Airline food has come a long way over the years. Book with the right airline and you’ll find three-course dinners, branded snacks and – most shocking of all – real vegetables.

But what happens to the food that isn’t eaten? Historically, all leftover airline meals were binned and burned at the end of each flight – but one forward-thinking enterprise in Australia is turning all of its wastage into meals for the homeless.

OzHarvest already collects unwanted food from more than 2,000 Australian organisations – such as supermarkets, hotels, wholesalers and corporate events – and redistributes it free of charge to local charities. But now it has teamed up with Brisbane Airport to gather uneaten packets of biscuits, muesli bars, sandwiches and fruit – up to 400kg every day.

The food mostly comes from cancelled flights, OzHarvest’s Queensland manager Cameron Hickey told ABC News. “We collect the food that didn't end up on the flight or did end up on the flight but hasn't been opened,” he said.

“There are many delicious meals in first class that aren't eaten, which often means there's excess food along the supply chain. Pretty much anything you're seeing on an airline is something we can redistribute, as long as it's still in a fit state to eat.”

According to the United Nations Environment Programme (UNEP), a third of all food is lost or wasted worldwide. Food loss and waste globally costs up to US$940 billion (£72 billion) per year, and more than 800 million people are undernourished.

Inflight meals – like this one by Qantas – have certainly improved over the years

So why aren't more airports and airlines working with charities? Denver International Airport has a similar food donation scheme, but in most destinations it is forbidden to take unwanted plane food off airport property for safety reasons. It is usually doled out to hungry airline staff and maintenance crew, but there are heavy penalties for anyone who takes it off-site. However, by working directly with the airport – and only collecting sealed packets – OzHarvest are able to meet health and safety standards. It’s a refreshing triumph of ingenuity over red tape.

“We plan on reducing food waste by 50 per cent by 2025,” OzHarvest founder Ronni Kahn told journalists. “That's the goal.” To date, the organisation has delivered 50,671,401 meals to charities.

Free soup in #Perth CBD made from rescued produce. A few politicians around too. Thanks @OzHarvest #ShadowWineBar! pic.twitter.com/DyOLHPCPO8 — Hayley Roman (@hayleyroman) July 25, 2016

In Brisbane, OzHarvest – a partner of UNEP – sends two vehicles daily to collect the leftover food from the airport. “Within two hours of us picking up the food, it's delivered to a charity for the homeless,” said Hickey. “Sometimes it's really funny when we drop some of the first class food to the charities as they think we're kidding.”

It’s a win-win situation for airlines, too, as OzHarvest works with them to reduce their food wastage in general. The organisation keeps a record of the food donated by airlines – noting the types, quantities and use-by dates. “With that data many of the airlines have seen a drop in excess food and are tightening their food waste,” Mr Hickey said. “Our aim is to show them where the gaps are, and if we can help tidy up airlines and help them get more efficient, then we'll move onto another industry and go there.”

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OzHarvest, which was set up in 2004, redistributes unwanted food in Sydney, Adelaide, Brisbane, Canberra, Gold Coast, Melbourne, Newcastle and Perth, and plans to work with more airports in the future. Its regional food rescue programme REAP works in communities outside of the cities.

Ronni Kahn set up OzHarvest after being horrified by the amount of surplus food from her events business; she would deliver the excess to a homeless shelter rather then let it go to waste. In 2010, she was named Australian of the Year for her work.