1. Department of Nutrition and Food Hygiene, Yantai Center for Disease Control and Prevention, Yantai, China.
2. Office of General Administration (Department of Audit), Yantai Center for Disease Control and Prevention, Yantai, China.
3. Laboratory of Bacterial Testing, Yantai Center for Disease Control and Prevention, Yantai, China.
4. Department of Public Health Monitoring and Evaluation, Yantai Center for Disease Control and Prevention, Yantai, China.