1. Division of Microbiology, National Institute of Health Sciences
2. Division of Microbiology, National Institute of Health Sciences, 1–18–1 Kamiyoga, Setagaya-ku, Tokyo 158–8501, Japan
3. Food Research Laboratories, Mitsui Norin Co., Ltd.
4. Food Research Laboratories, Mitsui Norin Co., Ltd., 223–1 Miyabara, Fujieda, Shizuoka 426–0133, Japan