Risk-based design of aseptic processing of heterogeneous food products

A risk assessment was performed to incorporate uncertainty in food processing conditions to develop a risk-based sterilization process design. The focus of this analysis was uncertainty associated with heterogeneous food products. Quartered button mushrooms were the chosen food product because it represents the most typical type. A model for sterilization of spherical particles was utilized, and each parameter's uncertainty was characterized for use under Monte Carlo simulation. Various particle distributions and fluid types were compared. The output of the model was the required sterilization time to achieve the target sterilization conditions with 95% probability. This value was then used to determine the mean fluid velocity for a given tube length. Finally, the output from the model was analyzed to determine the confidence in output based on uncertainty in the input parameters. The model was more sensitive to variation in particle size distribution than fluid type for power-law fluids. The 90% confidence interval included a holding time range of 1 min. With a 95% confidence level that only 8% of the data will be below the target sterilization conditions, a maximum of 9% of the data were expected to achieve double the target level. The results of such an analysis would be useful for management decisions concerning the design of aseptic food processing operations.