Commercial forced-air precooling of strawberries: A temperature distribution and correlation study

Forced-air precooling of strawberries is rarely ideal due to the non-uniform cooling rate inside precooling facilities and the simple heuristics used to select precooling duration. The aim of this work was to investigate the product temperature distribution during commercial forced-air precooling of strawberries, quantify the relationship between the ambient and product temperature and assess precooling durations. Our field studies showed that the half-cooling time (HCT) on the inside of precooling tunnels is approximately twice the HCT on the outside, facing the incoming air, but is relatively constant along the length of the tunnel and vertically within pallets. The HCT on the outside of the tunnel is strongly correlated to the HCT on the inside, enabling temperature predictions from a limited number of sensors. Temperature variations of up to 7 °C were observed at the end of precooling, suggesting that precooling should be extended in some instances to improve uniformity.