Growth behavior comparison of Listeria monocytogenes between Type strains and beef isolates in raw beef.

This study was conducted to compare the growth parameters of Listeria monocytogenes between beef isolates and Type strains in raw beef. Beef was artificially inoculated with 3 Log CFU/g levels and growth was measured during storage at various temperatures (5-25 °C) using conventional plating methods. The R2 value for lag time (λ) and specific growth rate (μ) were determined using modified-Gompertz model, which were greater than 0.98 at all storage temperature except at 5 °C. B f , A f , and RMSE showed acceptable ranges, showed that the models are suitable for the modeling the growth of L. monocytogenes. At all temperatures, the λ of L. monocytogenes beef isolates was shorter than that of the L. monocytogenes Type strains, and the μ of beef isolates was higher than that of Type strains. These results showed that growth pattern prediction of beef inoculated with L. monocytogenes beef isolates gives more actual results than with Type strains.