Sour cream is produced by introducing a probiotic bacterial culture into cream. The culture produces lactic acid, which sours and thickens the cream.
Ranging from 18 to 20 percent fat, sour cream often contains additional ingredients such as gelatin, rennin and enzymes.
Light sour cream is made from half-and-half and contains about 40 percent less fat than regular sour cream; nonfat sour cream is thickened with stabilizers.
Selecting and Storing Sour Cream
Refrigerate sour cream for up to a week after the date stamped on the bottom of the container. If mold forms on the cream`s surface, discard it immediately.