Exploring a new heterogeneity index to quantify the variation of cooling rates within systems that undergo the forced-air cooling process.

Forced-air cooling is a commonly used pre-cooling process that forces refrigerated air through a stacked pallet of produce, rapidly removing the field heat in preparation for storage and transport. Cooling rates can vary spatially throughout the pallet due to uneven airflow distribution and the relative proximity to the inlet of refrigerated air. This heterogeneity in pre-cooling processes may result in significant differences in quality and shelf life at the end of the cold chain. Therefore in assessing pre-cooling performance, in addition to assessing average cooling rate (through 1/2 cooling or 7/8 cooling time), a robust heterogeneity metric is required to quantify the variability in a cooling process, and hence compare different systems. The aim of this work is to develop this heterogeneity index. The new method is illustrated through application to polylined kiwifruit inside of a modular bulk package.