The U.S. National Resources Defense Council has studied our habits in throwing out food, concludes that we waste up to 40% of all food produced in the country; or, to put it another way, that food waste costs the average family $2275 a year; or yet another way, that 25% of the stuff in landfills is discarded food. Phenomenal! And shameful.
The study points out that waste occurs for many reasons: Consumers won't select blemished fruits/vegetables when purchasing; groceries overstock and have to discard food "past its date," restaurants oversize portions so more people leave food on the plate. Another trend I've noticed is toward temporary packaging: many things are getting put into pouches or pop-top cans. These are lighter and cheaper to produce but they're also clearly more fragile and less lasting. Tuna in a can can sit on your shelf for ten years if you want; I wouldn't trust tuna in a pouch for even one-tenth of that time.
The study also points to confusing and/or inconsistent dating on food packages as a cause. I hadn't thought of that, but I'm sure they're correct that with some dates labeled "sell by," others labeled "best by," and still others "use by," people throw out a lot of food that's really quite edible.
There are a lot of pitfalls in defining shelf life. We of an older generation, I think, are more likely to take a commonsense approach to what's usable. We didn't have dated packaging. The younger folks I suspect take this whole "dating game" more seriously. At the same time, our overlawyered society errs on the side of extreme caution in setting those dates. And I can imagine the immense waste that results from occurrences like the late June east coast power outage, when practically every supermarket was required to throw out all its frozen food.
People have to decide for themselves how to deal with the problem. I've never just looked at a date on a package or carton and just tossed it out; I want to look at the contents; my response to a date that's passed is usually to finish the item up sooner rather than later, but if it doesn't look bad, smell bad, or hasn't completely disintegrated (lettuce can deteriorate quickly), it doesn't get wasted. We're pretty good about buying what we need and using leftovers, and the last dabs get added to a container in the freezer that will eventually become an excellent soup that's different every time.
Overall, it seems we could do a lot better, as has been demonstrated in Europe.