Food waste in the food chain

Jodie Humphries

Food waste, it happens at every stage in the food chain - in fact, we're all guilty of it. As Next Generation Food has previously reported, estimates state that food wasted by Europe and the US could feed the world three times over. While an estimated 8.3 million tonnes of household food waste is produced each year in the UK, most of which could have been eaten.

Reducing food waste is a major issue and not just about good food going to waste; wasting food costs the average family with children GBP£680 a year and has serious environmental implications too.

The vast majority of us already think throwing away good food is a dreadful waste, but there are serious environmental implications too. The amount of food we throw away is a waste of resources. Just think about all the energy, water and packaging used in food production, transportation and storage. This all goes to waste when we throw away perfectly good food. If we all stop wasting food that could have been eaten, the CO2 impact would be the equivalent of taking one in four cars off the road.

As we said, food waste happens in every part of the food cycle. In developing and developed countries, who operate either commercial or industrial agriculture, food waste can occur at most stages of the food industry.

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. 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. From planting, crops can be subjected to pest infestations and severe weather, which cause losses before harvest. Since natural forces remain the primary drivers of crop growth, losses from these can be experienced by all forms of outdoor agriculture. 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. Economic factors, such as regulations and standards for quality and appearance, 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.

Food waste in processing

Food waste also happens in the post-harvest stage, but the amounts of post-harvest loss involved are relatively unknown and difficult to estimate.

In storage, considerable quantitative losses can be attributed to pests and microorganisms. 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. Losses in the nutritional value, caloric value and edibility of crops, by extremes of temperature, humidity or the action of microorganisms, also account for food waste; these "qualitative losses" are more difficult to assess than quantitative ones. Further losses are generated in the handling of food and by shrinkage in weight or volume.

Some of the food waste produced by processing can be difficult to reduce without affecting the quality of the finished product.

Food waste in Retail

Packaging protects food from damage during its transportation from farms and factories via warehouses to retailing, as well as preserving its freshness upon arrival. Although it avoids considerable food waste, packaging can compromise efforts to reduce food waste in other ways, such as by contaminating waste that could be used for animal feed-stocks.

Food waste in the home

The main reasons for throwing away food can be grouped in to "cooking or preparing too much" (for example cooking too much rice or pasta and it gets left in the saucepan or on the plate) or "not using food in time" - for example having to throw out fruit and vegetables because they've gone off in the fruit bowl or in the fridge, or not eating food before it goes past its use-by date.

The single largest producer of food waste in the United Kingdom is the domestic household. In 2007, households created 6,700,000 tonnes of food waste - accounting for 19 percent of all municipal solid waste. Potatoes account for the largest quantity of avoidable food disposed of; 359,000 tonnes per year are thrown away, 49 percent (177,400 tonnes) of which are untouched. Bread slices account for the second food type most disposed of (328,000 tonnes per year), and apples the third (190,000 tonnes per year). Salad is disposed of in the greatest proportion - 45 percent of all salad purchased by weight will be thrown away uneaten.

Much of the food thrown away could have been avoided (4,100,000 tonnes, 61 percent of the total amount of food waste) and with better management could have been eaten or used. Unavoidable foods, such as vegetable peelings and teabags, account for 19 percent of the total, with the remaining 20 percent being unavoidable through preferences (e.g. bread crusts) and cooking types (e.g. potato skins)

Food labelling

Food labels are there to give us information so that we can choose between foods, but sometimes they can be confusing.

There are rules that food manufacturers must follow that protect us from false claims or misleading descriptions, and there are clear guidelines on what labels can and can't show.

Use-by

This is the key date in terms of safety - never eat products after this date and observe storage instructions. Check if the food can be frozen if you need to eat it at a later date. 'Use by' dates are usually found on chilled products such as cooked meats, soft cheeses and dairy-based desserts.

Best before

'Best before' dates are usually on longer shelf life foods such as frozen, tinned or dried goods and refer to quality rather than safety. So, with these things, it's best to use your judgement. It should be safe to eat food after the 'best before' date, but food may no longer be at its best.

One exception is eggs - never eat eggs after the best before date.

Display Until \ Sell by

Date marks such as 'display until' or 'sell by' often appear near or next to the 'best before' or 'use by' date. They are used by some shops to help with stock control and are instructions for shop staff, not shoppers.

Is food waste collections and composting the answer?

Avoiding throwing out food that could have been eaten will save you money and help reduce greenhouse gas emissions. However, some food waste is inevitable. Egg shells, banana skins and tea bags are never going to be on the menu.

Home composting is a great way to stop this sort of waste ending up in landfill. If you live in an area that has local kerbside food collection service, you can use this to collect anything you can't eat, or home compost. It is recycled it into a good quality soil, improver or fertilizer.

In Scotland, they're taking action against food waste. Every home in Scotland is to have a special bin for discarded food after the Scottish Government announced a zero-waste strategy.

The collection of food waste is due to begin in 2015 under Government plans to have 70 percent of all waste recycled by 2025. It has also set a target to have no more than five percent of waste sent for landfill by that year, but a target or date for zero waste has not been set.

More than two million tonnes of food is thrown away in Scotland every year and the Government claims half of this could be used to power a city like Dundee for six months.

The average household throws out GBP£430 worth of food every year and the Government claims enough waste is produced every 10 minutes in Scotland to fill an Olympic-size swimming pool.

Environment Secretary Richard Lochhead said the measures would support the goal of reducing Scotland's greenhouse gas emissions by 42 percent by 2020 and 80 percent by 2050.

One way of dealing with food waste is to reduce its creation. This attitude has been promoted by campaigns from advisory and environmental groups, and by concentrated media attention on the subject.

Consumers can reduce their food waste output at point-of-purchase and in their home by adopting some simple measures; planning when shopping for food is important, spontaneous purchases are shown as often the most wasteful; proper knowledge of food storage reduces foods becoming inedible and thrown away.

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The impact of domestic food waste on climate change |Imperial College works to reduce food waste |Mounting food waste in supply chain |London highlights food waste