Effects of Turkish spice extracts at various concentrations on the growth of Escherichia coli O157:H7

The antimicrobial activities of the extracts of seven spices (cumin, Helichrysum compactum Boiss (HC), laurel, myrtle, oregano, sage and thyme) were examined in their capacity to inhibit the growth of Escherichia coli O157:H7. Spices were fractionated by the extraction method to obtain a methanolic fraction. Of the spices tested, thyme showed promising results by inhibiting growth both in paper disc assay and agitated liquid culture assay. Antibacterial effects of tested spices extracts vary related to concentrations. Thyme and oregano showed higher activity than the others. It was also found that laurel and HC markedly stimulated the growth of E. coli O157:H7. Statistically, important variations were found among the inhibitory effects of spice extracts. This study has shown that E. coli O157:H7 inhibition by spice extracts may be of use in the field of food preservation. © 2002 Elsevier Science Ltd. All rights reserved.