INHIBITION OF FOODBORNE PATHOGENS AND SPOILING BACTERIA BY ESSENTIAL OIL AND EXTRACTS OF ERIGERON RAMOSUS (WALT.) B.S.P. ATIQUR RAHMAN 1,2 and SUN CHUL KANG 1,3 1 Department of Biotechnology Daegu University Kyoungsan, Kyoungbook 712-714, Korea 2 Department of Applied Chemistry and Chemical Technology Islamic University Kushtia 7003, Bangladesh Accepted for Publication January 5, 2008 ABSTRACT The antibacterial potential of essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P. was evaluated. Thirty-one components repre- senting 95.3% of the total oil were identified, of which b-caryophyllene (24.0%), a-humulene (14.5%), 1,8-cineole (9.0%), eugenol (7.2%), globulol (7.1%), caryophyllene oxide (5.2%), d-cadinene (5.0%), a-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 deter- mination test against 14 (seven gram-positive and seven gram-negative) food- borne bacteria. The essential oil (5 mL/mL, corresponding to 1,000 ppm/disc), methanol extract and its different organic subfractions (7.5 mL/mL, corre- sponding 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 mg/mL. 3 Corresponding author. TEL: +82-53-850-6553; FAX: +82-53-850-6559; EMAIL: sckang@ daegu.ac.kr Journal of Food Safety 29 (2009) 176–189. © 2009, The Author(s) Journal compilation © 2009, Wiley Periodicals, Inc. 176