What does the term "shelf life" mean?

The term shelf  life means different things to different people.  To those employed in the food industry, it refers to the span of time from when a product is processed to the time when it is no longer fresh enough to be sold and should be taken off the shelf.  However, to the average consumer, the shelf life of a product refers to the length of time from when it is brought home to the time when it is no longer safe or of good enough quality to consume. 
 
The term can be used for foods kept in a kitchen cabinet, in the fridge, or in the freezer.  (After all, refrigerators and freezers also have shelves.)
 
Source(s):
Susan Brewer, Ph.D.  University of Illinois, Department of Food Science and Human Nutrition