Attività antimicrobica di oli essenziali e dei loro costituenti contro microrganismi patogeni e alterativi di origine alimentare

Major active compounds from essential oils are well known to possess antimicrobial activity against both pathogen and spoilage microorganisms. The aim of this work was (a)to determinate the alteration of the membrane fatty acid profile as an adaptive mechanism of the cells in presence of sublethal concentrations of antimicrobial compounds in response to a stress condition and (b) to evaluate the membrane damage of fatty acids profile caused by the exposition of the cells to high concentrations of the compounds. Methanolic solutions of Thymol, Carvacrol, Limonen, Cinnamaldehyde and Eugenol were added into growing media of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Pseudomonas fluorescens, Brochothrix thermosphacta and Staphylococcus aureus strains. Fatty acid extraction and their gas-chromatographic analysis was performed to assess changing in membrane fatty acid composition. Substantial changes were observed on the long chain unsaturated fatty acids when the E. coli and Salmonella strain's grew in presence of limonene and cinnamaldehyde and carvacrol and eugenol respectively. Brochothrix strain fatty acid profile was influenced by all compounds, while Pseudomonas and S. aureus strains didn't show substantial changes in their fatty acids composition.