1. College of Biosystems Engineering and Food Science; Zhejiang Univ.; Hangzhou 310058 China
2. Inst. of Quality and Standard of Agricultural Products; Zhejiang Academy of Agricultural Sciences; Hangzhou 310021 China
3. College of Animal Sciences; Zhejiang Univ.; Hangzhou 310058 China
4. Dept. of Biological & Agricultural Engineering; Univ. of Arkansas; Fayetteville Arkansas 72701 USA