Survey on antimicrobial effects of olive oil and extract on pathogenic bacteria using Taguchi methodology

Antibacterial activity has recently been demonstrated in olive products. This antibacterial effect was correlated with the presence of different substances such as oleuropein. In present work antibacterial activity of different olive products was examined and their oleuropein content were determined. Also, the effect of different factors on antimicrobial activity were assayed by Taguchi methodology. Three varieties of fruit, leaves, and unrefined olive oil were purchased from Roodbar in Guilan province and ethanolic extract was examined. Antimicrobial activity of leaves and olive fruits were performed by disk and well diffusion, and pore plating method. Also, according to Taguchi methodology, effect of different factors such as incubation time, bacterial suspension concentration, type of bacteria, and type of extracts on antibacterial activity were evaluated. HPLC was performed to measure the oleuropein content at the Science and Technology Park of Guilan. Data analyzes were performed by using Minitab software. Leaves, fruits, and oil olive extract had significant impact on E. coli, S. aureus, and P. aeruginosa. Data analysis showed that exposure time and type of extracts had a significant antimicrobial effect on pathogen bacteria. Also, fruit extract had greater antimicrobial activity than olive oil. Eventually, S. aureus was (susceptible) than E. coli and P. aeruginosa to olive extracts. In current study, HPLC confirmed oleuropein as main antimicrobial ingredient of olive at 2.63ppm. In this study, antimicrobial activity of olives products against E. coli, S. aureus, and P. aeruginosa demonstrated that different extracts of olive have potential for preparation herbal medicines.