Ambient loading - increasing citrus cold chain efficiency

South Africa is an important producer and exporter of fresh citrus fruit, which is shipped across the world over large distances. Projections indicate that future citrus production will increase significantly, resulting in increased stress on fruit precooling facilities. Additionally, international phytosanitary requirements are expected to become progressively more stringent, further increasing the cooling demand in precooling facilities. Ambient loading is a cold chain approach whereby palletized fruit bypass a precooling facility and are loaded warm into the reefer container, after which they are cooled within the container. This approach is a highly valued solution toward reducing stress on facilities, costs and waiting times, but has only been tested in combination with Supervent telescopic cartons. The aim of this study was to examine the feasibility of the ambient loading strategy in combination with Opentop cartons. The work performs a detailed analysis of the resulting temperature characteristics inside a reefer container during shipping. Fruit in the containers reached 3°C within 5-6 days. Although this was within acceptable tolerances, more cooling heterogeneity was observed in one of the containers, which was attributed to an inadequate airflow distribution. Future improvements of ambient loading may lie in improving the design of void plugs to minimize regions that can allow airflow to bypass the packaged fruit.