1. Microbiological and Analytical Group, Food Research Laboratories, Mitsui Norin Co. Ltd, 223-1, Miyahara, Fujieda, Shizuoka 426-0133, Japan
2. Central Research Laboratories, Tokyo Food Techno Co. Ltd, 223-1, Miyahara, Fujieda, Shizuoka 426-0133, Japan
3. Marine Biotechnology Institute, 3-75-1, Heita, Kamaishi, Iwate 026-0001, Japan
4. Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1, Yayoi 1-chome, Bunkyo-ku, Tokyo 113-0032, Japan