Oregano and Thyme Essential Oils Encapsulated in Chitosan Nanoparticles as Effective Antimicrobial Agents against Foodborne Pathogens

The use of natural compounds with biocidal activity to fight the growth of bacteria responsible for foodborne illness is one of the main research challenges in the food sector. This studyreports the preparation and physicochemical characterization of chitosan nanoparticles loaded withThymus capitatus (Th-CNPs) and Origanum vulgare (Or-CNPs) essential oils. The nanosystems wereobtained by ionotropic gelation technique with high encapsulation efficiency (80-83%) and loadingcapacity (26-27%). Nanoparticles showed a spherical shape, bimodal particle size distribution, andgood stability (zeta potential values > 40 mV). The treatment of the nanosuspensions at different temperatures (4 and 40 oC) and storage times (7, 15, 21, and 30 days) did not affect their physicochemicalparameters and highlights their reservoir ability for essential oils also under stressful conditions. BothOr-CNPs and Th-CNPs exhibited an enhanced bactericidal activity against foodborne pathogens(S. aureus, E. coli, L. monocytogenes) than pure essential oils. These ecofriendly nanosystems couldrepresent a valid alternative to synthetic preservatives and be of interest for health and food safety.