The food use hierarchy

As you’ve seen, food waste results in the loss, not only of the food itself but of all the resources that went into creating it such as land, water, labour, energy, fuel, packaging, etc. And when food waste goes to landfill it releases greenhouse gases (GHGs) – mainly methane, which is 23 times more potent than carbon dioxide [1].

Many organisations involved in efforts to address food loss and waste (FLW) have developed ‘management hierarchies’ that rank various strategies for managing it. They are often referred to as ‘waste management’, ‘food recovery’, or ‘food use’ hierarchies, and are usually presented diagrammatically in the form of an inverted pyramid, such as the one below. These hierarchies provide useful guidelines for national and regional governments, food manufacturers, grocery retailers, growers and consumers in deciding how to prevent and manage food waste.

The food waste hierarchy focuses on delivering the best environmental option for dealing with waste. ‘Prevention’ is therefore at the top of the inverted pyramid as the best option and at the bottom the least good option is ‘disposal’. The principle of the framework is to keep food products at the highest tier possible, redefining waste as a potential resource rather than as an unwanted burden.

However, there is growing international consensus that a food use hierarchy is needed to shift the focus towards reusing food, first for human consumption and second as animal feed, keeping food in the food chain for as long as possible. The best option is, again, ‘prevention’ with a focus on reducing waste at source. This is followed by diverting surplus to human consumption or livestock feed. If that can’t be achieved, anaerobic digestion (to produce biogas) is preferable to composting in terms of recycling. And an incineration step for waste recovery is preferable to disposal.

Food Use Hierarchy (adapted from WRAP UK)

The seven tiers are grouped into three treatment categories:

• The green tiers which represent food not being wasted as waste is either prevented or the food reused.
• The yellow/orange tiers which represent the treatment of food waste either by recycling or by recovering energy from it.
• The final tier, the tip of the pyramid, which represents disposal.

The seven tiers can also be grouped into five categories of actions:

Prevention

Waste prevention at source – optimising planning to reduce surplus food and provide only what we need, and improving processing/operational efficiencies.

Reuse

Waste prevention through reuse – redistributing or finding alternative uses within the food or feed chain. Supermarkets and wholesalers may donate mislabelled or damaged packaged foods, overstocks, test-market products, and short-dated foods to people in need through food banks and other charities.

Food that’s not edible for humans should be used as animal feed when it’s safe to do so. It’s important to note however that leftovers or food scraps that contain or have come into contact with meat or meat products are banned from being reused as animal feed. Many viruses can survive for extended periods in meat and can cause severe diseases in livestock such as foot-and-mouth disease and swine fever. In recent years there’s been research and campaigns that support the claim that it’s safe to feed pigs and chickens with treated leftovers containing meat, however legislation remains unchanged.

Recycling

Reprocessing food waste into valued raw materials or new products. Biological treatment recycles the nutritive value back into material that can be used to grow new food. The two most common biological treatment methods for food waste are anaerobic digestion and composting.

• Anaerobic digestion is the process by which microorganisms break down organic material into biogas with a high methane content which can be used to generate heat and power. The left-over digestate is a nutrient-rich solid or liquid which can be used as a soil improver or fertiliser.
• Composting is the process by which microorganisms break down organic material aerobically to produce a soil conditioner rich in nutrients which can be used instead of synthetic fertilisers. Composting requires space and is easy to do in rural and suburban areas, but less easy in cities where the vast majority of organic waste ends up in landfill.

Recovery

Extracting energy by incinerating a mixed waste stream consisting of food waste and other municipal wastes (a mass-burn). This produces energy in the form of electricity, heat or both.

Disposal

Disposal of food waste without extracting any value is the lowest tier in the food use hierarchy. This includes waste incinerated without energy recovery, waste sent to landfill and waste products entering the sewerage system. Traditional landfill sites have caused serious public health issues in the past and have had detrimental environmental impacts including air pollution, methane emissions, and water pollution.

Towards a more sustainable food system

The food use hierarchy is a key set of principles to follow in developing a more sustainable food system. A future-proof food system will also address how to use fewer resources in the production of our food in the first place. And food that was previously seen as waste will be seen to have value and used as a resource to feed back into the food system. You’ll find out more about this concept, known as the circular economy, in the next Step.

How can we apply the hierarchy in our everyday life?

The first priority is to prevent waste. Food suitable for human consumption should be shared with people to make the best use of all the resources invested in that food.

• Shop wisely, store smartly and monitor expiry dates.
• Donate food to food banks, shelters, community fridges, family, or neighbours.

The next priority is to recycle:

• Some local authorities offer collecting food waste from households for recycling [2]. These schemes have a wide range of benefits including diverting biodegradable waste from landfill and reducing waste disposal costs. However, less than a half (48%) of all local authorities in England provide a food waste collection service. In contrast, Wales recycles more than 60% of its food waste thanks to a free food waste collection service provided by local authorities which covers 99% of all residents.
• Compost food at home or look in your local area for community groups running composting projects. Here’s a practical guide on how to deal with kitchen and garden waste through home composting.

Minimise the food you dispose of. When waste cannot be prevented, recycled or recovered, it goes to landfill. This has high costs and contributes to GHG emissions, soil depletion and pollution.

Following these simple steps to avoid food waste WILL make a difference and contribute to fighting climate change. Over the course, we’ll be providing tips and practical strategies to help you do this.

Would you be willing to apply these principles in your everyday life and inspire others to do so too?

References

1. Methane facts and information
2. Household food waste collections guide