EN
Thermal resistance of L. monocytogenes strains that had been isolated from raw milk was determined in BHI broth. L. monocytogenes 1 were isolated from collected milk and L. monocytogenes 2 directly from a cow udder. Thtj strains at concentration of approximately lxl(r cell ml'1 were heated at 55°, 60° and 65°C for various periods of time. Decimal reduction times for L. monocytogenes 1 were D55 = 37.45 min, D60 = 2.63 min., Dć5 = 0.24 min. and for L. monocytogenes 2 the data were 9.73, 0.98 and 0.17 respectively. Z-values were 4.79 and 5.56° C, respectively. The reports that L. monocytogenes can survive pasteurization temperature have not been confirmed.