Modeling the Propagation of Salmonella within Bulk Almond Using Discrete Element Method Particle Simulation Technique

QJ Suehr and BP Marks and ET Ryser and S Jeong, JOURNAL OF FOOD ENGINEERING, 293, 110363 (2021).

DOI: 10.1016/j.jfoodeng.2020.110363

Modeling the propagation of bacterial cross-contamination within bulk material is a critical task for validating the microbial safety of the complex post-harvest processing of tree nuts. In this paper, discrete element method (DEM) coupled with a heat transfer modeling was applied to a bacterial cell transfer problem, and the model outputs were translated into the case of bulk almond kernels contaminated with Salmonella in a mixing process. The DEM model was calibrated via a small-scale (0.2 kg) dry transfer experiment with flat rotary drum mixing trials, and validated with medium-scale experimental data (1 kg) in terms of spatial-temporal distribution of the contamination in the bulk material. Thereafter, the DEM model was tested to simulate a large- scale drum mixing simulation (200 kg), which demonstrated its expandability with reasonable bacterial propagation outcomes. This study demonstrated that DEM is an efficient tool for modeling complex bacterial cross-contamination/propagation during bulk food material processing.

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