Abstract:Some natural spices have demonstrated the ability to reduce microbe populations.Evaluating the effects of natural spices on E.coli O157：H7 will inform our ability to use natural spices to improve food safety.Natural spices including star anise，clove，cinnamon，fennel seeds，mustard，Sichuan pepper，pepper，and bay leaf from different areas，were used in this study.Their bactericidal effects at optimized concentrations，and the effect of ethanol extraction duration on potency were investigated using E.coli O157：H7 as a target microbe.Regional effects on the efficacy of each spice was also analyzed.The spices had unique，characteristic killing capabilities toward E.coli O157：H7 （p＜0.05）.Clove had the most potent bactericidal action，reducing the E.coli O157：H7 population by at least 5 lg （CFU/mL）in 1 h using a 9.1% by volume extract.Star anise was the next most potent.Three kinds of mustard extract did not display high bactericidal potency toward E.coli O157：H7.The average reduction in E.coli O157：H7 population over 1 h using 50% extract by volume was 2.47 lg（CFU/mL）.The region where they were grown may affect the bactericidal action of natural spices.Significant variations by region were seen with fennel seeds，cinnamon，and star anise（p＜0.05）.