Biopreservation of dates using citrus peel waste-derived essential oils: a circular economy approach to postharvest mycotoxin control

Abstract

The postharvest contamination of dates by Aspergillus flavus and its aflatoxins is a major food safety concern. Simultaneously, large amounts of citrus peel waste rich in bioactive compounds remain underused. In this study, we valorized citrus peel waste as a source of bioactive essential oils (EOs) to develop a sustainable antifungal strategy. GC–MS profiling revealed distinct volatile compositions in C. limonum, C. sinensis, and C. aurantium EOs, with α-citral, β-citral, γ-terpinene, and β-pinene strongly linked to antifungal potency. in vitro assays showed that C. limonum EO was the most effective, inhibiting mycelial growth by up to 86.7%, suppressing sporulation by 97.7%, and completely eliminating aflatoxin B₁ and B₂ production at 0.5%. Volatile-phase application achieved full inhibition at 1400–1680 µL/L air. In vivo fumigation of inoculated dates reduced fungal counts and aflatoxins by > 79% at 1400 µL/L, and completely eliminated contamination at 1680 µL/L. This work is the first comprehensive study linking agro-industrial waste valorization to controlling aflatoxigenic fungi in date fruits. It highlights citrus-derived essential oils as sustainable, natural alternatives to synthetic fungicides, addressing food safety and waste management challenges.