Tracing the cycle of food waste in order to break it

Australians waste nearly 50% of the food they buy - about 4.1 million tonnes per year or 9 kg of food from every home, every week. This increases our carbon footprint through transport costs and greenhouse gases from decomposition. Researchers from the University of South Australia (UniSA) have now traced the cycle of food waste in a three-year Australian Research Council (ARC) project.

Reducing household food waste has proved difficult because the reasons for over-purchasing are not rational; they have strong emotional and cultural determinants. Thus, changing this behaviour requires understanding food purchase, preparation, recycling and disposal as sociocultural and economically determined behaviour. ‘Zeroing in on Food Waste: Measuring, understanding and reducing food waste’ was conducted as part of a collaboration with Central Queensland University, Flinders University, the Local Government Association of SA and Zero Waste SA.

UniSA PhD candidate Christian Reynolds and the research team estimated the breakdown of food waste from farm to beyond the household using an economic modelling technique known as input-output material flow analysis, which allowed him to trace the wastage of food throughout the supply chain. Reynolds based his initial figures on the ‘National Waste Report 2010’, which was produced by the intergovernmental National Environment Protection and Heritage Council.

Having undertaken economic, environmental and psychological modelling of food wastage in South Australia, the researchers now know exactly what we waste, how it is wasted and where it goes. Households are said to be the worst culprits, accounting for more than half Australia’s 7.3 million tonnes of food waste every year. Retailers, restaurants, wholesalers and the education sector round out the top five.

The researchers also found that Adelaide people are some of the most resourceful recyclers of food waste: all metropolitan councils but one now collect food waste in kerbside green wheelie bins and turn it into compost. Some families are creatively re-using their food waste, with an average of 3.2 kg of food waste per week per household being diverted to ‘informal disposal’.

Adelaide resident Luigi Cirocco and his family are minimising their food waste by buying and cooking carefully, and composting or feeding scraps to their six chickens. Cirocco said the family uses compost “to replenish the soil and a worm farm to harvest worm castings and the associated beneficial bacteria”. Meanwhile, the chicken eggs are “incorporated into value-added products, like pasta or lasagne”.

Reynolds is one of 12 early-career scientists unveiling their research to the public for the first time thanks to Fresh Science, a national program sponsored by the Australian Government through the Inspiring Australia initiative. “Now that we have identified the top food wasters,” he said, “we can tailor programs to reduce food waste in each sector.”