Food waste or food loss is food that is discarded or lost uneaten. As of 2011, 1.3 billion tons of food, about one third of the global food production, are lost or wasted annually.[1] Loss and wastage occurs on all steps in the food supply chain. In low-income countries most loss occurs during production, while in developed countries much food – about 100 kilograms (220 lb) per person and year – is wasted at the consumption stage.[2]
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The definition of waste is a contended subject, often defined on a situational basis, and this also applies to food waste.[3] Professional bodies, including international organizations, state governments and secretariats may use their own definitions.[4]
Definitions of food waste vary, among other things, in what food waste consists of,[5] how it is produced,[6] and where or what it is discarded from or generated by.[5] Definitions also vary because certain groups do not consider (or have traditionally not considered) food waste to be a waste material, due to its applications.[7][8] Some definitions of what food waste consists of are based on other waste definitions (e.g. agricultural waste), and which materials do not meet their definitions.[9]
A 2011 study by the Swedish Institute for Food and Biotechnology (SIK) on behalf of Food and Agriculture Organization of the United Nations (FAO), Global Food Losses and Food Waste, distinguishes between "food loss" and "food waste", and provides figures for both:
In the European Union, food waste is defined as "any food substance, raw or cooked, which is discarded, or intended or required to be discarded" since 1975.[11][12][12] The directive, 75/442/EEC, containing this definition was amended in 1991 (91/156) with the addition of "categories of waste" (Annex I) and the omission of any reference to national law.[13]
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".[6] The states remain free to define food waste differently for their purposes,[7][14] though many choose not to.[9]
In developing and developed countries which operate either commercial or industrial agriculture, food waste can occur at most stages of the food industry and in significant amounts.[15] 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.[16][17] Nevertheless, on-farm losses in storage in developing countries, particularly in Africa, can be high although the exact nature of such losses is much debated.
Research into the food industry of the United States, whose food supply is the most diverse and abundant of any country in the world, found food waste occurring at the beginning of food production.[15] From planting, crops can be subjected to pest infestations and severe weather,[18][19] which cause losses before harvest.[15] Since natural forces (e.g. temperature and precipitation) remain the primary drivers of crop growth, losses from these can be experienced by all forms of outdoor agriculture.[20] The use of machinery in harvesting can cause waste, as harvesters may be unable to discern between ripe and immature crops, or collect only part of a crop.[15] Economic factors, such as regulations and standards for quality and appearance,[21] also cause food waste; farmers often harvest selectively, preferring to leave crops not to standard in the field (where they can be used as fertilizer or animal feed), since they would otherwise be discarded later.[15]
Food waste continues in the postharvest stage, but the amounts of postharvest loss involved are relatively unknown and difficult to estimate.[22] Regardless, the variety of factors that contribute to food waste, both biological/environmental and socio-economical, would limit the usefulness and reliability of general figures.[22][23] In storage, considerable quantitative losses can be attributed to pests and microorganisms.[24] This is a particular problem for countries that experience a combination of heat (around 30°C) and ambient humidity (between 70 and 90 percent), as such conditions encourage the reproduction of insect pests and microorganisms.[25] Losses in the nutritional value, caloric value and edibility of crops, by extremes of temperature, humidity or the action of microorganisms,[26] also account for food waste;[27][28] these "qualitative losses" are more difficult to assess than quantitative ones.[29] Further losses are generated in the handling of food and by shrinkage in weight or volume.[15][30]
Some of the food waste produced by processing can be difficult to reduce without affecting the quality of the finished product.[31] Food safety regulations are able to claim foods which contradict standards before they reach markets.[32] Although this can conflict with efforts to reuse food waste (such as in animal feed),[33] safety regulations are in place to ensure the health of the consumer; they are vitally important, especially in the processing of foodstuffs of animal origin (e.g. meat and dairy products), as contaminated products from these sources can lead to and are associated with microbiological and chemical hazards.[34][35]
Packaging protects food from damage during its transportation from farms and factories via warehouses to retailing, as well as preserving its freshness upon arrival.[36] Although it avoids considerable food waste,[36][37] packaging can compromise efforts to reduce food waste in other ways, such as by contaminating waste that could be used for animal feedstocks.[38]
Retail stores can throw away large quantities of food. Usually, this consists of items that have reached their sell-by or use-by dates. Most of this food is edible at the time of disposal, but stores have widely varying policies to handle the excess food. Some stores put effort into preventing access to poor or homeless people, while others work with charitable organizations to distribute food. Retailers also contribute to waste as a result of their contractual arrangements with suppliers. Failure to supply agreed quantities renders farmers or processors liable to have their contracts cancelled. As a consequence, they plan to produce more than actually required to meet the contract, to have a margin of error. Surplus production is often simply disposed. [39]
The 2011 SIK study estimated the total of global food loss and waste to around one third of the edible parts of food produced for human consumption, amounting to about 1.3 billion tons per year.[40] As the following table shows, industrialized and developing countries differ substantially. In the latter, more than 40% of losses occur at the postharvest and processing stages, while in the former, more than 40% of losses occur at the retail and consumer levels. The total food waste by consumers in industrialized countries (222 million tons) is almost equal to the entire food production in sub-Saharan Africa (230 million tons).[41]
| Food loss and waste per person and year[42] | Total | At the production and retail stages | By consumers |
|---|---|---|---|
| Europe | 280 kg (620 lb) | 190 kg (420 lb) | 90 kg (200 lb) |
| North America and Oceania | 295 kg (650 lb) | 185 kg (410 lb) | 110 kg (240 lb) |
| Industrialized Asia | 240 kg (530 lb) | 160 kg (350 lb) | 80 kg (180 lb) |
| Subsaharan Africa | 160 kg (350 lb) | 155 kg (340 lb) | 5 kg (11 lb) |
| North Africa, West and Central Asia | 215 kg (470 lb) | 180 kg (400 lb) | 35 kg (77 lb) |
| South and Southeast Asia | 125 kg (280 lb) | 110 kg (240 lb) | 15 kg (33 lb) |
| Latin America | 225 kg (500 lb) | 200 kg (440 lb) | 25 kg (55 lb) |
In the UK, 6.7 million tonnes per year of wasted food (purchased and edible food which is discarded) amounts to a cost of £10.2 billion each year. This represents costs of £250 to £400 a year per household.[43]
A study by the University of Arizona in 2004 indicated that 14-15 per cent of US edible food is untouched or unopened, amounting to $43 billion worth of discarded, but edible, food.[44] Another survey, by the Cornell University Food and Brand Lab, found that 93 percent of respondents acknowledged buying foods they never used.[45]
Response to the problem of food waste at all social levels has varied hugely.
One way of dealing with food waste is to reduce its creation. This attitude has been promoted by campaigns from advisory and environmental groups,[46] and by concentrated media attention on the subject.[43][47]
Psychology can be useful in helping reduce food waste. There are two ways we can reduce food waste, either prevent consumers from throwing away huge amounts of food as waste, or stop them in some way from producing so much. Once people begin a certain behavior in their lives, it is difficult to discourage it. So rather than discouraging them from wasting food, it is easier for someone to act as a good influence on them not to even begin wasting food in the first place. As children, it is easier to establish a social norm for them, but it is harder for them to change it later in their lives. We can establish a form of positive punishment to the child.[48] For example, if a children decide not to finish their food on their plates, then the parents can scold them so the children realize the parents are disappointed or angry with them. The children may be scared, so they will be less likely to throw food away. This way may work, or instead, negative punishment can also be useful, for example, not giving dessert to children if they do not finish all their food. Positive punishment has been more effective according to many studies.
If adults have established a negative behavior, it is extremely difficult for them to suddenly stop wasting too much food. Our parents are our main influence growing up, so getting rid of these prints can be difficult, but still possible. To begin with the idea of small steps at a time, asking people to think about what they want to eat gets them thinking about how to portion their food for themselves. This is a smaller step than asking them not to take as much food. Asking them about what barriers exist in their lives may also help; barriers are one of the main causes that stop people from changing their behaviors. Barriers associated with wasting food include not wanting to get up and refill one's plate, inconvenience, and not thinking holistically. Holism involves seeing the idea of wasting less food as a whole positive effect across the world and not only themselves. People tend to see the present, but forget about the effects in the future. Combining these ideas can work to help people throw away less food, which will certainly lead to a decrease in food waste piles.[49]
Consumers can reduce their food waste output at points-of-purchase and in their homes by adopting some simple measures; planning when shopping for food is important, and spontaneous purchases are shown as often the most wasteful. Proper knowledge of food storage reduces foods becoming inedible and thrown away.[46]
In areas where waste collection is a public function, food waste is usually managed by the same governmental organization as other waste collection. Most food waste is combined with general waste at the source. Separate collections, also known as source-separated organics, have the advantage that food wastes can be disposed of in ways not applicable to other wastes.
From the end of the 19th century through the middle of the 20th century, many municipalities collected food waste (called "garbage" as opposed to "trash") separately. This was typically disinfected by steaming and fed to pigs, either on private farms or in municipal piggeries.[50]
Separate kerbside collection of food waste is now being revived in some areas. To keep collection costs down and raise the rate of food waste segregation, some local authorities, especially in Europe, have introduced "alternate weekly collections" of biodegradable waste (including, e.g., garden waste), which enable a wider range of recyclable materials to be collected at reasonable cost, and improve their collection rates. However, they result in a two-week wait before the waste will be collected. The criticism is, though, particularly during hot weather, food waste rots and stinks, and attracts vermin.
Much kitchen waste also leaves the home through garbage disposal units.
Like other waste, food waste can be dumped, but it can also be fed to animals (typically swine), or it can be biodegraded by composting or anaerobic digestion, and reused to enrich soil.
Dumping food waste in a landfill causes odour as it decomposes, attracts flies and vermin, and has the potential to add biological oxygen demand (BOD) to the leachate. The EU Landfill Directive and Waste Regulations, like regulations in other countries, enjoin diverting organic wastes away from landfill disposal for these reasons. In countries such as the US and the UK, food scraps constitute around 19% of the waste dumped in landfills, where it ends up rotting and producing methane, a greenhouse gas.[45]
Food waste can be composted at home, avoiding central collection entirely, and many local authorities have schemes to provide subsidised composting bin systems. However, the proportion of the population willing to dispose of their food waste in that way may be limited.
Anaerobic digestion produces both useful gaseous products and a solid fibrous "compostable" material. Anaerobic digestion plants can provide energy from waste by burning the methane created from food and other organic wastes to generate electricity, defraying the plants' costs and reducing greenhouse gas emissions.
Food waste coming through the sanitary sewers from garbage disposal units is treated along with other sewage and contributes to sludge.
Commercially, food waste in the form of wastewater coming from commercial kitchens’ sinks, dishwashers and floor drains is collected in holding tanks called grease interceptors to minimize flow to the sewer system. This often foul-smelling waste contains both organic and inorganic waste (chemical cleaners, etc.) and may also contain hazardous hydrogen sulfide gases. It is referred to as fats, oils, and grease (FOG) waste or more commonly “brown grease” (versus “yellow grease”, which is fryer oil that is easily collected and processed into biodiesel) and is an overwhelming problem, especially in the USA, for the aging sewer systems. Per the US EPA, sanitary sewer overflows also occur due to the improper discharge of FOGs to the collection system.[51] Overflows discharge 3 billion US gallons (11,000,000 m3) - 10 billion US gallons (38,000,000 m3) of untreated wastewater annually into local waterways, and up to 3,700 illnesses annually are due to exposure to contamination from sanitary sewer overflows into recreational waters.[52]
In US metropolitan areas, the brown grease is taken by pumpers or grease-hauling trucks to wastewater treatment plants, where they are charged to dump it. In other areas, it may be taken to a landfill or it may be illegally dumped somewhere unknown, to avoid charges. This unmonitored disposal process is not only harmful for our environment and our health, but it also hurts businesses which have no idea where their business waste ends up, or indeed how much liquid waste is in their grease interceptors at any point in time, leaving them vulnerable to illegal dumping into their own grease traps or interceptors. Some companies now market computerized monitoring services along with in situ bioremediation, which produces byproducts of CO2 and gray water that can safely flow into sewer systems. Other new technologies offer ex situ treatment to process brown grease into some form of transportation fuel. This may not be as environmentally friendly as in situ treatment, since it still requires vehicles to pump and transport the brown grease waste to the plants.
Estimating how much brown grease food waste is produced annually is difficult, but in the US alone, number is thought to be in the billions of gallons. In 2009, the city of San Francisco stated it produces about 10 million US gallons (38,000 m3) of brown grease a year. It is starting the first city-wide project in the US to recycle brown grease into biodiesel and other fuels.[53]