With its naturally tangy smell and tendency to separate, sour cream can be difficult to gauge when you're trying to figure out if it's still good. Of course, if it's got furry, black and green splotches on top, there's no question—throw it out. But if it hasn't reached this moldy stage yet, look for other more subtle signs.

When to Toss Sour Cream

A light layer of white, milky liquid floating on top of sour cream and a tangy odor are both totally normal. Simply stir it and it should be all good. However, if the whey seems curdled and the odor has gone from tangy to sour, discard the whole container.

If the sour cream has been in the refrigerator for a while, it may look and smell fresh to you but still harbor unsafe bacteria. According to Clemson University Cooperative Extension Service, sour cream stays fresh for up to two weeks; but the U.S. Department of Agriculture places the time period between seven and 14 days. Use your judgment after seven days, and definitely discard the product after it's been open for two weeks.

If a sour cream dip sits out at a party for more than two hours, bacteria have had a chance to multiply, and you need to throw the dip away.

The FoodSafety.gov website recommends throwing away a container of sour cream if your power goes out for longer than four hours, whether or not you've opened the container.

Tip

Most containers of sour cream should have a "sell-by," "use-by" or "best-by" date stamped on it; this means that a store has until that date to sell the product. Only buy a container that has not yet passed the date stamped.

About the Author

Susan Lundman

Susan Lundman began writing about her love of cooking, ingredient choices, menu planning and healthy eating after working for 20 years on children's issues at a nonprofit organization. She has written about food online professionally for ten years on numerous websites, and has provided family and friends with homemade recipes and stories about culinary adventures. Lundman received her M.A. from Stanford University.