(176j) Enhanced Food Safety: Extending Antimicrobial Efficacy of Commercial Wax through Incorporation of Nano-Encapsulated Essential Oil

Approximately 50% of agricultural produce is lost during post-harvest handling, storage, and transportation, resulting in huge financial losses. In addition, contaminated fruits and vegetables can act as vectors for transmitting foodborne illnesses via cross contamination and unhygienic handling practices. Consequently, there is a pressing need to develop innovative technologies aimed at enhancing agricultural productivity, extending shelf life, and mitigating the risk of foodborne illnesses, while also addressing the persistent challenge of ensuring the quality of exported food commodities to distant countries. These concerns become even more critical during the handling of ready-to-eat and unprocessed fresh produce.

To tackle these challenges, we have implemented a hybrid wax coating methodology, which involves infusion of nano-encapsulated cinnamon essential oil (EO-NE) into food-grade wax commonly associated with produce coatings. To validate our concept, we selected apples as the model substrates. We conducted comprehensive investigations encompassing physical, chemical, and surface characterization: scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), contact angle analysis, UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Additionally, we have investigated the kinetics of essential oil release through our hybrid wax coatings, to quantify its delayed release and sustained antimicrobial activity profile. Furthermore, we have undertaken comprehensive antimicrobial studies to evaluate the efficacy of our hybrid wax coatings against Escherichia coli O157:H7, Staphylococcus aureus, and Aspergillus, the foodborne pathogens commonly encountered in the post-harvest processing.

The applied coatings demonstrated a static contact angle of 85 ± 1.6°, with advancing and receding contact angles of 90 ± 1.1° and 53.0 ± 1.6°, respectively, closely resembling the wetting properties of natural waxes on apples. Nanoencapsulation significantly prolonged the release of essential oil, extending the half-life by 61 hours compared to the bulk-dispersed essential oil wax coatings. This release correlated with statistically significant reductions (p = 0.05) in bacterial populations, providing both immediate and delayed (after 72 hours) antibacterial effects. In addition, the disc diffusion experiment on hybrid wax substrates showed great aversion toward A. flavus with the initial zone of inhibition measuring 13.5 ± 0.15 mm and no hyphae and conidiophores growth on the substrates (with coatings) even after 10 days of incubation.

Therefore, the utilization of this advanced produce wax coating technology offers significant potential for enhancing food safety and providing enhanced protection against bacteria and fungi for produce commodities.