• Tips from Cornersmith: What not to throw away

Here's a nifty way to create more space in the fridge: next time you're unpacking the groceries, dunk one-fifth of the food straight in the bin. One in five bananas, every fifth slice of ham and 20 per cent of your sourdough loaf. Statistics show it's going to end up in the rubbish regardless, so you might as well get it out of the way early.

You see, Australians love food. We bloody adore it. But, according to FoodWise, a national campaign run by not-for-profit group DoSomething that aims to reduce the environmental impact of Australia's food consumption, we're also very good at wasting it. Aussie households bin $8 billion of worth of food a year, equal to one in five bags of groceries.

Why all the waste, pals? Are we a nation of overconsumers who don't know how to turn old bananas into delicious cake?

No, we're not, says Bethaney Turner, who focuses on sustainable food systems at Canberra University where she is assistant professor in international studies. The reasons for our food wastage are complex.

"There's a lot of noise made about people not having the skills to reuse leftover food, but we've found, and other research has found, that's actually not true," she says. "Lots of people know how to reuse food but they make different decisions in the home. People with families might not want their kids eating the same thing three days in a row, say. They want to expose their children to different types of food.

"People are also really concerned about their health. For example, I made a curry on the weekend and I planned to cook the leftovers in a different way the next day. But then I thought, 'Well, what happens when I have leftovers from my leftovers? Is it safe to reheat them?' The discourses around health and food safety have a key impact on the way people reduce – or not – food waste in the home."

Turner says another thing people often point out during her research, is that it's hard to purchase small quantities of foods such as bunches of spinach.

"It's often more expensive to do so too – look at the price of half a cauliflower versus a full one – and the smaller quantities often come with heaps of plastic wrapping which many people want to avoid. There's a constant juggling of values and how the hell we can make a 'good' choice.

"There's a place, absolutely, for education around cooking skills, but it's not the only answer."

The food waste problem goes well beyond households throwing out too much bread and lettuce. (Bread, by the way, is the food we bin the most.) Globally, 1.3 billion tonnes of food intended for human consumption is wasted a year when you take into account supply chains, production harvesting, restaurant waste and produce that doesn't meet the cosmetic standards to make it on the supermarket shelf. (Just on those "ugly" fruit and veg campaigns from major food outlets where misshapen or blemished produce is sold at cut-price: Turner believes they won't really help reduce food waste. Supermarkets can sell food cheap, but households will waste it anyway.)

Solving the global food waste problem is not a matter of digging more holes to be filled with old lettuce. When organic matter in landfill breaks down, it releases methane gas and landfill leachate that pollutes waterways. The United Nations says that if food waste were a country, it would be the third-highest global greenhouse gas emitter behind the US and China.

The war on food waste needs to be fought hard and fast on all fronts by every country.

Here's a few of our other favourite people and projects throwing heavy punches at food waste in Australia and around the world right now:

Ronni Kahn, social entrepreneur

It was only a matter of time, really, before Ronni Kahn effected change on the world stage. The social activist and entrepreneur is the driving force behind OzHarvest – a force for good which has, to date, rescued 21,000 tonnes of food to make 64 million meals to feed vulnerable Australians.

Now Kahn and the team have launched the world's first free supermarket, giving away rescued food. And it's open to everybody.

"In my head I've always wanted to do it. We were offered this space in late November/December and we were ready to go at the end of April. [As a company] we're nimble and agile and we like to make things happen," says Kahn. "We've got surplus food and the notion around OzHarvest has always been to give it away for free. That's our model."

The supermarket is a business model Kahn hopes to expand across the country, but big businesses will need to get behind it to make it viable – everything from the walls down to the food on the shelves has been donated. Property developers TOGA Group bought the Kensington building the supermarket resides in, donating the downstairs space to OzHarvest for the next year.

"To me, it's a beautiful alignment with what's happening in the commercial world," says Kahn. "We're never going to replace a major food business or supermarket chains. What we are offering people is the chance to take part in a different shopping experience and feel like they're part of the circular economy."

And while Kahn believes this is an opportunity for other business developers to get involved at ground level and do some good in the community, it's not necessarily her core driving force. "For me, there is surplus. We've got $20 billion worth of food going to waste in Australia, $10 billion of that is household, $10 billion is commercial. What it does is raises awareness, providing good, and providing good on both sides of the equation.

"Any thinking human understands that if a third of all food globally is going to waste there is something fundamentally wrong with the system."

OzHarvest supermarket 147 Anzac Parade, Kensington. Mon-Fri 10am-2pm.

Local councils and green bins

A growing number of local councils across Australia are investing in composting solutions that hinge on household food waste being collected separately to non-organic garbage. Lake Macquarie City Council in NSW, for instance, will introduce a three-bin service in 2018 after a successful trial in November.

Lake Macquarie residents will place all food waste into their kerbside green waste bin along with the garden waste currently accepted. The green waste will be processed into compost, mulch and soil conditioners for use on local parks, sporting grounds, school yards and community gardens.

Households will be issued with a kitchen food scraps container and a supply of compostable liners to separate food from other garbage. It's excellent that the scraps are going back into the earth, yes, but research also shows that the bodily process of separating food waste from the rest of the garbage can make a person more aware of what they're throwing out and stop food hitting the bin altogether.

lakemac.com.au

The Food Assembly

France is pretty into at this anti-food-waste business. Not only did it become the first country in the world to ban supermarkets from binning unsold food in 2016 (the food now goes to charities and food banks instead), there's also ripper initiatives such as The Food Assembly. Also known as La Ruche qui dit Oui! ("the hive says yes"), the independent project launched in 2011 now has more than 900 "assemblies" across Europe including 90 in Britain.

It's a beautifully simple concept: assembly members place their order online for fruit, veg, meat, cheese, fish, coffee, bread and even beer, then pop into the local collection point a couple of days later to collect their haul. The Food Assembly connects local farmers and food makers to the community while flipping a finger to the supermarkets and minimising food waste as producers only prepare or harvest to order. Brilliant.

thefoodassembly.com/en

Katy Barfield and Yume

Imagine putting five killer whales on a set of scales. That is the amount of surplus Rangers Valley beef Katy Barfield is dealing with, off the back of cancelled orders. When you read about food sharing apps, you think about half a leftover lasagne, or an errant leg of lamb. Not 30 tonnes of primo grade meat, or eight tonnes of ocean trout. But this is the other side of food waste – the commercial side that we rarely talk about, because it doesn't affect us on a day to day basis.

Barfield is the woman behind Yume – a wholesale website helping to reduce food waste from the top down. She works as a conduit between 500-700 companies, from chefs and cafes to convention centres. In turn, they use her online marketplace to buy discounted dishes and ingredients from 200-300 suppliers, ranging from mass to boutique.

Her advice when it comes to effecting change at grassroots? "Embrace the curly, embrace the wonky. Stop judging with your eyes. Smell your food."

yumefood.com.au

Tristram Stuart and Toast Pale Ale

"We hope to put ourselves out of business," says Tristram Stuart, British-based author, food waste fighter and founder of Toast Ale, a beer made using surplus fresh bread. "The day there's no wasted bread is the day Toast Ale can no longer exist."

Given that 44 per cent of all bread produced in Britain is thrown away, and British citizens bloody love a pint, it's a noble and logical pursuit. Stuart's team gathers leftover bread from delis and bakeries and mashes the loaves into breadcrumbs which are then brewed with malted barley, hops and yeast to make beer. Too easy.

The Toast team say they have also received a number of enquiries from Australian breweries keen to partner. Give us this day our daily bread beer.

toastale.com

Youth Food Movement and The Cookluck Club

The Youth Food Movement is a volunteer-led organisation empowering young people to do "cool stuff around food that makes a difference", says the group's national communications manager, Zo Zhou. Previous projects include Passata Day – a massive cookup to make the most of summer's tomatoes – and a series of "Spoonfed" workshops that encouraged people to look at food waste in creative new ways. Off the back of those workshops came the Cookluck Club, which invites mates to get together and cook tasty meals with food in need of rescuing.

"At one of the workshops, we gave the attendees a box of random ingredients on their last legs and told them to cook something," says Zhou. "They had so much fun and the dishes were really delicious. It was a moment of realisation for a lot of the attendees that they could create a beautiful meal with food that probably would have ended up in the bin."

Because not everyone is comfortable cooking on the fly, Youth Food Movement has developed a bunch of resources with chefs such as Stephanie Alexander to give members inspiration to cook with whatever's on the turn. Punters are invited to sign up to Cookluck Club online to access all the tips and material.

youthfoodmovement.org.au/cookluckclub​

Seven things you can do right now

• Only purchase food you are going to use, and don't fall for buy-two-get-one-free promotions if the bonus item will likely end up in the bin.
• Use your freezer to store excess food before it goes off.
• Write/email/ring your local politician demanding s/he #BanTheBag - 150 million plastic bags in Australia end up as litter every year.
• Keep reusable grocery bags in the boot of the car so they are on hand every time you are at the shops.
• Try to get as much reuse out of an item as possible – from plastic bags to jam jars to mobile phones (turn that old smartphone into a dedicated music-listening device, say).
• Don't be paranoid about use-by dates- test the food first by giving it a sniff.
• Get a reusable coffee cup.