Off-flavors and odors can be present in raw milk due to practices on the farm. Some
are minor and difficult to avoid, while others are due to poor practices and can be reason for rejecting a milk load.
Most flavor/odor defects will be carried over into the finished product, although some of the volatile defects can be
partially removed. Defects in milk can be classified as Absorbed - odors breathed in by cows transmitted to the
milk through their blood stream (e.g., barny/cowy, feed) or odors directly absorbed by the milk during storage;
Bacterial - growth of spoilage microorganisms (e.g., malty/acid due to poor cooling); or Chemical - related to
enzymes and spontaneous chemical reactions (e.g., rancid due to excessive agitation; oxidized due to high fat
feeds), health of the cow (e.g., ketosis), and/or direct chemical contamination (e.g., cleaning chemicals, ointments).
For more information on milk flavors see the handout Sensory Evaluation of Milk & Dairy Products.