Citrus spp. are spread mainly in the Mediterranean basin and represent the largest fruit source for human consumption. Postharvest losses, mainly due to diseases and metabolic disorders of fruits, can cause severe wastage, reaching 30 to 50% of the total production. Preserving quality and extending shelf life are essential objectives for postharvest technological innovation, determined by the proper handling, treatment, storage and transport of harvested produce. Moreover, the application of novel sustainable strategies is critical for the reduction of synthetic fungicide residues on fruit surfaces and the impact on the environment caused by waste disposal of fungicides. In this article, the current knowledge about the safest and more sustainable strategies, as well as advanced postharvest handling and storage technologies, will be critically reviewed.

Green and blue molds are the most important postharvest diseases affecting citrus in storage. These diseases are commonly controlled with fungicides, but legislative restrictions, consumer concerns, and the development of resistant strains of the pathogens have increasingly led to the search for alternative methods of control. A pomegranate peel extract (PGE) was very effective in controlling Valencia orange and clementine postharvest rot under commercial conditions. After cold storage and 7 days of shelf life, the incidence of decay on oranges sprayed before harvest with PGE at 12, 6, and 3 g/liter was reduced by 78.9, 76.0, and 64.6%, respectively. Similarly, postharvest dipping treatments with PGE reduced rot by 90.2, 84.3, and 77.6%, respectively. Comparable levels of protection were also achieved on clementines. On both oranges and clementines, the extract provided a significantly higher level of protection compared with imazalil, a fungicide commonly used for postharvest treatments. The high level of efficacy and the consistent results on different fruit species (clementines and oranges) and with different application methods (preharvest and postharvest) were evidence of reliability and flexibility. PGE also showed a strong antimicrobial activity against fungi and bacteria, suggesting its possible use in sanitizers to reduce the microbial contamination of recirculated water in packinghouses. The results of the present study encourage the integration of conventional chemical fungicides and sanitizers with PGE to control citrus postharvest rot.