1. Department of Nutrition and Food Science, University of Maryland, College Park, Maryland.
2. Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland.
3. Agricultural Research Service, Beltsville Agriculture Research Center, United States Department of Agriculture, Animal Parasitic Diseases Laboratory, Beltsville, Maryland.
4. National Academy of Sciences, Washington, DC.
5. Centers for Disease Control and Prevention, Atlanta, Georgia.