1. Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, P.O. Box 19687, 1100 Robert E. Lee Boulevard, New Orleans, Louisiana 70179; V-Labs, Inc., 423 North Theard Street, Covington, Louisiana 70433; and Marketing Quality Handling Research, Agricultural Research Service, U.S. Department of Agriculture, North Carolina State University, P.O. Box 7624, Raleigh, North Carolina 27695-7624