Because sour cream is acidic, it will keep for weeks or maybe a month or two. Mold may grown on the top of it, but scoop it off, and use it. Especially if you are cooking with it, I would expect it would last for months refrigerated (use only very clean utensils to scoop it out so as not to contaminate it.

If you have sour cream, I believe that the identical bacteria are used to make buttermilk. Just as a test, I would blend a talespoon (15 mL) of sour cream into a cup (250 mL) of fresh milk, cover, andlet sit at room temperature overnight. It hould become sour and thick. I make buttermilk using buttermilk as a starter: 1 paret buttermilk plus four parts fresh milk. Mix and leave at room temperature overnight. Refrigerate, will keep for weeks. Info by David Fankhauser

-- Marie (prettyhollow@yahoo.com), February 19, 2002