Extending the shelf-life of fresh-cut fruit salad combining conventional packaging in polylactic acid double bottom container with dynamic antimicrobial imines of trans-2-hexenal and chitosan

Trans-2-Hexenal (HX) was stabilized in amino-polysaccharide chitosan films via reversible imine formation and were integrated into the aliphatic polyester polylactic acid (PLA) container featuring a perforated double bottom for the preservation of a minimally processed mixed fruit salad. Fruit exudate triggered imine hydrolysis, enabling controlled release of HX. After 12 days of storage at 6 °C, control samples reached microbial loads of 5.2 log CFU/g for moulds, yeasts and mesophilic bacteria, whereas active packages showed significantly lower count. Moreover, active system significantly reduced inoculated populations of Salmonella enterica, Listeria innocua and Escherichia coli, while effectively preserving quality attributes such as colour in pineapple and melon. By day 12, HX sorbed in the salad reached 3.1 ± 0.4 and 2.0 ± 0.4 μg/g when using 0.5 and 0.25 g of active film, respectively. Toxicological assessment using Caenorhabditis elegans showed 100% survival, confirming the safety of HX levels found in the salad.