Investigation of the effectiveness of some plant compounds and essential oils of corymbia citriodora against foodborne pathogens

Abstract

The purpose of this study was to determine the antibacterial activity of plant derived compounds and essential oils of Corymbia citriodoraagainst selected Gram negative and Gram positive foodborne pathogens in broth dilution assay. The combination of compounds (cineole, terpinen-4-ol and ?-terpineol; CT?T) were further tested at three different concentrations (0.2, 0.4 and 0.8%) for the killing effect against E. coliO157:H7 and L. monocytogenesin milk including whole fat and skim fat. CT?T showed antimicrobial activity against all bacteria tested at minimum inhibition concentrations (MICs) from 0.125% to 1% in broth dilution assay. Linalool was also found to be antimicrobial at MICs between 0.25% and 2%, but not for Enterococcus casseliflavus. Further study carried out in milk showed that CT?T at concentrations of 0.4% and 0.8% significantly reduced the population of E. coliO157:H7 under detection limit in skim milk, whereas it was only effective at 0.8% in whole fat milk. CT?T, on the other hand, shown to be less active towardsL. monocytogenesas only significant effect was observed at 0.8% in skim milk. Taken together results of the present study indicate that plant derived compounds could be valuable alternatives to inactivatefoodborne pathogens in milk.

The purpose of this study was to determine the antibacterial activity of plant derived compounds and essential oils of Corymbia citriodoraagainst selected Gram negative and Gram positive foodborne pathogens in broth dilution assay. The combination of compounds (cineole, terpinen-4-ol and ?-terpineol; CT?T) were further tested at three different concentrations (0.2, 0.4 and 0.8%) for the killing effect against E. coliO157:H7 and L. monocytogenesin milk including whole fat and skim fat. CT?T showed antimicrobial activity against all bacteria tested at minimum inhibition concentrations (MICs) from 0.125% to 1% in broth dilution assay. Linalool was also found to be antimicrobial at MICs between 0.25% and 2%, but not for Enterococcus casseliflavus. Further study carried out in milk showed that CT?T at concentrations of 0.4% and 0.8% significantly reduced the population of E. coliO157:H7 under detection limit in skim milk, whereas it was only effective at 0.8% in whole fat milk. CT?T, on the other hand, shown to be less active towardsL. monocytogenesas only significant effect was observed at 0.8% in skim milk. Taken together results of the present study indicate that plant derived compounds could be valuable alternatives to inactivatefoodborne pathogens in milk.