4 ethylcatechol

All experiments were conducted at 37 °C in Luria-Bertani (LB) medium, which was used to culture E. coli O157:H7 (ATCC 43895, EDL933 strain) and three laboratory E. coli K-12 strains (MG1655, BW25113, and TG1). To culture E. coli O157:H7/pCM18 tagged with green fluorescent protein, LB broth containing 300 μg/ml of erythromycin was used to maintain the pCM18-GFP plasmid. Bacterial cells were initially streaked from −80 °C glycerol stock on LB plates, grown on plates, and then were cultured from a fresh single colony in LB broth. For phenotypic assays, overnight cultures (stationary phase cells) were inoculated again in LB broth at an initial turbidity of 0.05 at 600 nm. The 83 essential oils (Supplementary Table S1) were obtained from Berjé (Bloomfield, NJ, USA) or Jin Aromatics (Anyang, Gyeonggi Province, Korea). Other chemicals (guaiacol, 4-ethylcatechol, thymol, 2-methoxyhydroquinone, vanillin, carvacrol, methyl eugenol, 2-methoxy-4-propylphenol, isoeugenol, 4-ethylguaiacol, and eugenol) were purchased from Sigma-Aldrich (St. Louis, USA). For cell growth measurements, turbidity was measured at 600 nm using a spectrophotometer (Optizen 2120UV, Mecasys, Korea).