Pickled beets do not have to be stored in canning jars, but they must be kept tightly sealed and refrigerated after opening. Once opened, beets maintain peak quality for approximately one to three months, after which time color, odor and texture may be altered.
Commercially-manufactured pickled beets are labeled with the manufacturer's estimate for the retention of peak quality. As long as the product is continuously refrigerated after opening, the beets are probably safe to consume after the labeled date. Signs that they are no longer safe to consume include an off odor, flavor or appearance, at which point they should be discarded. They are not safe to eat if mold is present in any quantity.