Numerical modelling of the temperature increase in frozen food packaged in pallets in the distribution chain

Frozen food can undergo temperature rise essentially during handling processes which are the weakest links of the cold chain: delivery, loading or unloading operations and temporary storage where pallets are generally handled in an ambience above 0°C. In this study, the temperature rise in a pallet is investigated numerically and experimentally. A three-dimensional finite-volume heat transfer model is developed using Phoenics Computational Fluid Dynamics (CFD) software. Food temperature within the pallet is predicted as a function of time of exposure, ambient conditions, product initial temperature, palletization and thermal characteristics of products and packaging. The experiments are carried out with packaged frozen fish pallets placed on a closed or open dock. The temperatures are recorded, at different levels in pallets over 25- to 85-min periods. The model shows good agreement with experimental results.