ABSTRACT
Fruits and vegetables are an important part of a healthful, balanced diet. They provide us with essential vitamins, are a rich source of protein and fiber, and are also aesthetically pleasing to the eye and the olfactory sense. However, unlike most other food commodities, fruits and vegetables continue to be living organisms even after harvest. As a result of their biological nature, they are subject to physical, chemical, and microbiological deterioration from the time they are harvested until consumption. Physical deterioration includes bruising, softening, and moisture loss, the latter resulting in shriveling of products. Fruits and vegetables also continue to respire after harvest. These biochemical changes result in breakdown of carbohydrates and a buildup of CO
and C
H
,
changes in composition, and changes in the color and odor of many fruits and vegetables. In addition, enzymatic activity, e.g., pectinases, can result in softening of fruit. Microbiological deterioration due to the growth of molds, yeasts, and bacteria results in changes in the color, odor, and texture of products. All of these changes can occur alone or in conjunction with one another. For example, physical bruising will enhance the activity of polyphenoloxidase (PPO) enzymes and cause browning of tissue. Bruising will also facilitate the entry of spoilage microorganisms into the underlying tissues, thereby facilitating spoilage and the survival of human pathogens, should they be present (Wells and Butterfield, 1977, 1999). While good manufacturing practices and proper temperature or humidity control can reduce physical, chemical, and microbiological deterioration, proper packaging can also play an important role in maintaining the quality and shelf life of fresh produce throughout the distribution chain.
