Investigation on the antimicrobial effect of caseinate edible film containing the essential oil of Zataria multiflora

Antimicrobial effect of caseinat edible film containing the essential oil of Zataria multiflora Bioss was investigated against tow gram-negative bacteria named Salmonella typhymurium (ATCC14028)، Escherichia coli O157: H7 (ATCC35218) and agram-positive bacteria Staphylococcous aureus (PTCC1431). The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the tested essential oil were determinate by using a broth dilution susceptibility test at 6 different concentrations (125، 250، 500، 1000، 2000 and 4000 ppm). The essential oil from Avishan Shirazi (Zataria multiflora Bioss) was most effective against S. aureus، the MIC and MBC values in the presence of E. coli O157: H7 and S. typhymurium were 500 for both of them. The antimicrobial effect of caseinate film was studing using disk diffusion method. Our result showed that the larger inhibitory diameter was belonged to S. aureus (mean=25. 17mm) mean diameters of inhibitory effect for S. typhymurium and E. coli O157: H7 were 15. 20 and 17. 62 mm respectively.