Growth Prediction of Aeromonas hydrophila in Fresh Cheese Stored at 4°C

The aim of this study was to determine the behavior of Aeromonas hydrophila in “Minas Frescal” cheese during storage at 4°C, 8°C and 12°C using a regression model and to predict the development of this microorganism during 24 days of storage. Cheese was vacuum-packed and then stored at the study temperatures. A. hydrophila and aerobic heterotrophic psychrotrophic bacteria (AHPB) were quantified during storage, water activity (wa) and pH were analyzed. Then, the microbiological counts were submitted to regression analysis and the averages were analyzed using Pearson's correlation with the wa and pH parameters. Results showed that A. hydrophila developed significantly at refrigeration temperatures, with high growth rates at 4°C and 8°C, in contrast to those observed at 12°C. There was a slight variation in the wa and pH results and AHPB presented good performance at all the temperatures analyzed. The models obtained fitted better at a temperature of 4°C and were able to predict the growth of A. hydrophila with a model fit of 90% (p<0.001). In conclusion, the model obtained for predicting the growth of A. hydrophila at 4°C was accurate up to 13 days after the product was manufactured, showing that temperature control was crucial for maintaining product quality; wa and pH were not parameters for quality control.