Modeling the Growth of Six <i>Listeria monocytogenes</i> Strains in Smoked Salmon Pate

In this study, the growth of six L. monocytogenes strains isolated from different fish products was quantified and modeled in smoked salmon pate at a temperature ranging from 2 to 20 degrees C. The experimental data obtained for each strain was fitted to the primary growth model of Baranyi and Roberts to estimate the following kinetic parameters: lag phase (lambda), maximum specific growth rate (mu(max)), and maximum cell density (N-max). Then, the effect of storage temperature on the obtained mu(max) values was modeled by the Ratkowsky secondary model. In general, the six L. monocytogenes strains showed rapid growth in salmon pate at all storage temperatures, with a relatively short lag phase lambda, even at 2 degrees C. The growth behavior among the tested strains was similar at the same storage temperature, although significant differences were found for the parameters lambda and mu(max). Besides, the growth variations among the strains did not follow a regular pattern. The estimated secondary model parameter T-min ranged from -4.25 to -3.19 degrees C. This study provides accurate predictive models for the growth of L. monocytogenes in fish pates that can be used in shelf life and microbial risk assessment studies. In addition, the models generated in this work can be implemented in predictive modeling tools and repositories that can be reliably and easily used by the fish industry and end-users to establish measures aimed at controlling the growth of L. monocytogenes in fish-based pates.