We can’t keep wasting food. Here’s what we can do about it.
How we eat is vital to the health of the planet. But by 2050, scientists predict the Earth’s population will be 9.6 billion.
So how do we feed the world sustainably? Our food production system is under increasing stress. Food already accounts for between a quarter and a third of global greenhouse gas emissions. Half of the world’s habitable land and 70% of global freshwater withdrawals are already used for agriculture, just to feed the population as it is now.
We also lose much of our crops to disease or less than perfect management, and pressures on production, like environmental change, pests, pathogens and soil degradation, are only set to increase.
And yet estimates say that right now, more than a third of the food we produce is lost or wasted. In the UK alone there are estimated to be over 15 million tonnes of food waste a year.
So while food waste will never be reduced to zero — and reducing food waste isn’t a one stop solution to the world’s future food deficit — it is a vital component in delivering global food security. And research has already come up with lots of ways to tackle the problem.
The staggering scale of food waste
A UN report estimates we waste:
- 20% of all meat and dairy produced
- 30% of all cereals
- 35% of all fish
- 40–50% of all fruit and vegetables
In the UK almost half of all food waste comes from households, while a third of all fruit and veg is discarded simply because they don’t meet cosmetic standards for supermarkets. (Although not all that produce goes wasted: much is used elsewhere.)
That waste amounts to £12.5 billion of food every year, but it’s not just an economic cost; food waste directly contributes to to increased conflict for fresh water and drives climate change.
Thankfully, there are ways we can tackle the problem of food waste, through innovations that reduce the amount of waste in the food chain, and others that make better use of the waste we can’t eliminate.
Keeping our food fresh for longer
Apples
Apples grown in the UK are stored for between four and 12 months in large controlled atmosphere stores. The key to keeping them fresh is to slow down how fast the apples use oxygen, preventing the fruit from ripening and going soft.
Controlled atmosphere stores keep oxygen levels and temperatures low. The lower the oxygen, the longer the apples will keep — but too little oxygen can cause the fruit to ferment, creating skin damage, browning and an off-flavour. Finding the right level is crucial to keeping the apples fresh.
Researchers from the University of Greenwich’s Natural Resources Institute have come up with a system, called SafePod, which can track how close apples are to fermenting, so the oxygen levels in each store can be adjusted.
The pod is filled with apples, and placed into the store. It detects if the apples become stressed and require more oxygen, so that storage conditions can be adjusted to prevent spoilage. It can also predict when the fruit is reaching the end of its storage life, and should be transported to shops.
The hope is that SafePod can not only reduce waste but help reduce the amount of apples we import, by making UK grown fruit available all year round.
Salad leaves
More than 40% of bagged salad leaves end up in the bin. Professor Gail Taylor and her colleagues from the University of Southampton worked with Vitacress, to understand how to keep salad leaves fresher for longer.
The team wanted to know why some salad leaves have a longer shelf life than others. Their research showed that smaller, tougher leaves, with lots of small cells packed closely together, lasted longer, and were easy to process.
The researchers then worked out which regions of the lettuce genome were responsible for these desirable characteristics — and now have initiated a programme in which crop breeders are selectively breeding plants to have a longer shelf life.
The researchers also made the unexpected discovery that using less water when growing salad can improve its shelf life.
Potatoes
More than 116,000 tonnes of potatoes are thrown away in the UK each year, in part because we don’t eat them before they turn green. But potatoes are vulnerable to climate change — very hot summers followed by very wet autumns means smaller harvests, so keeping our spuds fresh for longer is a key challenge. Researchers at the University of Southampton and the James Hutton Institute have been working with businesses like Waitrose and Sainsbury’s on packaging that blocks the light wavelengths that trigger potato greening, giving them an extra day’s shelf life.
Packaging could tell you when your produce will go off
Future research might even see us using packaging that can alert us to food nearing the end of its life, so that we can eat it before it goes off.
A project at Imperial College is investigating labelling that can tell you when your food was about to expire, by detecting the gases created by microbial activity.
The labelling technology exists, but researchers are now looking to see how consumers might use such labels and what impact it could have on how they treat food waste.
How food waste can help us get to Net Zero
Reducing food waste before it happens isn’t the only way to tackle the problem. Researchers all over the world are looking at ways to use the waste generated in the food chain to generate electricity or replace products that we currently make from raw materials.
Coffee
You might have heard the term ‘fully-washed’ when buying the fancier kind of coffee bean — but have you ever thought about what that means?
Millions of litres of water are needed to make the 160 million kilo-bags of coffee produced each year. That means large amounts of polluting liquid wastes, which can cause problems for countries that don’t have the infrastructure to process it.
Dr Claudio Avignone-Rossa from the University of Surrey has a solution that not only cleans the water but also produces electricity while doing so.
The waste water is run through a special kind of fuel cell, containing microbes that break down the organic matter in the waste and use it to generate electrical power.
At scale the system could clean waste water, allowing it to be reused and so relieving pressure on water supplies. The electricity supply it produces could also drive vital social and economic development for coffee farming communities.
Barley
Breweries across Europe throw out around 3.4 million tons of unspent grain every year, the equivalent of 500,000 elephants. So what if there was a way we could use that grain as biofuel?
Dr Ahmed Osman from Queen’s University Belfast has developed a technique to convert left over barley from breweries into carbon, which could be used as a renewable fuel for homes in winter, charcoal for summer barbecues or parts for water filters — and replacing carbon products usually shipped to the UK from overseas.
Palm Oil
Palm oil’s impact on tropical rainforests makes it a controversial ingredient — but did you know the oil extracted makes up as little as ten percent of the total biomass produced? As much as 90 per cent is classified as waste.
In Indonesia, palm oil is a vital ingredient in the food industry. The Indonesian government has also pledged to switch all filling stations from diesel to a biofuel blend, which is often made using palm oil.
So a method that can create that fuel from palm oil waste would help meet government targets without impacting the food industry or further contributing to the environmental impact of palm oil production.
Researchers at the Indonesian Institute of Sciences are hoping to develop a method of converting palm oil biomass waste into fuel using volcanic bentonite clay, a renewable and abundant resource in Indonesia.
Kitchen scraps
Researchers at Cranfield University are working with the University of York on making materials for clothing using crop and household waste, such as food scraps and kitchen roll.
The technique uses bacteria to produce cellulose from waste, and low impact solvents to dissolve it into a honey-like solution which can be spun into fibres.
Cellulose is naturally found in plants and wood but isn’t easy to extract without the use of toxic chemicals — currently used to make viscose and rayon for clothes.
The manufacturing process developed at Cranfield uses less aggressive solvents which will have a significantly lower environmental impact.
Lessons from lockdown
Our individual behaviour also has a part to play. Research shows there were significant changes in behaviour and a reduction in the self-reported level of food waste in the first national lockdown for Covid-19.
A study at the University of Leeds is now looking at the determinants of that behaviour — what impact emotions have on our behaviour around food waste, and what personal goals and values are tied to buying and eating.
Want to know more?
If you’re a UK taxpayer, your contributions help fund the work of researchers investigating questions like these, via UK Research and Innovation — the funding body that allocates government funds for research — and the nine research councils. The projects in this article are funded by the Biotechnology and Biological Sciences Research Council, the Engineering and Physical Sciences Research Council, and the Economic and Social Research Council. You can read more about what we do here.
You can read more on circular economies here, and more on making things from waste here.
The UN Food Systems Summit took place last week: find more here and 2021 is also the International Year of Fruit and Vegetables.
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