Nobody wants to be wasteful. But in reality, most people are wasting a tremendous amount of perfectly good food every year. From stores throwing out food that's still edible, to consumers doing the same. It's an ironic fact of life that the most prosperous areas are often the quickest to forget how valuable food really is. Thankfully, it's never too late to make some positive changes and learn to use food to it's maximum potential. In particular, one can learn which foods are still good after their expiration date.
The first thing to keep in mind is that people often mean very different things when they're talking about expiration dates. An expiration date is usually assumed to mean the time after which food is considered to be inedible. Basically, when the food has expired. In reality though, when people talk about expiration dates they're really referring to an item's sell by date. The sell by date is the window in which an item can be sold in stores. A store will generally determine the sell by date in order to ensure a consistent taste, texture, and general appearance of foods.
This might seem like pointless semantics at first. But there's a very big difference between a sell by date, and an item no longer being edible. Items beyond the sell by date will often only have small visual differences from otherwise fresh items. There might be a small bruise on an item, or the peel might be different while the actual edible portion of the food remains exactly the same as it was while within the sell by window.
One of the more surprising items are vegetables. People often assume that vegetables will go bad fairly quickly when left at room temperature. Green leafy vegetables will often appear to go bad fairly quickly. But the only difference is that they're not quite as green as they used to be. Carrots experience something similar. Their coloration can fade over time while the actual taste is still as delicious as ever. The same goes for nutritional value. Even if the items don't look as fresh as they once did, the actual nutrients within them will almost always be preserved.
It's best to think of these foods as aged, rather than expired. Often times the only thing that's really changed about the vegetables is slight lack of water. Peas are a good example of this. They become harder and somewhat leathery over time. But when prepared as part of a juice or even a soup, they'll pick up moisture during preparation.
Though canned items are the most extreme example of food that can go to waste. Stores tend to be quite conservative when judging the shelf life of canned goods. It's difficult to know exactly how food will react to long term storage within a can. At least that's true as far as appearance goes. This is usually only cosmetic though. When an item is canned, it's placed in a perfectly sterile environment. There's no air for bacteria or other microorganisms to grow. This allows it to function in a similar way to a freezer. When food goes bad, it's usually because of the actions of microorganisms. Canned items, especially if they have extra preservatives, can last five, six, or even more years after their date of production. Meanwhile, stores often give them a sell by date of only a year or two.
Saving and making use of food that has passed the expiration date is a valuable practice on a number of different levels. It's a way of ensuring that one isn't wasting the earth's precious resources. And it also ensures that one isn't wasting money. It's a way of not only helping the environment, but also helping oneself as the same time.