Antimicrobial activity of thyme essential oil nanoemulsions on spoilage bacteria of fish and food-borne pathogens. (August 2020) - Ozogul, Yesim
Abstract: The antibacterial activities of nanoemulsions based on essential oil of thyme and its purified version on food-borne pathogens ( S. Paratyphi A, S. aureus, K. pneumoniae, and E. faecalis ) and spoilage bacteria of fish ( P. luteola, P. damselae, V. vulnificus, E. faecalis, S. liquefaciens, and P. mirabilis) were evaluated using disc diffusion, MIC and MBC. The flavour compounds of extracted thyme oil were determined using GC-MS. Physical properties of nanomulsions (viscosity, thermodynamic stability, droplet size, and refractive index) were analysed. A scanning electron microscope (SEM) was used to observe morphology changes in the cell wall of selected bacteria. The results showed that non-purified thyme-based nanoemulsions were more effective on food-borne pathogens. Damage in bacterial cell membranes after nanoemulsion treatments were observed. Conversion of thyme oil into a nanoemulsion increased antibacterial activity and its nano-form can be used as an alternative antimicrobial agent in processed or packaged fish or food products. Highlights: Nanoemulsion based on thyme essential oil were produced and its physicochemical properties were determined. The antimicrobial activities of nanoemulsion on food-borne pathogens and fish spoilage bacteria were compared. Thyme essential oil based nanoemulsion improved antibacterial activity. SEM showed that nanoemulsion treatment caused bacterial cell membrane damage.