1. Department of Veterinary Medical Science, University of Tokyo, Tokyo, Japan.
2. Department of Global Health Policy, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
3. Department of Health Policy, National Centre for Child Health and Development, Tokyo, Japan.
4. National Institute of Health Sciences, Tokyo, Japan.
5. Faculty of Economics, Kyushu University, Fukuoka, Japan.
6. Research Centre for Food Safety, University of Tokyo, Tokyo, Japan.