Quality changes of air-packaged chicken meat stored under different temperature conditions and mathematical modelling for predicting the microbial growth and shelf life

The purpose of the present study was to investigate the changes in bacterial flora including the number of Pseudomonas spp., total viable count, lactic acid bacteria and Enterobacteriaceae and to predict the shelf life of air-packaged chicken meat stored at different storage temperatures (0 degrees C, 4 degrees C, 10 degrees C, and 15 degrees C). The correlation coefficient between Pseudomonas spp. count, total viable count, total volatile basic nitrogen, sensory evaluation scores, and pH showed that Pseudomonas spp. is a specific spoilage organism (Nychas, Skandamis et al.) (R-2> .940, p<.01). The Gompertz model was fitted well to the experimental data (p<.001, R-2> .989) and the MSE values were relatively small. The specific growth rate of Pseudomonas spp. in the chicken meat was 0.096, 0.122, 0.287, and 0.528/hr at 0 degrees C, 4 degrees C, 10 degrees C, and 15 degrees C, respectively. The lag phase was 74.3 hr, 25.2 hr, 14.8 hr, and 2.7 hr at 0 degrees C, 4 degrees C, 10 degrees C, and 15 degrees C, respectively. The Arrhenius equation was used as a secondary model to describe the effect of temperature on the maximum growth rate of Pseudomonas spp. in the poultry. The activation energy for growth of Pseudomonas spp. in the chicken meat was 74.0 kJ/mol. Finally, an exponential equation was used for shelf life prediction of poultry meat. The Gompertz model satisfactorily predicted the growth of Pseudomonas spp. as the specific spoilage organism in the air-packaged chicken meat stored under different temperature conditions. Practical applicationsThere is no significant difference between experimental and predicted data by the model for air-packed poultry meat, so the data tested in laboratory media could be easily used in real food after the mathematical process using the Gompertz model and it can be used to control the potential hazard in food and quality control.