1. Division of Biochemistry, National Institute of Health Sciences, Kawasaki-ku, Kawasaki, Japan
2. Department of Food Hygiene, Hokkaido Institute of Public Health, Kita-ku, Sapporo, Japan
3. Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Japan
4. Food Hygiene Analysis Center, Nippon Kaiji Kentei Kyokai, Kanazawa-ku, Yokohama, Japan