If you bought whole milk carrying the brand name "Castle Rock Organic Farms" and dated February 29th, you should throw it away.
The Castle Rock Organic Plant in Osseo says the product may not be properly pasteurized. Testing by the Wisconsin Department of Agriculture, Trade and Consumer Protection confirmed the possibility the pasteurization could be lacking. There have been no official reports of illness associated with the problem. The half-gallon and quart glass bottles would include a dairy plant number of 55-1951 on the side. The milk is believed to have been sold in this state, Minnesota and Illinois.