Effect of lemon, thyme and oregano essential oils on organoleptic quality and histamine production in sardine fillets stored at 10°C

The use of essential oils is considered an emerging approach to preserving food quality due to the antibacterial phenolic compounds they contain. The antibacterial power, histamine content and the influence of incorporating lemon, thyme and oregano essential oils on the organoleptic quality of sardine fillets, stored at 10°C was evaluated. The essential oils studied showed significant antibacterial activity against Klebsiella ozaena, Enterobacter cloacae, Morganella morganii, Proteus mirabilis, Citrobacter freundii and Providencia rustigiani. Lemon EO had the lowest inhibition diameter, while thyme EO showed the highest. Application of these oils at a concentration of 5% to sardine fillets revealed a beneficial effect on sensory attributes, improving odor and taste and preserving the organoleptic quality of the sardine up to the sixth day of storage at 10°C without reaching the organoleptic rejection threshold. The essential oils studied controlled bacterial multiplication: thyme EO revealed a significant reduction in bacterial microflora of around 57%, demonstrating bactericidal activity, while the application of oregano EO favored bacteriostatic action, while lemon EO retarded bacterial proliferation. In addition, no histamine production occurred following the incorporation of these EO into sardine fillets throughout the storage period. Lemon, thyme and oregano essential oils have significant antibacterial activity and may offer a complementary solution for histamine control in fish products.