Microbial growth kinetics model of specific spoilage organisms and shelf life prediction for tilapia

A series of experiments had been carried out to develop and validate the growth kinetics model of specific spoilage organisms for predicting the microbial quality and remaining shelf life of cultured tilapia stored aerobically in cold temperature. The results from microbiological behaviors analysis, organoleptical quality and TVBN evaluation identified Pseudomonas spp. as special spoilage organisms of tilapia stored at 0 - 15℃. At the end of shelf life, the average number of Pseudomonas spp. was 7.70 ? 0.11 log10cfu?g^-1 at temperatures 0,5, 10 and 15℃. The kinetics models of Pseudomonas spp. had been developed and the results showed growth dynamics of this organism under 0 - 15 ℃ could be well described by a Gompertz type model. The temperature had no significant effect on Nmax （maximum cell concentration）, the average value of Nmax was determined to be 8.85 ? 0.18 log10cfu? g^-1 under those four temperatures. The temperature dependence of Pseudomonas spp. kinetic parameters - μmax（ maximum specific growth rate） and Lag （lag phase） were modeled using Belehradek model. The correlation regression showed could finely describe the influence of temperature on growth. Validation of built kinetic models was preferred by comparing with experimental development of Pseudomonas spp. grown on tilapia at temperatures 3℃,8 ℃. Bias and accuracy factors were used as comparison indices and range from 0.97 to 1.01 and from 1.02 to 1.04, respectively. The results derived from validation showed that the developed models could finely predict the growth kinetic of Pseudomonas spp. at 0 - 15 ℃. Basic errors between predicted shelf life and real shelf life were 3.47% and - 7.91% at 3, 8℃ respectively, it suggested microbial growth models built in our research were valuable for rapid and realistic prediction of the microbial quality and remaining shelf life of cultured tilapia stored aerobically from 0 to 15℃.