Abstract: Pseudomonas fluorescence SBW25 is a specific spoilage organisms (SSOs) that plays a leading role in the spoilage of salmon. Salmon meat and sterile fish sauce were chosen as growth media for Pseudomonas fluorescence. The modified Gompertz equation and Belehradek equation were used for fitting kinetic models to predict the growth of P. fluorescence SBW25 at different temperatures. At the same time, the impact of protease activity in sterile fish juice on the growth kinetic parameters was explored, and the applicability of the models was evaluated. Results showed that the coefficients of determination (R2) of the modified Gompertz equations for shelf life prediction at all temperatures tested were up to 0.999, suggesting that the modified Gompertz model is suitable to describe microbial growth in salmon and sterile fish sauce. The maximum specific growth rate (μmax) increased and the lag phase of growth was shortened with the temperature increasing for both media. The R2 values of the Belehradek models between temperature and the square root of μmax and lag phase duration in sterile fish sauce were up to 0.930 3 and 0.988 7, respectively, which were much higher than those in fish meat. In sterile fish sauce, protease activity and μmax at the same growth phase showed the same trend of change. The degree of deviation and accuracy of the Belehradek equation for sterile fish sauce at different temperatures were close to 1.00. The Belehradek model for SSOs growth in sterile fish sauce could reflect the shelf life of salmon at different temperatures.

Key words: salmon, specific spoilage organisms, Pseudomonas fluorescence, shelf life, protease activity