Food loss and waste facts for kids

Fruit and vegetables in a dumpster, discarded uneaten

Food recovered by food waste critic Rob Greenfield in Madison, Wisconsin, from two days of recovery from dumpsters

Food loss and waste is food that is not eaten. The causes of food waste or loss are numerous and occur throughout the food system, during production, processing, distribution, retail and food service sales, and consumption. Overall, about one-third of the world's food is thrown away. A 2021 meta-analysis that did not include food lost during production, by the United Nations Environment Programme found that food waste was a challenge in all countries at all levels of economic development. The analysis estimated that global food waste was 931 million tonnes of food waste (about 121 kg per capita) across three sectors: 61 percent from households, 26 percent from food service and 13 percent from retail.

Food loss and waste is a major part of the impact of agriculture on climate change (it amounts to 3.3 billion tons of CO₂e emissions annually) and other environmental issues, such as land use, water use and loss of biodiversity. Prevention of food waste is the highest priority, and when prevention is not possible, the food waste hierarchy ranks the food waste treatment options from preferred to least preferred based on their negative environmental impacts. Reuse pathways of surplus food intended for human consumption, such as food donation, is the next best strategy after prevention, followed by animal feed, recycling of nutrients and energy followed by the least preferred option, landfill, which is a major source of the greenhouse gas methane. Other considerations include unreclaimed phosphorus in food waste leading to further phosphate mining. Moreover, reducing food waste in all parts of the food system is an important part of reducing the environmental impact of agriculture, by reducing the total amount of water, land, and other resources used.

The UN's Sustainable Development Goal Target 12.3 seeks to "halve global per capita food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses" by 2030. Climate change mitigation strategies prominently feature reducing food waste. In the 2022 United Nations Biodiversity Conference nations agree to reduce food waste by 50% by the year 2030.

Definition

A conceptual framework for food loss and waste (FLW)

Food loss and waste occurs at all stages of the food supply chain – production, processing, sales, and consumption. Definitions of what constitutes food loss versus food waste or what parts of foods (i.e., inedible parts) exit the food supply chain are considered lost or wasted vary. Terms are often defined on a situational basis (as is the case more generally with definitions of waste). Professional bodies, including international organizations, state governments, and secretariats may use their own definitions.

United Nations

The Food and Agriculture Organization (FAO) of the United Nations defines food loss and waste as the decrease in quantity or quality of food along the food supply chain. Within this framework, UN Agencies distinguish loss and waste at two different stages in the process:

• Food loss occurs along the food supply chain from harvest/slaughter/catch up to, but not including, the sales level
• Food waste occurs at the retail and consumption level.

Important components of this definition include:

• Food redirected to nonfood chains (including animal feed, compost, or recovery to bioenergy) is not counted as food loss or waste. Inedible parts are not considered as food loss or waste (these inedible parts are sometimes referred to as unavoidable food waste)

Under Sustainable Development Goal 12, the Food and Agriculture Organization is responsible for measuring food loss, while the UN Environmental Program measures food waste.

European Union

In the European Union (EU), food waste is defined by combining the definitions of food and waste, namely: "any substance or product, whether processed, partially processed or unprocessed, intended to be, or reasonably expected to be ingested by humans (...)" "which the holder discards or intends or is required to discard".

United States

Food waste alternative.

As of 2022, the United States Environmental Protection Agency (EPA) employed three categories:

• "Excess food refers to food that is recovered and donated to feed people."
• "Food waste refers to food such as plate waste (i.e., food that has been served but not eaten), spoiled food, or peels and rinds considered inedible that is sent to feed animals, to be composted or anaerobically digested, or to be landfilled or combusted with energy recovery."
• "Food loss refers to unused product from the agricultural sector, such as unharvested crops."

In 2006, the EPA defined food waste as "uneaten food and food preparation wastes from residences and commercial establishments such as grocery stores, restaurants, produce stands, institutional cafeterias and kitchens, and industrial sources like employee lunchrooms".

The states remain free to define food waste differently for their purposes, though as of 2009, many had not done so.

Other definitions

Bellemare et al. (2017) compared four definitions from:

1. a Food and Agriculture Organization (FAO) 2016 report: "Food loss is defined as ‘the decrease in quantity or quality of food.’ Food waste is part of food loss and refers to discarding or alternative (nonfood) use of food that is safe and nutritious for human consumption along the entire food supply chain, from primary production to end household consumer level";
2. an Economic Research Service (ERS; a USDA agency) 2014 report: "Food loss represents the amount of food postharvest, that is available for human consumption but is not consumed for any reason. It includes cooking loss and natural shrinkage (for example, moisture loss); loss from mould, pests, or inadequate climate control; and food waste. Food waste is a component of food loss and occurs when an edible item goes unconsumed, as in food discarded by retailers due to color or appearance, and plate waste by consumers";
3. a FUSIONS (an EU project) 2016 report: "Food waste is any food, and inedible parts of food, removed from the food supply chain to be recovered or disposed (including composed [sic], crops ploughed in/not harvested, anaerobic digestion, bioenergy production, co-generation, incineration, disposal to sewer, landfill or discarded to sea)"; and
4. an EPA 2016 report: "The amount of food going to landfills from residences, commercial establishments (e.g., grocery stores and restaurants), institutional sources (e.g., school cafeterias), and industrial sources (e.g., factory lunchrooms). Pre-consumer food generated during the manufacturing and packaging of food products is not included in EPA's food waste estimates."

According to Bellemare et al., the inclusion of food that goes to nonfood productive use is flawed for two reasons: "First, if recovered food is used as an input, such as animal feed, fertilizer, or biomass to produce output, then by definition it is not wasted. 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." They argued that only food that ends up in landfills should be counted as food waste, pointing to the 2016 EPA definition as a good example. Bellemare et al. also noted that "the FAO and ERS definitions only apply to edible and safe and nutritious food, whereas the definitions of FUSIONS and the EPA apply to both edible and inedible parts of food. Finally, the ERS and EPA definitions of food waste exclude the food that is not harvested at the farm level."

A 2019 FAO report stated:

'The notion of food being lost or wasted is deceptively simple, but in practice there is no commonly agreed definition of food loss and waste. FAO has worked towards the harmonization of concepts related to food loss and waste, and the definitions adopted in this report are the result of a consensus reached in consultation with experts in this field. This report understands food loss and waste as the decrease in quantity or quality of food along the food supply chain. Empirically it considers food losses as occurring along the food supply chain from harvest/slaughter/catch up to, but not including, the retail level. Food waste, on the other hand, occurs at the retail and consumption level. This definition also aligns with the distinction implicit in SDG Target 12.3. This report also asserts that, although there may be an economic loss, food diverted to other economic uses, such as animal feed, is not considered as quantitative food loss or waste. Similarly, inedible parts are not considered as food loss or waste.'

Methodology

The 2019 FAO report stated: "Food loss and waste has typically been measured in physical terms using tonnes as reporting units. This measurement fails to account for the economic value of different commodities and can risk attributing a higher weight to low-value products just because they are heavier. [This] report acknowledges this by adopting a measure that accounts for the economic value of produce." Hall et al. (2009) calculated food waste in the United States in terms of energy value "by comparing the US food supply data with the calculated food consumed by the US population." The result was that food waste among American consumers increased from "about 30% of the available food supply in 1974 to almost 40% in recent years" (the early 2000s), or about 900 kcal per person per day (1974) to about 1400 kcal per person per day (2003). A 2012 Natural Resources Defense Council report interpreted this to mean that Americans threw away up to 40% of food that was safe to eat. Buzby & Hyman (2012) estimated both the total weight (in kg and lbs) and monetary value (in USD) of food loss in the United States, concluding that 'the annual value of food loss is almost 10% of the average amount spent on food per consumer in 2008'.

Extent

Food loss from post-harvest to distribution in 2016, percentages globally and by region

Food waste infographic produced by Next Generation Food, 2010

Global extent

Efforts are underway by the Food and Agriculture Organization (FAO) and the United Nations Environment Programme (UNEP) to measure progress towards SDG Target 12.3 through two separate indices: the Food Loss Index (FLI) and the Food Waste Index (FWI).

According to FAO's The State of Food and Agriculture 2019, globally, in 2016, around 14 percent of the world's food is lost from production before reaching the retail level. Generally, levels of loss are higher for fruits and vegetables than for cereals and pulses. However, even for the latter, significant levels are found in sub-Saharan Africa and Eastern and South-Eastern Asia, while they are limited in Central and Southern Asia.

Estimates from UN Environment's Food Waste Index suggest that about 931 million tonnes of food, or 17 percent of total food available to consumers in 2019, went into the waste bins of households, retailers, restaurants and other food services.

According to a report from Feedback EU, the EU wastes 153 million tonnes of food each year, around double previous estimates.

Earlier estimates

In 2011, an FAO publication based on studies carried out by The Swedish Institute for Food and Biotechnology (SIK) found that the total of global amount of food loss and waste was around one third of the edible parts of food produced for human consumption, amounting to about 1.3 billion tonnes (1.28×10⁹ long tons; 1.43×10⁹ short tons) per year. As the following table shows, industrialized and developing countries differ substantially. In developing countries, it is estimated that 400–500 calories per day per person are wasted, while in developed countries 1,500 calories per day per person are wasted. In the former, more than 40% of losses occur at the post-harvest and processing stages, while in the latter, more than 40% of losses occur at the retail and consumer levels. The total food waste by consumers in industrialized countries (222 million tonnes or 218,000,000 long tons or 245,000,000 short tons) is almost equal to the entire food production in sub-Saharan Africa (230 million tonnes or 226,000,000 long tons or 254,000,000 short tons).

A 2013 report from the British Institution of Mechanical Engineers (IME) likewise estimated that 30–50% (or 1.2–2 billion tonnes or 1.18×10⁹–1.97×10⁹ long tons or 1.32×10⁹–2.20×10⁹ short tons ) of all food produced remains uneaten.

Individual countries

Australia

Each year in New South Wales, more than 25 million meals are delivered by charity OzHarvest from food that would otherwise be wasted. Each year, the Australian economy loses $20 billion in food waste. This has a crucial environmental impact through the waste of resources used to produce, manufacture, package, and distribute that food.

In addition, it is estimated that 7.6 million tonnes of CO₂ is generated by the disposed food in landfills. It is also the cause of odour, leaching, and potential generation for diseases. In March 2019, the Australian ministry of the environment shared the key findings of Australia's National food waste baseline, which will facilitate the tracking of the progress towards their goal to halve Australian food waste by 2030.

Many initiatives were taken by the Australian government in order to help achieve this goal. In fact, they financed $1.2 million in organization that invest in renewable energies systems to store and transport food. They also funded more than $10 million for research on food waste reduction. Local governments have also implemented programs such as information sessions on storing food and composting, diversion of waste from restaurants and cafes from landfills to shared recycling facilities and donation of food to organization that would otherwise be wasted.

Canada

In Canada, 58% of all food is wasted, amounting to 35.5 million tonnes of food per annuum. The value of this lost food is equivalent to CA$21 billion. Such quantities of food would be enough to feed all Canadians for five months. It is estimated that about one third of this waste could be spared and sent to those in need. There are many factors that contribute to such large-scale waste. Manufacturing and processing food alone incur costs of CA$21 billion, or 4.82 million tons. Per household, it is estimated that $1,766 is lost in food loss and waste. The Government of Canada identifies three main factors contributing to household waste: (1) buying too much food and not eating it before it spoils, (2) malfunctioning or poorly-designed packaging that does not deter spoilage rates or contamination, and (3) improper disposing of food – using garbage bins instead of those intended for organic waste.

Canada, Mexico, and the United States are working together under the Commission for Environmental Cooperation in order to address the severe problem of food waste in North America.

Canada specifically is working in the following ways to reduce food waste:

• Canada pledged to consult on strategies in the Strategy on Short-lived Climate Pollutants to reduce avoidable food waste within the country. This will help to reduce methane emissions from Canadian landfills.
• The government has implemented a Food Policy for Canada, which is a movement towards a more sustainable food system.
• In February 2019, the government brought together several experts from different sectors to share ideas and discuss opportunities for measuring and reducing food loss and waste across the food supply chain.

During the 2022 Quebec general election, Québec solidaire party spokesman Gabriel Nadeau-Dubois stated that ending food waste in Quebec would be a priority of the party if in government. The party seeks to cut food waste by 50% by mandating large businesses and institutions to give unsold food to groups that would distribute the food, or to businesses that would process the food.

China

In 2015 the Chinese Academy of Sciences reported that in big cities there was 17 to 18 million tons of food waste, enough to feed over 30 million people. About 25% of the waste was staple foods and about 18% meat.

In August 2020 the Chinese Communist Party general secretary Xi Jinping said the amount of food waste was shocking and distressing. A local authority campaign "Operation empty plate" (Chinese: 光盘行动) was started to reduce waste, including encouraging food outlets to limit orders to one fewer main dish than the number of customers.

As of December 2020, a draft law is under consideration to penalise food outlets if they encourage or mislead customers to order excessive meals causing obvious waste, first with a warning and then fines of up to 10,000 yuan. It would allow restaurants to charge customers who leave excessive leftovers. Broadcasters who promote overeating or food waste could also be fined up to 100,000 yuan.

Denmark

According to Ministry of Environment (Denmark), over 700,000 tonnes per year of food is wasted every year in Denmark in the entire food value chain from farm to fork. Due to the work of activist Selina Juul's Stop Wasting Food movement, Denmark has achieved a national reduction in food waste by 25% in 5 years (2010–2015).

France

Food waste

In France, approximately 1.3–1.9 million tonnes of food waste is produced every year, or between 20 and 30 kilograms per person per year. Out of the 10 million tonnes of food that is either lost or wasted in the country, 7.1 million tonnes of food wasted in the country, only 11% comes from supermarkets. Not only does this cost the French €16 billion per year, but also the negative impact on the environment is also shocking. In France, food waste emits 15.3 million tonnes of CO₂, which represents 3% of the country's total CO₂ emission. In response to this issue, in 2016, France became the first country in the world to pass a unanimous legislation that bans supermarkets from throwing away or destroying unsold food. Instead, supermarkets are expected to donate such food to charities and food banks. In addition to donating food, many businesses claim to prevent food waste by selling soon-to-be wasted products at discounted prices. The National Pact Against Food Waste in France has outlined eleven measures to achieve a food waste reduction by half by 2025.

Hungary

According to the research of National Food Chain Safety Office in 2019 based on the official EU methodological framework, an average Hungarian consumer generates 68 kg food waste annually. 49% of this amount would be avoidable. The research team (Wasteless project) replicated the study in 2019 involving 165 households. According to the data, food waste generated by the Hungarian households was estimated to be 65.5 kg per capita annually. Between the two periods, a 4% decrease was observed, despite significant economic expansion.

In 2021, The Fidesz government of Viktor Orbán passed a law dealing with food waste.

Italy

According to REDUCE project, which produced the first baseline dataset for Italy based on official EU methodological framework, food waste is 530 g per person per week at household stage (only edible fraction); food waste in school canteens corresponds to 586 g per pupil per week; retail food waste per capita, per year corresponds to 2.9 kg. See [1]

Netherlands

According to Meeusen & Hagelaar (2008), between 30% and 50% of all food produced was estimated to be lost or thrown away at that time in the Netherlands, while a 2010 Agriculture Ministry (LNV) report stated that the Dutch population wasted 'at least 9.5m tonnes of food per year, worth at least €4.4bn.' In 2019, three studies into food waste in households in the Netherlands commissioned by the LNV were conducted, showing that the average household waste per capita had been reduced from 48 kilograms of "solid food (including dairy products, fats, sauces and soups)" in 2010, to 41.2 kilograms in 2016, to 34.3 kilograms in 2019. The waste of liquid foods (excluding beer and wine, first measured in 2019) that ended up in the sewer through sinks or toilets was analysed to have decreased from 57.3 litres per capita in 2010 to 45.5 litres in 2019.

New Zealand

This section is transcluded from Food waste in New Zealand

Research done on household food waste in New Zealand found that larger households and households with more young people created more food waste. The average household in this case study put 40% of food waste into the rubbish.

Singapore

In Singapore, 788,600 tonnes (776,100 long tons; 869,300 short tons) of food was wasted in 2014. Of that, 101,400 tonnes (99,800 long tons; 111,800 short tons) were recycled. Since Singapore has limited agriculture ability, the country spent about S$14.8 billion (US$10.6 billion) on importing food in 2014. US$1.4 billion of it ends up being wasted, or 13 percent.

On January 1, 2020, Singapore implemented the Zero Waste Masterplan which aims to reduce Singapore's daily waste production by 30 percent. The project also aims to extend the lifespan of the Semaku Landfill, Singapore's only landfill, beyond 2025. As a direct result of the project, food waste dropped to 665,000 tonnes, showing a significant decrease from 2017's all-time high of 810,000 tonnes.

United Kingdom

This section is transcluded from Food waste in the United Kingdom

In the UK, 6,700,000 tonnes (6,590,000 long tons; 7,390,000 short tons) 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.

United States

Estimates of food waste in the United States range from 35 million tons to 103 million tons. In a study done by National Geographic in 2014, Elizabeth Royte indicated more than 30 percent of food in the United States, valued at $162 billion annually, is not eaten. The University of Arizona conducted a study in 2004 that indicated that 14% to 15% of United States edible food is untouched or unopened, amounting to $43 billion worth of discarded, but edible, food. In 2010, the United States Department of Agriculture came forth with estimations from the Economic Research Service that approximates food waste in the United States to be equivalent to 141 trillion calories.

USDA data from 2010 shows that 26% of fish, meat, and poultry were thrown away at the retail and consumer level. Since then, meat production has increased by more than 10%. Data scientist Harish Sethu says this means that billions of animals are raised and slaughtered only to end up in a landfill.

Impact on the environment

Food waste is responsible for 6% of global greenhouse gas emissions

Empirical evidence at the global level on the environmental footprints for major commodity groups suggests that, if the aim is to reduce land use, the primary focus should be on meat and animal products, which account for 60 percent of the land footprint associated with food loss and waste. If the aim is to target water scarcity, cereals and pulses make the largest contribution (more than 70 percent), followed by fruits and vegetables. In terms of greenhouse gas (GHG) emissions associated with food loss and waste, the biggest contribution is again from cereals and pulses (more than 60 percent), followed by roots, tubers and oil-bearing crops. However, the environmental footprint for different commodities also varies across regions and countries, due, among other things, to differences in crop yields and production techniques. According to the IPCC 6th Assessment Report, the reduction of food waste would be beneficial for improving availability of resources such as "water, land-use, energy consumption" and the overall reduction of greenhouse gas emissions into the atmosphere.

Prevention and valorisation

Limiting food wastage has seen the adoption of former World War I and World War II slogans by antiwaste groups such as WRAP.

In 2022 United Nations Biodiversity Conference nations adopted an agreement for preserving biodiversity, including a commitment to reduce food waste by 50% by the year 2030.

According to FAO's The State of Food and Agriculture 2019, the case for reducing food loss and waste includes gains that society can reap but which individual actors may not take into account, namely: (i) increased productivity and economic growth; (ii) improved food security and nutrition; and (iii) mitigation of environmental impacts of losing and wasting food, in particular terms of reducing greenhouse gas (GHG emissions as well as lowering pressure on land and water resources. The last two societal gains, in particular, are typically seen as externalities of reducing food loss and waste.

Response to the problem of food waste at all social levels has varied hugely, including campaigns from advisory and environmental groups, and concentrated media attention on the subject.

As suggested by the food waste hierarchy, prevention and reuse pathways for human consumption have the highest priority levels for food waste treatment. The general approach to food waste reduction comprise two main pathways: prevention and valorisation. Prevention of food waste infers all actions that reduce food production and ultimately prevent food from being produced in vain, such as food donations or re-processing into new food products. Valorisation on the other hand comprise actions that recover the materials, nutrients or energy in food waste, for instance by producing animal feed, fuel or energy.

Multiple studies have studied the environmental benefits of food waste prevention measures, including food donations, recovery of unharvested vegetables for re-use in food production, re-processing of surplus bread for beer production, and producing chutney or juice from leftovers. Food waste can also be used to produce multiple high-value products, such as a fish oil substitute for food or feed use via marine micro algae, without compromising the ability to produce energy via biogas. The general consensus currently suggest that reducing food waste by either prevention or valorisation, for human consumption, infers higher environmental benefits compared to the lower priority levels, such as energy production or disposal.

Multiple private enterprises have developed hardware and software solutions dealing mainly with the prevention of food waste within foodservice production facilities (contract catering, hotels & resorts, cruise ships, casinos etc.), by gathering quantitative and qualitative data about the specific food waste, helping chefs and managers reduce food waste by up to 70% by improving and optimising their workflows and menus.

Food rescue

Main page: food rescue

There are multiple initiatives that rescue food that would otherwise not be consumed by humans anymore. The food can come from supermarkets, restaurants or private households for example. Such initiatives are:

• food banks,
• online platforms like Too Good To Go and Olio,
• public foodsharing shelves like those from foodsharing.de and
• dumpster diving.

Consumer marketing

One way of dealing with food waste is to reduce its creation. Consumers can reduce spoilage by planning their food shopping, avoiding potentially wasteful spontaneous purchases, and storing foods properly (and also preventing a too large buildup of perishable stock). Widespread educational campaigns have been shown to be an effective way to reduce food waste.

A British campaign called "Love Food, Hate Waste" has raised awareness about preventative measures to address food waste for consumers. Through advertisements, information on food storage and preparation and in-store education, the UK observed a 21% decrease in avoidable household food waste over the course of 5 years.

Another potential solution is for "smart packaging" which would indicate when food is spoiled more precisely than expiration dates currently do, for example with temperature-sensitive ink, plastic that changes color when exposed to oxygen, or gels that change color with time.

An initiative in Curitiba, Brazil called Cambio Verde allows farmers to provide surplus produce (produce they would otherwise discard due to too low prices) to people that bring glass and metal to recycling facilities (to encourage further waste reduction). In Europe, the Food Surplus Entrepreneurs Network (FSE Network), coordinates a network of social businesses and nonprofit initiatives with the goal to spread best practices to increase the use of surplus food and reduction of food waste.

An overarching consensus exists on the substantial environmental benefits of food waste reduction. However, rebound effects may cause substitutive consumption as a result of economic savings made from food waste prevention, potentially offsetting more than half of the avoided emissions (depending on the type of food and price elasticities involved).

Collection

Bins of food waste in ReFood bins locked in a cage to prevent dumpster diving

In areas where the 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 waste can be disposed of in ways not applicable to other wastes. In the United States, companies find higher and better uses for large commercial generators of food and beverage waste.

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.

Separate curbside 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 that particularly during hot weather, food waste rots and stinks, and attracts vermin. Waste container design is therefore essential to making such operations feasible. Curbside collection of food waste is also done in the U.S., some ways by combining food scraps and yard waste together. Several states in the U.S. have introduced a yard waste ban, not accepting leaves, brush, trimmings, etc. in landfills. Collection of food scraps and yard waste combined is then recycled and composted for reuse.

Disposal

As alternatives to landfill, food waste can be composted to produce soil and fertilizer, fed to animals or insects, or used to produce energy or fuel. Some wasted fruit parts, can also be biorefined to extract useful substances for the industry (i.e. succinic acid from orange peels, lycopene from tomato peels).

Landfills and greenhouse gases

Main page: landfill gas

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 European Union Landfill Directive and Waste Regulations, like regulations in other countries, enjoin diverting organic wastes away from landfill disposal for these reasons. Starting in 2015, organic waste from New York City restaurants will be banned from landfills.

In countries such as the United States and the United Kingdom, food scraps constitute around 19% of the waste buried in landfills, where it biodegrades very easily and produces methane, a powerful greenhouse gas.

Methane, or CH₄, is the second most prevalent greenhouse gas that is released into the air, also produced by landfills in the U.S. Although methane spends less time in the atmosphere (12 years) than CO₂, it's more efficient at trapping radiation. It is 25 times greater to impact climate change than CO₂ in a 100-year period. Humans accounts over 60% of methane emissions globally.

Fodder and insect feed

Large quantities of fish, meat, dairy and grain are discarded at a global scale annually, when they can be used for things other than human consumption. The feeding of food scraps or slop to domesticated animals such as pigs or chickens is, historically, the most common way of dealing with household food waste. The animals turn roughly two thirds of their ingested food into gas or fecal waste, while the last third is digested and repurposed as meat or dairy products. There are also different ways of growing produce and feeding livestock that could ultimately reduce waste.

Bread and other cereal products discarded from the human food chain could be used to feed chickens. Chickens have traditionally been given mixtures of waste grains and milling by-products in a mixture called chicken scratch. As well, giving table scraps to backyard chickens is a large part of that movement's claim to sustainability, though not all backyard chicken growers recommend it. Ruminants and pigs have also been fed bakery waste for a long time.

Certain food waste (such as flesh) can also be used as feed in maggot farming. The maggots can then be fed to other animals. In China, some food waste is being processed by feeding it to cockroaches.

Composting

Main page: Compost

Inevitable waste: peels of potato, onion, lemon, tangerine, banana, kiwi, egg shell

Food waste can be biodegraded by composting, and reused to fertilize soil. Composting is the aerobic process completed by microorganisms in which the bacteria break down the food waste into simpler organic materials that can then be used in soil. By redistributing nutrients and high microbial populations, compost reduces water runoff and soil erosion by enhancing rainfall penetration, which has been shown to reduce the loss of sediment, nutrients, and pesticide losses to streams by 75–95%.

Composting food waste leads to a decrease in the quantity of greenhouse gases released into the atmosphere. In landfills, organic food waste decomposes anaerobically, producing methane gas that is emitted into the atmosphere. When this biodegradable waste is composted, it decomposes aerobically and does not produce methane, but instead produces organic compost that can then be utilized in agriculture. Recently, the city of New York has begun to require that restaurants and food-producing companies begin to compost their leftover food. Another instance of composting progress is a Wisconsin-based company called WasteCap, who is dedicated towards aiding local communities create composting plans.

Municipal Food Waste (MFW) can be composted to create this product of organic fertilizer, and many municipalities choose to do this citing environmental protection and economic efficiency as reasoning. Transporting and dumping waste in landfills requires both money and room in the landfills that have very limited available space. One municipality who chose to regulate MFW is San Francisco, who requires citizens to separate compost from trash on their own, instituting fines for non-compliance at $100 for individual homes and $500 for businesses. The city's economic reasoning for this controversial mandate is supported by their estimate that one business can save up to $30000 annually on garbage disposal costs with the implementation of the required composting.

Home composting

Composting is an economical and environmentally conscious step many homeowners could take to reduce their impact on landfill waste. Instead of food scraps and spoiled food taking up space in trashcans or stinking up the kitchen before the bag is full, it could be put outside and broken down by worms and added to garden beds.

Anaerobic digestion

Main page: anaerobic digestion

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. The United States Environmental Protection Agency states that the use of anaerobic composting allows for large amounts of food waste to avoid the landfills. Instead of producing these greenhouse gasses into the environment from being in a landfill, the gasses can alternatively be harnessed in these facilities for reuse.

Since this process of composting produces high volumes of biogas, there are potential safety issues such as explosion and poisoning. These interactions require proper maintenance and personal protective equipment is utilized. Certain U.S. states, such as Oregon, have implemented the requirement for permits on such facilities, based on the potential danger to the population and surrounding environment.

Food waste coming through the sanitary sewers from garbage disposal units is treated along with other sewage and contributes to sludge.

Commercial liquid food waste

See also: Vegetable oil recycling

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 US, 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. Overflows discharge 3–10 billion U.S. gallons (11–38 million cubic meters) 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.

See also

• Gleaning
• Anaerobic digestion
• Waste & Resources Action Programme
• List of waste types
• Post-harvest losses (grains)
• Post-harvest losses (vegetables)
• Source Separated Organics
• Waste management