'Indefinitely' is the actual word the United States Department of Agriculture uses as well, and they are typically understood to be very conservative.
Because freezing keeps food safe indefinitely, recommended storage times are for quality only, even though the quality of a food will not decrease significantly during storage as long as the food is stored properly.
Maintaining a food’s quality depends on several factors: the quality of the raw product, the procedures used processing, the way the food is stored, and the length of storage. The recommended storage time takes these factors into consideration. Storage times are from date of purchase unless specified on chart. It is not important if a date expires after food is frozen.