meat and dairy products), as contaminated products from these sources can lead to and are associated with microbiological and chemical hazards.In 2013 the non-profit Natural Resources Defense Council (NRDC) performed research that they state suggests that the leading cause of food waste in America is due to uncertainty over food expiration dates, such as confusion in deciphering best before, sell-by or use-by dates.In low-income countries, most loss occurs during production, while in developed countries much food – about 100 kilograms (220 lb) per person per year – is wasted at the consumption stage.In the European Union, food waste was defined as "any food substance, raw or cooked, which is discarded, or intended or required to be discarded" since 1975 until 2000 when the old directive was repealed by Directive 2008/98/EC, which has no specific definition of food waste.The United States Environmental Protection Agency defines food waste for the United States as "uneaten food and food preparation wastes from residences and commercial establishments such as grocery stores, restaurants, and produce stands, institutional cafeterias and kitchens, and industrial sources like employee lunchrooms".
As the following table shows, industrialized and developing countries differ substantially.
However, usually when culling occurs at the production, food processing, retail and consumption stages, it is to remove or dispose of produce with a strange or imperfect appearance rather than produce that is spoiled or unsafe to eat.
In urban areas, fruit and nut trees often go unharvested because people either don't realize that the fruit is edible or they fear that it is contaminated, despite research which shows that urban fruit is safe to consume.
However, there might be economic losses if the cost of recovered food is higher than the average cost of inputs in the alternative, nonfood use.
Second, the definition creates practical problems for measuring food waste because the measurement requires tracking food loss in every stage of the supply chain and its proportion that flows to nonfood uses." In subsistence agriculture, the amounts of food waste are unknown, but are likely to be insignificant by comparison, due to the limited stages at which waste can occur, and given that food is grown for projected need as opposed to a global marketplace demand.