Sour cream may be safe to eat after the expiration date passes, but is ideally discarded after the expiration date since that date indicates the last date food or beverages are safe to consume. The expiration date on foods falls into the broader category of food labeling. The expiration date indicates the maximum date foods stay fresh; eating foods past expiration dates may pose health and safety risks, including dairy products like sour cream and milk.
In addition to the expiration date, other standards used to indicate food safety include posting sell-by dates, dates of food manufacture, use by and guaranteed fresh dates. Some dates, such as guaranteed fresh, indicate foods may lose quality and freshness after the posted date, but may still be safe to eat.