Cooling Tunnel System for Laboratory-Based Postharvest Precooling Trials

Chilling injury (CI) affects up to 33% of globally traded postharvest commodities, yet the influence of precooling conditions on CI susceptibility remains largely unexplored. This is likely due to the inherent complexity and variability of commercial operations. This study introduces a novel methodology to systematically evaluate precooling-CI interactions under controlled laboratory conditions. The approach is grounded in commercial precooling characteristics and comprehensive cold chain CI evaluation protocols. A laboratory forced-air cooling system was developed, consisting of wind tunnels installed in existing cold rooms to replicate commercial precooling airflow speeds and cooling rates. The system successfully reproduced commercial precooling conditions and induced statistically significant, differentiable CI responses in citrus trials. the methodology provides researchers with a reproducible platform for investigating precooling optimisation strategies and CI mitigation for both citrus and other fruit types, with potential applications in postharvest technology development and supply chain optimisation. Key methodological components include: Characterisation of commercial precooling conditions to establish realistic design parameters Development and application of a laboratory-scale wind tunnel precooling simulator Chilling injury evaluation protocol for precooling protocol assessment