Investigation of antimicrobial effect of some plant extracts on foodborne pathogens

Keywords: Rosemary, Garlic, Foodborne Phatogens, Antimicrobial Effect In this study garlic and rosemary was studied and inhibitory effects of these spice extracts on foofborne pathogens such as Bacillus cereus, Helicobacter pylori, Sraphylococcus aureus, Cronobacter sakazakiii and Salmonella Typhimurium were investigated. For this purpose, disc diffusion and microdilution methods were used. Analyses for each sample repeated three times and averaged. It was determined that rosemary and garlic extracts had antimicrobial effects for five foodborne pathogens studied, in different ratios. The largest zone was observsd garlic extract with 1/1 ratio on S. aureus with a zone diameter of 30.1 mm; followed by B. cereus, C. sakazakiii, and S. Typhimuriım, H. Pylori respectively. This effect was seen in the 1/8 ratio only for C. sakazakiii. The most sensitive bacteria to the 1000 ppm rosemary extract was B. cereus followed by H. pylori and S. aureus.The most resistant bacteria to the rosemary extract was S.Typhimurium and C. sakazakiii. Antimicrobial effects of garlic and rosemary were compared with commonly used antibiotics such as Cephalexin 30 (Ce30) and Tetracycline 30 (Cl30). As a result, 1/1 ratio of garlic extract showed higher antibacterial effect than CI 30 on all of the existing bacteria with the exception of H. pylori. Te 30 had less effect only on S. aureus and B. ceresus than garlic. In the study, the minimum inhibition concentration (MIC) values of garlic and rosemary extracts, determined by microdilution method, showed differences for each pathogen. The MIC value of the rosemary extract was 62.5 ppm for H. pylori and B. cereus; 250 ppm for S. Typhimurium and 125 ppm for other bacteria. MIC values of garlic extract are; 1/16 for H. pylori, 1/4 for S. aureus and C. sakazakii, and 1/8 for B. ceresus and S. Typhimurium. In order to determine the effect of the oil content on antimicrobial activity, sunflower oil was added to the liquid culture medium and microbial growth was observed. The effect of Tween 20 used for emulsion formation on antimicrobial activity was alsoinvestigated. It was observed oil and tween 20 had antimicrobial effects on S.aureus and S. Typhimurium, at different ratios. It was determined that %20 oil and %1.5 Tween 20 concenration showed a significant effect on S. aureus and S. Typhimurium which are the most resistant to garlic and rosemary extract statiscially showed inhibitor effect.