Antibacterial effect of limonene on food-borne pathogens

Abstract

The effects of limonene emulsion and limonene acetone solution on three species of food-borne pathogens were studied. The results of the agar diffusion test indicated that the order of the antibacterial effect on Yersinia enterocolitica was ofloxacin (positive control) > 500 μL/L limonene acetone solution > 5000 μL/L limonene acetone solution > limonene emulsion > 50 μL/L limonene acetone solution > acetone (solvent control), with the inhibition zone diameters of 46.8, 32.2, 27.4, 17.1, 14.5, 9.2 mm, respectively. Except the positive control, the most effective one on Staphylococcus aureus was 50 μL/L limonene acetone solution (the inhibition zone diameter was 30.3 mm). The inhibition zones of limonene acetone solution and acetone to Listeria monocytogenes were similar, while there was no inhibition zone of limonene emulsion, which indicated that it was acetone but not limonene that had the antibacterial activity to L. monocytogenes. The tube dilution test showed that limonene was effective to Y. enterocolitica and S. aureus, but un-effective to L. monocytogenes. Limonene acetone solution showed a higher antibacterial activity with lower values of minimal inhibitory concentration and minimal bactericide concentration than limonene emulsion. Among the three selected food-borne pathogens, Y. enterocolitica was the most sensitive one to limonene, followed by S. aureus and L. monocytogenes.