I've been experiencing an "off" taste to some milk since 2009. Not a sour taste per say, but more of a plastic, chemical kind of taste. It seems to go in cycles, being fine for a few months and then being "off" again for several jugs in a row. This month, I've had four jugs in a row that have been "off", and have wound up having to dump about 3/4 of each jug. The taste is tolerable at first, then increases in intensity such that within 24 to 48 hours it is undrinkable.
I live in the Greater Vancouver area, and I buy whole milk in four litre plastic jugs. I've bought milk from Lucerne (Safeway), Dairyland (Buy Low Foods), and Foremost (Superstore). The Dairyland milk has been consistently "off" since spring 2010, and I have stopped buying it. The "off" taste is consistent in the Foremost milk, but not as bad as the others. The problem is intermittent in the Lucerne milk, but is worse than the other milk when it is present.
Usually I buy the Lucerne milk, given that the problem is intermittent. The "off" taste is not tolerable in the Dairyland, and I buy the Foremost only occasionally because I don't like shopping at Superstore.
Cereal usually masks the "off" taste; and the "off" taste is tolerable in hot chocolate for about 24 to 48 hours after I buy the milk, and in cold chocolate milk for about 12 to 24 hours. It is not tolerable at all in a plain glass of cold milk.
I found the following discussion of this issue:
[url=http://tim.2wgroup.com/blog/archives/001974.html]Random Observations: Is Milk's Taste Changing?[/url]
Wondering if any other babblers have had a similar experience with "off" milk and/or if anyone has any suggestions on what to do or ideas as to what might be the cause of this "off" taste.