Excerpts from the report: This research was undertaken to explore engineering problems of forced-air precooling of oranges, grapefruit, tangerines, and tangelos and its biological effects on the fruit. The general objective was to determine the commercial potential of cooling the fruit by forcing air at temperatures substantially below the fruit's freezing point through the void spaces in bulk lots of fruit. Specifically, the work was aimed at optimizing the rate of airflow and air temperature for maximum efficiency and effectiveness in forced-air precooling. Two less significant objectives were to compare cooling of place-packed citrus with that in random-filled bulk boxes and cooling rates of citrus in different types of shipping containers.