Inhibition of Listeria monocytogenes and Salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid: the development of synergistic antimicrobial combinations1The work in this manuscript is the subject of a patent application.1

Abstract

This study describes inhibitory properties of combinations of oil of fennel, oil of anise or oil of basil with either benzoic acid or methyl-paraben against Listeria monocytogenes and Salmonella enteriditis. Micro-organisms were cultured at 37°C in broth and viable counts measured over a 48-h period. S. enteriditis was particularly sensitive to inhibition by a combination of oil of anise, fennel or basil with methyl-paraben where there was L. monocytogenes was less sensitive to inhibition by each combination however there was a significant reduction in growth of 4–8 log by combinations of all oils and methyl-paraben at 8, 24 and 48 h. Synergistic inhibition by one or more combinations was evident against each micro-organism.