Flavor is known to be a key attribute that determines the acceptability of milk. This presentation will cover a range of off-flavor development sources, from farm to processing, focusing on spontaneous oxidized flavor (SOF) milk as well as aseptically processed milk. Spontaneous oxidized flavor (SOF) milk has been a problem for the dairy industry for many years, causing significant economic losses. After collecting raw milk labeled as SOF milk from the Midwest, causative off-flavor compounds were identified as microbial taints (i.e., 2-methylisoborneol) and disproved the hypothesis that the off-flavor was of oxidative origin. Identifying the source of the off-flavor marker provided a basis to improve farming practices to produce higher quality milk. Additionally it demonstrated the likelihood off-flavors in milk of the misclassification as SOF milk, which would inhibit developing solutions. In the second part of this presentation, a more in-depth understanding of the off-flavors generated during aseptic thermal treatment and subsequent storage will be discussed. Milk undergoes aseptic processing to enhance product stability and shelf life but the high temperature short time treatment can also be detrimental to flavor quality. Key off-flavor markers in aseptic milk were identified and pathways of generation were defined providing information for the development of successful flavor improvement strategies. The application of common food phenolic compounds (i.e., in cocoa, tea, and soybeans) to suppress off-flavor development and improve consumer acceptability in UHT products will also be discussed.