In Vitro Antimicrobial Activity of Lavender, Mint, and Rosemary Essential Oils and the Effect of Their Vapours on Growth of Penicillium spp. in a Bread Model System

Abstract

The chemical composition, antioxidant activity, and antimicrobial properties of three commercially available essential oils: rosemary (REO), lavender (LEO), and mint (MEO), were determined in the current study. Our data revealed that the major components of REO, MEO, and LEO were 1,8-cineole (40.4%), menthol (40.1%), and linalool acetate (35.0%), respectively. The highest DPPH radical-scavenging activity was identified in MEO (36.85 ± 0.49%) among the investigated EOs. Regarding antimicrobial activities, we found that LEO had the strongest inhibitory efficiencies against the growth of <i>Pseudomonas aeruginosa</i> and <i>Candida</i> (<i>C.</i>) <i>tropicalis</i>, MEO against <i>Salmonella</i> (<i>S.</i>) <i>enterica</i>, and REO against <i>Staphylococcus</i> (<i>S.</i>) <i>aureus</i>. The strongest antifungal activity was displayed by mint EO, which totally inhibited the growth of <i>Penicillium</i> (<i>P.</i>) <i>expansum</i> and <i>P. crustosum</i> in all concentrations; the growth of <i>P. citrinum</i> was completely suppressed only by the lowest MEO concentration. The lowest minimal inhibitory concentrations (MICs) against <i>S. enterica</i>, <i>S. aureus</i>, and <i>C. krusei</i> were assessed for MEO. In situ analysis on the bread model showed that 125 µL/L of REO exhibited the lowest mycelial growth inhibition (MGI) of <i>P. citrinum</i>, and 500 µL/L of MEO caused the highest MGI of <i>P. crustosum</i>. Our results allow us to make conclusion that the analysed EOs have promising potential for use as innovative agents in the storage of bakery products in order to extend their shelf-life.