Modelling the growth of Pseudomonas fluorescens and Candida sake in ready-to-eat meals Original Research Article

Pseudomonas fluorescens and Candida sake were isolated from chilled foods and inoculated into ready-to-eat meal models and stored at 5, 10, 15, and 20 °C. The growth of both P. fluorescens and C. sake and sensory quality of the models were monitored during the storage up to when spoilage occurs. The counts of P. fluorescens increased (P<0.05) during the storage periods up to 168, 120, 72, 60 h storage at 5, 10, 15, and 20 °C, respectively. The lag time for P. fluorescens in the models stored at low temperature was longer than that at high temperature. For models inoculated with P. fluorescens, it was found that there was no significance difference in overall acceptability among the samples during the storage at 5, 10, and 15 °C. Models inoculated with C. sake showed no significance difference for overall acceptability at 5, and 15 °C, but there was a significant difference (P<0.01) for models stored at 10 °C. The maximum population density (A) for P. fluorescens and C. sake ranged from 11.18 to 11.96 log CFU/g and 9.02 to 10.38 log CFU/g, respectively. Statistical analysis showed that the μm values for both P. fluorescens and C. sake increased (P<0.05) with increasing the temperature of storage. The length of the lag phase for both P. fluorescens and C. sake was affected by temperature, with the duration of the lag phase decreasing with increasing temperature. The secondary model could be used to describe (r2>0.974) the growth of each organism for these storage time (0–384 h) and temperature (5–20 °C).