Sorting for Defects and Visual Quality Attributes

Publisher Summary This chapter discusses the importance of the sorting operation to postharvest supply chains and also mentions visual quality attributes. The sorting operation must be viewed in the context of overall postharvest supply chains. It is important to understand how cultural practices and uncontrolled inputs, such as weather, cause variation of quality in products that enter the packing house. Likewise, at the time of shipping, it is important to be able to predict the quality of shipments as they progress through the rest of a postharvest supply chain. A major function of a packing house is to transform the highly variable product received from the harvesting operation into uniform lots of product for shipments that comply with the requirements of the buyer. The importance of the sorting operation cannot be overstated, since variations in this operation will affect returns for most other parts of postharvest supply chains. The ability of humans to perceive a visual image depends on both physical and cognitive factors. Changes in the color and intensity of light alter the image received by the eye. The method of presenting the product to the sorters also has an important effect on perception. If product speed is too fast, it is not possible to fixate properly on a defect and hence, it is not possible to reach a decision about whether or not the item should be rejected.