INHIBITION OF FOODBORNE PATHOGENS AND SPOILING BACTERIA BY ESSENTIAL OIL AND EXTRACTS OF ERIGERON RAMOSUS (WALT.) B.S.P.

Abstract

ABSTRACT The antibacterial potential of essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P. was evaluated. Thirty‐one components representing 95.3% of the total oil were identified, of which β‐caryophyllene (24.0%), α‐humulene (14.5%), 1,8‐cineole (9.0%), eugenol (7.2%), globulol (7.1%), caryophyllene oxide (5.2%), δ‐cadinene (5.0%), α‐copaene (4.9%) and widdrol (2.0%) were the major components. The antibacterial activity of essential oil and methanolic extracts of E. ramosus was determined in vitro using the agar diffusion method and minimum inhibitory concentration determination test against 14 (seven gram‐positive and seven gram‐negative) foodborne bacteria. The essential oil (5 µL/mL, corresponding to 1,000 ppm/disc), methanol extract and its different organic subfractions (7.5 µL/mL, corresponding to 1500 ppm/disc) of E. ramosus displayed a great potential of antibacterial activity against all gram‐positive bacteria: Staphylococcus aureus (ATCC 6538 and KCTC 1916), Listeria monocytogenes (ATCC 19116, ATCC 19118, ATCC 19166 and ATCC 15313) and Bacillus subtilis ATCC 6633 and four gram‐negative bacteria: Pseudomonas aeruginosa KCTC 2004, Enterobacter aerogenes KCTC 2190 and Escherichia coli (0157:H7 ATCC 43888 and ATCC 8739). The zones of inhibition of different concentrations of essential oil and methanolic extracts against the tested bacteria were found in the range of 10.1∼22.3 mm, and MIC values were recorded between 62.5 and 500 µg/mL.PRACTICAL APPLICATIONSThe use of essential oil and organic extracts of Erigeron ramosus (Walt.) B.S.P. as antibacterial agents will be suitable for applications on the food industry as natural preservatives or flavoring to control foodborne pathogens. They can be used as growth inhibitors of Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes and Pseudomonas aeruginosa, some important foodborne pathogens and spoiling bacteria. The main reason for their suitability is their natural origin, which consumers find comforting and which is beneficial for the environment, and the very low risk that pathogens will develop resistance to the mixture of components that make up the oil and extracts with their apparent diversity of antibacterial mechanisms. These beneficial characteristics could increase food safety and shelf life.