From the moment a fruit or vegetable was harvested from its parent plant, it underwent a process of aging and eventual decay known as senescence. Senescence was marked by two main activities: respiration and transpiration.
During normal respiration, plants converted oxygen and carbohydrates (acids and sugars) into water, carbon dioxide, and heat-all three of which were emitted from the plant. The mother plant replaced used carbohydrates in the produce (fruits or vegetables) still connected to it; once the produce was harvested, of course, those nutrients could not be replaced. Respiration continued post-harvest until the sugars stored in the produce no longer sustained it; after that, the produce broke down and lost quality.
Transpiration was the process of losing water. Most produce contained 80% to 95% water at harvest; however, as with respiration, the mother plant could not replace lost water post-harvest. As fruits and vegetables lost water, they lost weight, cell structure, firmness, and appearance-in other words, they began to shrivel and decay. After a water loss of 5% to 10%, produce wilted, shrank, and became unusable and unsalable. Players in the fresh produce global supply chain were always in a race against senescence. While the rate of senescence varied from product to product, its onset was immediate after harvest and rarely allowed more than two weeks to deliver a product from farm to fork.
Growers harvested most fruits intended for export or a significant journey (e.g., California to Boston) well before they ripened naturally. For example, tomatoes and bananas were typically harvested when they were still completely green. Early harvesting deprived the fruit of its natural ripening process and had a negative effect on the taste, nutritional value, and quality. If growers could slow or halt the senescence rate of produce in a safe, sustainable way without altering taste or appearance, then they could significantly change their shipping methods, shipment timing, and geographical reach. They could, for example, choose slower and more affordable transportation methods than those currently in use.