• Quality assurance of study products: All products used in this study were manufactured and provided by Bright Dairy & Food Co., Ltd. The quality test of study products was conducted by Shanghai dairy products quality supervision and inspection station. The study products were stored at the study site and assigned to the subjects by the investigator. The amount of products received and assigned were filed on product distribution list by the investigator. The study products were not allowed to be given to anyone who didn't participated in the study. No sales of unassigned products was allowed. After the completion of the study, the unassigned products need to be returned to Bright Dairy & Food Co., Ltd.