Investigation the antimicrobial activity of nisin and lysozyme on Listeria monocytogenes and Escherichia coli at different pH and at 24 ° C

In order to prevent or inhibit the growth of pathogenic objects and factors of food spoilage, great deal of research has been done by using natural preservatives and currently is performed. This study has been done to investigate the effect of different concentrations of lysozyme and nisin on the growth rate of the bacteria Escherichia coli and Listeria monocytogenes and also  determination of MIC and MBC of this combinations on these bacteria.In this study, various concentrations of lysozyme and nisin was set in form of alone concentration and in combination concentration (0, 19.53, 39.06, 78.13, 156.25, 312.5, 625, 1250, 2500, 5000) in vitro conditions and pH 5.5, 6, 6.5, 7, 7.5 and 8.These actions was done in microdilution method at 24 ° C and reading the combined effect on the growth of bacteria was performed by using ELISA reader.The results showed that lysozyme is less effective on the E. coli and nisin have less effective on the L.monocytogenes. The combined use of lysozyme and nisin at low pH was decreased MIC.