These dates are not "use by" dates, but the time the container was actually filled.
: Retail Food Industry Center, University of Minnesota, ©1999.
In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or just no longer on a supermarket shelf (unfit for sale, but not yet unfit for use).
According to the USDA, "canned foods are safe indefinitely as long as they are not exposed to freezing temperatures, or temperatures above 90 °F (32.2° C)". In most food stores, waste is minimized by using stock rotation, which involves moving products with the earliest sell by date from the warehouse to the sales area, and then to the front of the shelf, so that most shoppers will pick them up first and thus they are likely to be sold before the end of their shelf life.
This is important, as consumers enjoy fresher goods, and furthermore some stores can be fined for selling out of date products; most if not all would have to mark such products down as wasted, resulting in a financial loss.
Presently the lack of uniformity among manufacturers has made the practice of open dating confusing and misleading.
Szybist Published 2001 Hardback 239 Pages Price: 103.00 [pounds sterling] (USA: Food & Nutrition Press) Open dating plays a vital role in the distribution of food products.Online version: Labuza, Theodore Peter, 1940-Current practices and regulations regarding open dating of food products. : Retail Food Industry Center, University of Minnesota, ©1999(OCo LC)930369498Current practices and regulations regarding open dating of food products/Theodore Peter Labuza; Lynn M Szybist; University of Minnesota. Appendices: Proposed 1999 TTI Legislation in Italy; Canadian Open-dating Legislation F&D; NIST Handbook 130--Uniform Open Dating Regulation as Adopted by The National Conference on Weights and Measures; Extended List of State Regulations on Open Dating; European Union; 1999 Legislative Proposal; Proposed Federal Open-Dating Regulation; Alabama Safe Foods Act of 2000. In spite of the fact that increasing numbers of food processing companies are moving to open dating it is not yet universal.Finally, federal open dating regulations across state borders would lessen burdens on interstate commerce.