1. School of Biological and Food Engineering, Guangdong University of Petrochemical Technology, 525000 Maoming, Guangdong, P. R. China
2. Key Laboratory of Dairy Science, Ministry of Education, Northeast Agricultural University, 150030 Harbin, P. R. China
3. Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong University of Petrochemical Technology, 525000 Maoming, P. R. China