Authors : S.S. Saei Dehkordi , S.M. Razavi Rohani , H. Tajik , M. Moradi and J. Aliakbarlou
Abstract: The antibacterial efficacy of unheated lysozyme (L) and Heat-Treated Lysozyme (HTL) at 62, 72 and 80�C, separately and in combination with Zataria multiflora Boiss. essential oil (Z.EO) on E. coli O157:H7 and S. aureus at different pH (5, 6 and 7) and NaCl concentrations (0.5, 1.5 and 3%) was studied. A micro-broth dilution assay was applied to define the Minimal Inhibitory Concentrations (MICs). The inhibitory action of L on S. aureus was increased along with pH deduction and NaCl enhancement, whereas E. coli O157:H7 wasn�t inhibited up to 1024 �g mL 1 at similar circumstances. Both bacteria were inhibited by HTL (at 72 and 80�C) at NaCl 0.5%, but at 1.5% of NaCl concentration, the inhibition was stopped. However, the inhibitory activity of HTL was greater than L. Z.EO was effective against both bacteria and inhibition was stronger at lower pH and higher NaCl concentrations. MICs of L and HTL combined with Z.EO were decreased. Enhancement of Z.EO concentrations was led to more prominent inhibition, whereas, by increasing NaCl concentration, inhibition was reduced considerably. The lowest MICs of L and HTL were achieved by increase of Z.EO to 300 �g mL 1 along with decrease the pH and NaCl to 5 and 0.5%, respectively.
S.S. Saei Dehkordi , S.M. Razavi Rohani , H. Tajik , M. Moradi and J. Aliakbarlou , 2008. Antimicrobial Effects of Lysozyme in Combination with Zataria multiflora Boiss. Essential Oil at Different pH and NaCl Concentrations on E. coli O157:H7 and Staphylococcus aureus. Journal of Animal and Veterinary Advances, 7: 1458-1463.