1. Tianjin Entry-Exit Inspection and Quarantine Bureau, Beijing, People's Republic of China.
2. Department of Microbiology, Chinese PLA General Hospital, Beijing, People's Republic of China.
3. Department of Microbiology, 3201 Hospital, Hanzhong, People's Republic of China.
4. National Institutes for Food and Drug Control, Beijing, People's Republic of China.
5. China National Center for Food Safety Risk Assessment, Beijing, People's Republic of China.