Reusing food presents special challenges. First, there is the fact that much food goes bad, or becomes unsuitable for human use before it ever reaches a pot or plate. The usual estimate is that 40% of all food is wasted or discarded, and much of this happens before food is taken home to eat. Expired labels or slight deterioration result in food being taken out of markets to be slated for disposal. Taking it out of packages can be too difficult to send it off for animal food. Much ends up in dumpsters (supersize garbage cans) where some people, known as “dumpster divers” may try to recapture it for consumption since it is basically in good condition. Supermarkets, for reasons known only to themselves, may make reuse difficult or impossible. For example, they may lock their dumpsters. Still, many people live for years on just the discarded food they get from dumpsters.
The second problem is that food is consumed in use. It is not available for simple reuse over and over. Still, there is an organic cycle, in which the atoms of the food (mostly carbon, oxygen, nitrogen, sulfur, some metals and minerals and of course hydrogen) are still available for some kind of reuse. They have been changed to excretions through metabolism (fecal matter and urine) and must not be reused willy nilly but must be carefully controlled in a hygienic society. For the most part they are washed away to a waste treatment plant which, if the thinking and arrangements are advanced, may allow the solid matter to be recirculated back to soil as a fertilizer. This application is made more difficult because there are two contaminants that enter the disposal water – heavy (or poisonous) metals and poisonous drugs. These render the reuse of wastewater treatment solids chancy and so the solids are often composted (despite the actual inability of composting to remove the contaminants) and then used on soil, or else thrown into an ocean or a local waterway. This situation is far from desirable.
There are also food scraps that are not eaten, which may mount up, especially as one includes peels, rinds, expired foods, cobs, leaves and more. In my house, not one scrap of any of this valuable organic matter is placed in a (garbage) can for discard. Every scrap is collected, cut and diced small, and placed on my garden to enrich the organic matter of the soil. It would be wonderful if this method could be universally taught and practiced. The scraps last from a day or two to a few weeks before they deteriorate to where they are unrecognizable.
The more common method in the USA is to place food scraps and prunings despite their value, in a garbage can to be collected by a garbage company for composting* or discard in a dump. The best fate would be personal composting, or just grinding and slurrying in water, using a blender, followed by application to the soil. I have long maintained that this organic matter should make the return trip to where plants are depleting soil and applied to renew the soil.
Now comes a new study reported in Archaelogy Magazine Sept-Oct 2020 that demonstrates an even better way to close the reuse cycle. They report on large, black soil areas of the Amazon Basin where research has established that organic matter was dumped in one place for many years, enriching the local soil and turning it black. After many years of this, the enriched soil could be used for agriculture and older, abandoned soil could then be similarly enriched. This illustrates the danger of relying too strongly on a simple, seemingly obvious method of reuse. Reuse is a complex subject, which needs study and design before one can arrive at a superior method. That is true of the reuse of all objects, not just food, but here we have a nice example for food. Read the article
*Composting is a great industrial operation but probably has no place in a backyard where the conditions it needs are hard to meet. Just use grinding or dicing and distribute scraps into any place where plants grow. They will love you for it and you will hear them sing happy songs in the evening.
There is an outfit called Feeding America with a different goal. They try to find a digital app way for anyone with surplus food to contact them to pick up the food and distribute it to the hungry. Here is their writeup.