Sustainable and Innovative Postharvest Management of Anthracnose Disease in Guavas Through Modulated UV-C Light Treatment

Anthracnose, caused by the Colletotrichum sp. gloeosporioides complex, severely affects guava quality, highlighting the need for sustainable alternatives to synthetic postharvest fungicides. This study is the first to evaluate modulated UV-C radiation as an innovative approach to controlling postharvest diseases and extending guava shelf-life. The modulation frequency significantly influenced mycelial growth and conidial germination, following a quadratic model (R2 = 0.98), with maximum efficacy at ~30 Hz, reducing germination to 5.3 × 104 CFU per plate. In vivo, the combinations of 0.99 kJ m−2/30 Hz and 0.66 kJ m−2/45 Hz inhibited anthracnose incidence and severity. Most physicochemical parameters remained unaffected after seven days of storage. However, treated fruits showed a higher hue angle (h) and lower a*, indicating the maintenance of shades closer to green due to slower chlorophyll degradation, and firmness was preserved, suggesting delayed ripening. Modulated UV-C also significantly reduced the respiration rate, lowering the climacteric peak. These findings demonstrate that anthracnose control depends on the modulation frequency, with 0.99 kJ m−2/30 Hz being particularly effective. Modulated UV-C radiation represents a promising, sustainable, and effective strategy for improving guava postharvest quality and shelf-life.