Growth rate and osmolyte accumulation of L. monocytogenes were measured at the varying concentrations of NaCl. L. monocytogenes accumulated glycine betaine and glutamate intracellularly when grown under osmotic stress by NaCl, and the amounts of them increased as the concentration of NaCl was increased. They were 685 and 345 nmol/㎎ protein, respectively, when grown in the BHI supplemented with 4% NaCl. In order to inhibit L. monocytogenes effectively, both NaCl and Morus alba L. leaf extract were supplemented in TSB, and antibacterial effect of those supplements on L. monocytogenes was tested. Growth of G. monocytogenes grown in TSB supplemented with 2% NaCl and 100 ppm M. alba leaf extract decreased by 10 times in CFU/㎖ unit comparing to the growth of control. When grown in TSB, supplemented with 2% NaCl plus 500 ppm M. alba leaf extract and 2% NaCl plus 1,000 ppm M. alba leaf extract, growth of L. monocytogenes decreased by 10^5 and 10^8 times in CFU/㎖ unit, respectively.