INHIBITORY EFFECT OF GARLIC EXTRACT ON THE GROWTH OF SALMONELLA TYPHIMURIUM AND SHIGELLA DYSENTERIC

Introduction: Nowadays, using plant extracts as antimicrobial additives has got an important role in maintaining the quality of food products. Garlic is one of the plants the antimicrobial effect of which has been proved by biochemical investigation. The aim of this study was to assess the effect of different concentrations of garlic powder extract and garlic tablet extract on Salmonella typhimurium and Shigella dysenteric in the same conditions. Methods: To do this investigation, fresh garlic from Hamadan and garlic tablets from Kowsar Pharmacy Company was provided. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of garlic Powder extract and garlic tablet extract on the growth of two micro-organisms were tested through tube standard method. Results: The MIC of garlic Powder extract on the tested microorganisms was 12.5 mg/ml and the MBC was 25 mg/ml, while the MIC of garlic tablet extract was 40mg/ml and the MBC was 80 mg/ml. According to these results, the inhibitory effect of the extract of the garlic (GP &GT) on both bacteria was similar, but the inhibitory effect of the garlic powder was much more than that of garlic tablet (3.28 times), either on Salmonella or Shigella. Conclusion: Noticing the findings of the present study and other related reports in this field, the application of this extract in food preservative systems is useful for inhibiting food contaminations.