From the earliest days of European settlement in North America, the colonies were dependent on imported food. When they eventually developed successful agricultural systems, food was shipped abroad, and over time food became one of America’s most important exports. Historically, the worst bottleneck—and the greatest expense—in the transportation of food by ship was loading and unloading the cargo. This transfer was a long, slow process involving thousands of workers, so imported food was more costly, and perishable items, such as fresh fruits and vegetables, often spoiled in transit.