1. 1Department of Animal and Food Sciences, Texas Tech University, P.O. Box 42141, Lubbock, Texas 79409
2. 2Department of Food Science and Technology, Food Industry Complex, University of Nebraska–Lincoln, 124 VDC, East, Lincoln, Nebraska 68583-0907
3. 3Department of Veterinary and Biomedical Sciences, University of Nebraska–Lincoln, 124 VDC, East, Lincoln, Nebraska 68583-0907
4. 4Animal Diagnostic Laboratory, Pennsylvania State University, State College, University Park, Pennsylvania 16820, USA