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Roles of refrigeration on fresh produce chain |
S. E. PRUSSIA, Biological & Agricultural Engineering Dept., Univ. of Georgia, 1109 Experiment St., Griffin, GA 30223-1797 Refrigeration is absolutely essential for each business link in the many fresh produce chains that grow, distribute, and market fresh fruits and vegetables to distant homes, restaurants, and institutions. Early cooling after harvest, constant storage temperatures, and rapid delivery are necessary to satisfy consumer expectations for eating enjoyment, nutritional value, and low risk of food borne illness. Consumption quality is reduced by the cumulative effect of exposure time at each storage temperature. Losses double for a ten degree Celsius increase in temperature. The ideal temperature depends on the product, maturity at harvest, transit time, and for climacteric fruits, the desired ripeness at arrival. Uniform temperature inside cooled space depends on complete precooling, stacking patterns, sufficient air distribution, and adequate insulation. Constant temperatures prevent condensation, reducing decay. Proper temperatures are especially critical for the safety of fresh cut fruits and vegetables. Moisture loss from fresh produce during cold storage can be limited by maintaining high relative humidity (90 to 95 %). The amount of moisture lost by a product depends upon the vapor pressure deficit (VPD), which is calculated from the temperature and relative humidity. If relative humidity is increased, container designs must accommodate the resulting reduced strength of fiberboard containers. Gases such as ethylene and carbon dioxide must be considered when managing refrigerated spaces for fresh produce. Sufficient ethylene is produced by apples, tomatoes, bananas, and other climacteric fruits to cause damage to sensitive products like lettuce, cucumber, and snap beans. Tables are available showing groups of compatible products (for temperature, moisture, and gases). Economic studies are needed to show the feasibility of additional refrigerated spaces at wholesale, retail, and especially for home storage. Also needed is a systems approach for ensuring changes at one business link are compatible with other links.
Handout (.pdf format, 1157.2 kb)
Session 23, Impact of cold-chain management on fresh produce quality and safety
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