Postharvest Application of Black Mustard (Brassica nigra) Seed Derivatives in Sweet Cherry Packaging for Rot Control

Packaging is essential for protecting, distributing, and trading fresh fruit. Antimicrobial packaging, which incorporates natural or synthetic bioactive compounds, can inhibit microbial growth, extend shelf life, and reduce reliance on synthetic fungicides. This study aimed to evaluate the effect of allyl isothiocyanate (AITC), released from black mustard seeds, on the quality and fungal development of 'Burlat' sweet cherries during postharvest storage under modified atmosphere. The in vitro and in vivo antimicrobial activity of AITC, released from different amounts of mustard seeds in an 'Inbox' system, was compared with fludioxonil, a synthetic fungicide authorised for postharvest use on stone fruits in the European Union. The impact of these treatments on weight loss, headspace gas composition, fruit decay, physicochemical and microbiological quality was also analysed. Results showed that AITC inhibited the in vitro growth of Cladosporium cladosporioides, Monilinia laxa and Penicilium expansum, and significantly reduced Alternaria alternata, Botrytis cinerea, and Geotrichum candidum after 96 h at 25 °C and 99% RH. Treatment with 100 mg of mustard seeds achieved rot control comparable to fludioxonil, while maintaining higher firmness and delaying skin darkening after 28 days. Overall, natural AITC from mustard seeds appears to be a promising alternative for preserving sweet cherry quality.