Modeling In-Shell Pasteurization of egg by computational fluid dynamics (CFD) technique

Egg contamination by Salmonella enteritidis is one of the most important causes of foodborne gastroenteritis throughout the world and the common method which can be used to inactivate this bacteria is pasteurization. In this study, the pasteurization of intact egg was mathematically modelled using a CFD technique. The results were compared with experimental data and it was found that the model could reasonably forecast the temperature of egg during pasteurization (R2>0.98). The model showed that in order to predict the temperature variation of the slowest heating zone (SHZ) with higher accuracy, it is necessary to to incorporate the influence of natural convection currents induced by the hot eggshell walls in the pasteurization process. Results indicated that the SHZ keeps moving during pasteurization and eventually stays in a region that is about 25% of the egg height from the bottom after 300 s of heating. These results also show that the time required to reduce the Salmonella enteritidis population in cold point of eggs to 5D is approximately 28 minutes. This model could serve as an important tool in better understanding of the pasteurization process, choosing the best process parameters and facilitate process optimization of intact egg pasteurization towards industrial implementation