When I drank milk, I would make kefir with milk from the store, it tasted awful. Then I started buying milk from this farmer in El Galpon in Chacarita. I think it's really fresh, the fat of the milk was on the top and it had a different color, sort of like raw milk in NY and it tasted good. But I am not sure anymore, plus so much has changed in this market since the owners have changed, they are not as ethical and are more about making money now. So be careful, ask around first, and not to anyone who is working in the market. I think Bomplant market is good, I went there today, and it looked they sold dairy products. The farmers market in Dorrego is a good place to ask, they might know someone, these people seem real nice, but they don't sell dairy products from what I saw, but they do know some good farmers and can probably send you to a decent one.
I agree, you should be careful in where you get your milk from, because they are not so clean here. I went to Quinta in a province in BA and they use to make jams and sold them at El Galpon, (this was two years ago) and the condition of the kitchen was gross. The flies in the compost (which was inside the house) were flying all over the kitchen and they also had stray cats inside the house. So know your farm or Quinta, I suggest visiting. If they have nothing to hide, they will let you visit, from my experience.
