Effects of clove (Syzygium aromaticum) and rosemary (Salvia rosmarinus) essential oils and their nanoemulsion (pectin/chitosan) on Aspergillus flavus survival and the inhibition of total aflatoxin in beef burger patties

This study evaluated the antifungal and antiaflatoxigenic effects of clove (Syzygium aromaticum) and rosemary (Salvia rosmarinus) essential oils (EOs) and their nanoemulsions (pectin/chitosan) in a beef burger model contaminated with Aspergillus flavus. EO-loaded nanoparticles (CLEO-NPs and REO-NPs) were prepared using ionic gelation and characterised via transmission electron microscopy. The antifungal activity and minimal inhibitory concentrations (MICs) were determined by macrodilution and agar well diffusion. CLEO-NPs and REO-NPs showed lower MICs (1.56 and 0.39 μl/ml, respectively) than their pure oil forms. Burger patties artificially inoculated with A. flavus or aflatoxin were treated with EOs and their nanoforms and stored under refrigeration. CLEO and REO treatments reduced A. flavus counts by 3.7 and 2.4 log CFU/g, respectively, while the nanoformulations eliminated fungal growth by day 9. Aflatoxin levels were reduced by 23.2% with CLEO and 24.7% with REO, whereas CLEO-NPs and REO-NPs achieved reductions of 49.7% and 54.7%, respectively. Sensory attributes remained acceptable across all the treatments, with the NP groups scoring highest. These results demonstrate the superior efficacy of EO nanoemulsions for fungal control and aflatoxin reduction in meat products, supporting their potential use as natural food preservatives.