The present invention provides a method for preventing the formation of abnormal flavor in raw milk or pasteurized milk and to provide pasteurized milk for use in the production of milk having good quality and flavor. During the course from the milking to the pasteurization in the milk processing process, a treatment for reducing the dissolved oxygen concentration is performed. The treatment is carried out within 72 hours after milking. After the treatment is completed, the dissolved oxygen concentration is maintained at a low level until the pasteurization is started. The prevention of the formation of abnormal flavor means the prevention of one or more of the spontaneous generation of oxidized odor in raw milk, the formation of and/or increase in a hexanal, the generation of heated odor, and the formation of and/or increase in a sulfide.
