Australians waste an estimated 20 per cent of the food they buy. That's like one in five bags of groceries going straight to the bin.
But local government programs such as one being trialled in Leichhardt in Sydney targeting apartment dwellers could be a game changer for the way we think about food.
Leichhardt Council estimates that about 40 per cent of the waste from its household garbage bins is food. In 2007, it trialled a food collection service for apartment blocks that had more than 10 units and shared bins. Residents were given dedicated food waste bins that were emptied weekly; free kitchen bins; biodegradable bin bags, and information about what kind of material could go in the bins.
Now the council has asked researchers from the University of Technology, Sydney (UTS) to investigate ways of increasing the number of apartment residents who take advantage of the service.
The service is one way of extracting the river of gold – energy, water, nutrients – that flows through food waste, says Research Principal at UTS's Institute for Sustainable Futures (ISF), Jade Herriman.
"We waste an incredible amount of food," says Herriman. "That is food that is not being pulled out of the waste stream."
Along the way, vital nutrients such as nitrogen and phosphorous, and the energy and water used to grow food are also wasted. Left to rot, food generates methane, a potent gas that damages the atmosphere.
The food waste collected by Leichhardt Council is converted by a private contractor into a combustible gas similar to that which produces green electricity. The electricity is sold into the grid for distribution to domestic, commercial and industrial clients.
ISF is reviewing how the program has worked so far, whether residents are confused about the kind of waste to put in the bins, and whether there are barriers that stop them separating their food from general waste – such as worries about smell and vermin.
"Unless you are really passionate about it, it is easy to fall off the recycling bandwagon," says Herriman.
"But our waste is our wealth. We need to think about the embedded energy and water that is used to grow food, transport it and store it. That is all wasted if we throw our food away."
Many Australian councils mulch or shred garden waste, reusing it on their own parks and gardens or giving and selling it back to residents.
"With food there is a greater risk of odour and leachate," says Herriman. "Food waste can attract flies so there can be public health concerns. It is more regulated and recycling it isn't something councils can do themselves. Private contractors have to be engaged.
"We are in a period where councils are experimenting with different options."
Programs such as Leichhardt's are under way overseas but are not yet accepted practice.
Herriman says one of the surprising things she discovered was that in Australia, most food is wasted by residents rather than by supermarkets. But the bigger picture is one of food waste all down the chain, from the farmer to the consumer. We need to rethink how we grow, package, transport, market and consume food, she says.
Wasting food is not solely an Australian habit.
In the UK, a report commissioned by giant supermarket chain Tesco revealed its stores and distribution centres, in the first six months of 2013, generated 28,500 tonnes of food waste, 62 per cent of it from fruit, vegetables and bakery items. The retailer has since taken part in a roundtable discussion with university experts and sustainable food groups about how to cut that waste.
Explore further: A model approach for sustainable phosphorus recovery from wastewater