Effect of Boiss Zataria Multiflora Essential Oil on Escherichia coli and Listeria monocytogenes Inoculated into Ground Silver Carp (Hypophthalmichthys molitrix)

Background and Escherichia coli is a common cause of food poisoning. After entering the body, toxins will release in the intestinal. Toxin derived from this bacterium can damage the intestinal mucosal and cause severe abdominal pain and diarrhea. Listeria monocytogenes in animals and humans causes a serious infection called listeriosis that could be transferred to humans through contaminated food such as cheese, raw vegetables, salads and fish. This study aimed at evaluating the effect of essential oil of Boiss Zataria multiflora on the behavior of E. coli and L. monocytogenes in ground silver carp (Hypophthalmichthys molitrix) stored at temperature C ° 4. The samples were inoculated separately by E.coli and L. monocytogenes at 4.5 and 4.6 log CFU/gr, respectively. Then, treatments of B. Zataria multiflora were prepared in two concentrations of 0.8% and 1.2%. All samples in both treatment and control group were stored at refrigerator temperature for 72 hr. The number of E.coli and L. monocytogenes were counted daily by cultivation on the Ecc Chromagar liquid and listeria selective chromagar medium. We observed significant antimicrobial effect in 1.2% concentration of B. Zataria multiflora, which was also able to reduce E. coli after 48 hours. This treatment had a high bactericidal effect, since no bacterial colonies were isolated at 48 and 72 hours. The studied concentrations of B. Zataria multiflora, showed inhibitory effects on L. monocytogenes. B. Zataria multiflora was found to have bactericidal activity against E.coli while this activity was not considerable against L. monocytogenes.