Blueberry taste is a defect appearing at irregular intervals in individual dairy herds' bulk tank milk, especially in northern Sweden. If there is a complaint, the producer receives an immediate price reduction and risks being cut off from delivery as long as the problem persists. The cause of "blueberry" taste has not yet been determined. The problem is most common during winter months. In recent years, SLU has received two smaller national grants to work on the problem, part of a LivsID grant (SLF) and one from Family Kamprad's Foundation (research programs attached). In those projects, we have recently identified an analysis technique that can link the taste defect to chemical changes in milk and feed, which is a breakthrough. To be able to explain why the changes in the milk occur on the farms, we now need to collect more milk and feed samples and animal data over a longer period of time. The results will form the basis of an advisory and action package to help affected producers.