In this study the antimicrobial activity of Olive Leaf Extracts (OLE) was screened against five gram-positive and five gram-negative bacteria. The antimicrobial activity was evaluated using disc diffusion and microdilution methods. The diameters of inhibition zones of the olive leaf extract were observed 13.33±2.08 mm against S. typhimurium and 21.67±1.53 mm against B. cereus. There was a similarity between the inhibition zones of olive leaf extract and Gentamicin discs against S. typhimurium, P. vulgaris and P. aeruginosa. While Minimum Inhibitory Concentrations (MIC) of olive leaves extract against, L. monocytogenes, E. coli O157, E. sakazakii and P. aeruginosa was â¥32 mg mL-1, the MIC against the other bacteria (B. cereus, S. aureus, E. faecalis, P. vulgaris, E. coli, S. typhimurium) that used in this study was â¥16 mg mL-1. Itâs considered that some other works should be conducted about using olive leaf extract in food industry as a natural antimicrobial food additivie as well as medicine and pharmaceutical industry.
