This invention provides a fermented whey preparation produced by carrying out of high-temperature sterilization of an aqueous whey protein solution having a solid content of 11 to 35% by weight and a pH value adjusted to 6.5 to 8.0, then subjecting the sterilized aqueous whey protein solution to lactic acid fermentation, and homogenizing the resultant fermentation liquor. In this case, lactose contained in the sterilized aqueous whey protein solution after the high-temperature sterilization is enzymatically degraded with lactase at a stage before the lactic acid fermentation, during the lactic acid fermentation and/or after the lactic acid fermentation to enhance sweetness. The fermented whey preparation of the present invention has a good flavor provided by imparting unique sourness produced by fermentation and natural sweetness and, at the same time, has a refreshed and invigorating flavor and further has a velvety texture. Further, the fermented whey preparation has excellent thermal stability and safety.
