- Cribbed from New Scientist

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Food waste isn't just morally objectionable; it also produces vast amounts of greenhouse gases. But this is one food fight we can win, with simple actions at home and new tech in industry

By Marta Zaraska

I OFTEN feel guilty in the kitchen. The problem isn’t my cooking; I live in France and pride myself on my culinary skills. The cause of my guilt is the amount of food I keep throwing away. A pile of leftover pasta, the uneaten salmon from my daughter’s plate, some expired tofu discovered at the back of the fridge – in it all goes. It sits there in a heap on top of the plastic packaging in which most of the food came wrapped.

It might be a modest heap in my kitchen bin, but, worldwide, food waste is a problem of supersized proportions. About a third of all produce is lost or wasted, most of it thrown into landfill. As that food rots, it produces vast amounts of greenhouse gases. If food waste were a country, its carbon footprint would almost match that of the US. You might say that instead of cooking our food, we are cooking the planet. No wonder that scientists, campaigners – and plenty of ordinary folk like me – are deeply worried.

I decided to turn to science and ask what we really know about how to make sure less food is squandered. It was eye-opening, to say the least. I have changed the way I shop and eat. My preferences on the way food is packaged have been transformed. I also learned that the food industry is at the beginning of some sweeping technological shifts, which could see food waste become not a problem, but an opportunity.

For most of human history, sustenance has been hard won and not something we would have dreamed of wasting. I grew up in communist Poland. I remember the food shortages people experienced back then and how my mother cried when mice once got into our stock of sugar. Millions of people still live in food poverty. But those in richer parts of the world now have the dubious luxury of being able to waste food.

It is hard to tell exactly how much ends up rotting because most of it isn’t tracked. Our best estimate comes from a 2011 report by the UN Food and Agriculture Organization (FAO), which suggested that about 1.3 billion tonnes of food worldwide is lost or wasted each year. That is a third of all produce and recent analysis suggests that, if anything, this is an underestimate.

There are some things I already do to reduce this problem, like composting vegetable peelings. But those actions have limits. To go deeper, I call Erica van Herpen at Wageningen University in the Netherlands, who studies consumer behaviour. One question that has been bothering her for years is why people waste food when nearly all of us say we don’t wish to. “You don’t want to have food waste, but it’s like collateral damage, it happens along the way,” she says.

To get at the causes, van Herpen and her colleagues have been collecting fine-grained data on what people buy and throw away, asking them to complete surveys and food diaries and to snap photos of their food refuse. Other groups have gone even further in the name of science. In 2019, Michael von Massow and his colleagues at the University of Guelph, Canada, dug through the bins of 94 families in Ontario to discover what food a typical household throws away. This kind of work has begun to provide us with better answers about what drives household food waste.

Van Herpen’s work showed that some of the main culprits are shopping without a list and buying things you don’t need. A lack of cooking skills is also a big one – burning food, for instance, so you have to toss it out. Another is preparing too much, like I did with my daughter’s salmon. This means there are simple things we can all do to help.

Other studies have begun to reveal the important and surprising role that packaging can play in averting food waste. These days, many of us are focused on using less plastic. Here in France, there is no shortage of markets where I can pick up meat and vegetables that come with minimal wrapping – perhaps just a little paper – and that seems like a win.

But avoiding plastic wrap entirely can backfire and lead to food going off more quickly, says Helén Williams at Karlstad University in Sweden. In unpublished work, Williams and her colleagues have conducted life-cycle analyses of various food products to compare the climate change impacts of the food itself versus its wrapping. They found that when it comes to lettuce, for instance, buying smaller bags of 30 grams of leaves instead of 65 grams resulted in people throwing out far less. The smaller bags had about 20 per cent more plastic per gram of lettuce, but a lower carbon footprint overall when food waste was accounted for.

Cereal killer

I have experimented with buying cornflakes from a zero-plastic store and transferring them to a jar at home. Unprotected by a vacuum seal, they quickly went stale and I threw them all away. A little waste plastic, it seems, is sometimes a lesser evil than a lot of wasted food.

This is especially true when it comes to foods that take a lot of resources to produce, like meat, eggs and cheese. “Those are very important to protect because otherwise the resources you have put in are lost,” says Williams. Of course, if you want to really lower your food-related carbon footprint, you can consider going vegan.

Now we have a better sense of what causes us to throw out food, we are beginning to scale up solutions. These include campaigns such as Love Food Hate Waste, run in the UK by the charity WRAP (Waste and Resources Action Programme). This initiative focuses on raising awareness of food waste and telling people how to reduce their contribution.

We are starting to see that this sort of approach can make a difference. A 2019 review of 17 food waste information campaigns conducted by Christian Reynolds at the University of Sheffield, UK, and his team found that, in some cases, food waste was reduced by up to 28 per cent. Van Herpen says they could be more effective still if people are also given proper tools. Even simple things can help, such as recipe books for leftovers or measurement cups that tell you how much rice or pasta to cook for a certain number of people. A fridge thermometer can be handy too. While many people in the UK keep their fridges at about 7°C, the optimal temperature to prevent food going off is below 5°C.

I am beginning to feel like my kitchen will soon be less wasteful. But one place my good intentions are scuppered is when I eat out – and that’s bad news. “Food consumption out of the home is extremely wasteful,” says Viachaslau Filimonau, who studies hospitality management at Bournemouth University, UK. A recent report produced for the UK’s House of Lords showed that hospitality and catering industries in the country were responsible for 1.1 million tonnes of food waste in 2018 out of a total of 9.5 million tonnes. It is a similar proportion on average across the European Union. In restaurants the food is mostly wasted in the kitchen, while in fast food joints it is mostly wasted by consumers.

The good news is that Filimonau’s research has shown that up to 79 per cent of that waste is avoidable and the solutions aren’t complicated. The Guardians of Grub, another campaign by WRAP, shares success stories. For instance, when The Ship Inn, a pub in Cumbria, UK, started offering fewer chips with dishes and putting out smaller portions of sauce, food waste was quickly cut by 67 per cent – and customers were just as happy.

All this made me think I ought to eat out less often or at least choose a place that pays attention to waste. But it also got me wondering how consequential my efforts to cut waste at home really are. How does the amount of food waste produced in homes compare against that produced higher up the supply chain?

A major research project called Fusions, coordinated by Toine Timmermans at Wageningen University, found that 53 per cent of food waste across Europe came from households, with the rest generated from a mix of other stages of the supply chain. The picture in low-income nations is less clear. But the 2011 FAO report suggests that in less well-off nations more food is lost during production and less in homes compared with richer countries (see chart).

“Offering fewer chips with dishes and putting out less sauce cut food waste in the pub by 67 per cent – customers were just as happy”

Fighting food waste, then, means action both in households and further up the supply chain. That includes rethinking how we buy and sell food. When I once asked my 8-year-old to pick carrots in a store, she chose the most weirdly shaped ones “because they are so pretty”. But stores don’t tend to stock much misshapen produce because of the perception that consumers, at least adult ones, don’t like it. Several campaigns are now working to change this. The Portuguese cooperative Fruta Feia, or “Ugly Fruit”, buys produce too gnarly for supermarkets and sells it to customers attracted to its lower price and to the cooperative’s waste-prevention mission. A similar campaign by the French Intermarché and Auchan stores proved successful too. In one supermarket near Paris, 2 tonnes of ugly fruit was sold in 15 days.

Researchers tend to agree that prevention is our best line of defence. But there will inevitably be times when we just can’t eat what we have bought. The first alternative is called recovery, which applies to food that is still edible. The idea is simple: redistribute it to where it is needed. Food-sharing services do just this and they are becoming more popular. In the UK, a charity called FareShare redistributes surplus food from suppliers such as farms or supermarkets and delivers it to more than 10,500 charities and community groups. On OLIO, a leftover-sharing app, close to 3 million registered users in dozens of countries upload photos of their unwanted food, mark their location and hand over the goods to those who request them. A study by Tamar Makov at Ben-Gurion University of the Negev in Israel and her colleagues showed that OLIO saved 91 tonnes of food worth more than £700,000 over 18 months. “The sharing economy may offer powerful means for improving resource efficiency and reducing food waste,” the researchers wrote.

When food is no longer fit for the table, it can still be recycled. The first step is to collect it. At the moment, that’s only beginning to happen. A 2020 report commissioned by the Bio-based Industries Consortium estimated that 13 per cent of household food waste is collected in the UK, slightly behind the EU average of 16 per cent. Food waste collected by local authorities in the UK is either composted or put into an anaerobic digester, where microbes break it down into biofertiliser and gases like methane that are burned to produce electricity. While this still generates carbon emissions, it is carbon that has only recently been removed from the atmosphere by growing crops, making it a relatively benign source of energy. If all the food waste from UK households was to undergo anaerobic digestion, it could save the equivalent of 490,000 tonnes of carbon dioxide per year.

We could wring even more value from spoiled food by recycling it using what is known as a biorefinery. The idea is to use biological processes to not just break down food into a sludgy mess, but to produce valuable chemicals that can then be used as feedstocks to make other things.

Like oil, food is mainly composed of carbon-based molecules, so in theory it can be refined in the same way, although the job is more complex. Biorefineries are mostly at the prototype stage, but a few years ago, the Italian oil and gas company ENI converted one of its refineries to process waste cooking oils and fats instead of crude oil.

The development of biorefineries could be sped up though. Chemical engineer Dionisios Vlachos at the University of Delaware reckons the key is to find ways of converting the waste into higher value chemicals that could be used as feedstocks for a range of industries. For instance, potato peelings can be converted into HMF, a versatile biochemical that can be used to make textiles, cosmetics and packaging materials. Overall, Vlachos has found that a tonne of potato peelings could be transformed into a range of chemicals worth more than $6000 in total. Federico Battista at the University of Verona in Italy and his colleagues looked at coffee grounds and demonstrated how these could be converted into several valuable chemicals, including biodegradable polyesters that can be made into shoes, backpacks, ropes or even those tiny beads you can find in certain body scrubs.

Having biorefineries produce more profitable chemicals could prove a beneficial way of dealing with food waste in future. But for this to really take off, a few other things are needed, like better collections of waste in bulk and maybe the introduction of carbon taxes, to make the technique more competitive.

Meanwhile, there are encouraging signs that food waste may already be edging downwards in some places. In 2018, consumers in the UK wasted 6.6 million tonnes of food, which was a whopping 18 per cent less than in 2007. In terms of avoided emissions, that is like taking 2.1 million petrol cars off the road. Some of the savings were almost certainly due to higher food prices, but better consumer awareness probably helped.

Then there is the pandemic. One silver lining is that it seems to have made us waste less food. Stuck at home and unable to eat out even if I wanted to, I certainly found I was more careful with the contents of my cupboards. I did a lot of bulk buying, but managed my hauls deliberately, and cooked with leftovers. Surveys have shown that it isn’t just me: people in Spain, the Netherlands and the UK all seem to have wasted less food during lockdowns. Let’s just hope it’s a habit that sticks.

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