How long does unopened sour cream remain good?

In the supermarket, you may see products stamped with a date that’s 6 weeks or more into the future. (Experts say sour cream is good for about 45-60 days after manufacture.) “Best by” tells you the last date  that the manufacturer guarantees a product is at peak quality (assuming it’s been stored consistently at 40° F or lower). If your product has a “sell by” date, check the manufacturer’s website or phone customer service to find out how long after that date the product will still be good. Some companies guarantee their unopened sour cream for 1-2 weeks after the “sell-by” date.
 
Source(s):
FMI Deli Product Storage Chart
Dr. Robert Bradley, professor emeritus of food science, University of Wisconsin
Cary Frye, vice-president of regulatory affairs, International Dairy Foods Association