Predictive modeling of the shelf life of fish under nonisothermal conditions

The behavior of the natural microflora of Mediterannean gilt-head seabream (Sparus aurata) was monitored during aerobic storage at different isotherma l conditions from 0 to 15 degreesC. The growth data of pseudomonads, establ ished as the specific spoilage organisms of aerobically stored gilt-head se abream, combined with data from previously published experiments, were used to model the effect of temperature on pseudomonad growth using a Belehrade k type model. The nominal minimum temperature parameters of the Belehradek model (T,,,) for the maximum specific growth rate (mu (max)) and the lag ph ase (t(lag)) were determined to be -11.8 and -12.8 degreesC, respectively. The applicability of the model in predicting pseudomonad growth on fish at fluctuating temperatures was evaluated by comparing predictions with observ ed growth in experiments under dynamic conditions. Temperature scenarios de signed in the laboratory and simulation of real temperature profiles observ ed in the fish chill chain were used. Bias and accuracy factors were used a s comparison indices and ranged from 0.91 to 1.17 and from 1.11 to 1.17, re spectively. The average percent difference between shelf life predicted bas ed on pseudomonad growth and shelf life experimentally determined by sensor y analysis for all temperature profiles tested was 5.8%, indicating that th e model is able to predict accurately fish quality in real-world conditions .