TABLE OF CONTENTS About 69% of the table eggs produced in the United States are sold as shell eggs. The remainder are further processed into liquid, frozen, or dehydrated egg products that are used in food service or as an ingredient in food products. Small amounts of further processed eggs are converted to retail egg products, mainly mayonnaise, salad dressings, and egg substitutes. Shell egg processing includes cleaning, washing, drying, candling for interior and exterior defects, sizing, and packaging. Further processed eggs require shell removal, filtering, blending, pasteurization, and possibly freezing or dehydration.
After processing, shell eggs intended for use within several weeks are stored at 39 to 45 F and relative humidities of 75 to 80%. These conditions reduce the evaporation of water from the egg, which would reduce the egg's weight and hasten breakdown of the albumen (an indicator of quality and grade). Shell eggs are also refrigerated during transportation, during short- and long-term storage, in retail outlets, and at the institutional and consumer levels.
Research has shown that microbial growth can be curtailed by holding eggs at less than 41 F. USDA regulations require eggs to be kept in an ambient temperature below 45 F until they reach the consumer, to prevent the growth of Salmonella (see October 27, 1992, United States Federal Register). Storage and display areas must be refrigerated and able to maintain ambient temperatures at 45 F.
The parts of an egg are shown in Figure 1, and physical properties of...
