prolonged storage, as demonstrated by inoculation assays performed after storage. The results demonstrate that fruit integrity at harvest is a critical determinant of successful long-term storage and that the benefits of postharvest treatments are substantially reduced when fruit are mechanically injured. Preventive treatment of uninjured fruit with ammonium bicarbonate or Scholar can significantly reduce postharvest losses, while careful handling and sorting to eliminate injured fruit remain essential components of sustainable apple storage management.