The food that diners leave behind on their plates might soon be recycled to earn profits, create jobs and further develop Australia's burgeoning aquaculture industry.
University of Queensland scientists have conducted a successful pilot study feeding a prized culinary delicacy, the red claw crayfish, on a substitute diet using processed food scraps from two Brisbane restaurants.
"We used waste like potato peelings and the vegetables and salads that people left on their plates," said the Manager of the UQ Aquaculture Research Facility at Pinjarra Hills, Dr Ian Johnson.
"This is one case where researchers are happy when people don't eat their vegetables. We'd like it if they didn't eat their steak too."
Dr Johnson said the low-budget UQ project proved that it was practical and potentially profitable to use restaurant waste as aquaculture feed.
The project demonstrated that there was no statistical difference in size between crayfish grown for three months on processed restaurant waste at negligible cost, and those grown on commercial feed, costing $30/25kg. All reached the commercial size range.
"Food waste is abundant, and it's estimated that about 100,000 to 120,000 tonnes of scraps are generated by restaurants and households in Brisbane alone, each year," he said.
"It's also inexpensive, and restaurants in fact pay contractors about $35-$45 a tonne to take it away, where it largely goes to land fill, contributing to Greenhouse gas production.
"Food waste is a viable substitute for commercial feed for detritivorous animals such as crayfish, freshwater prawns and some fish.
"Some other products that might benefit from using this waste include table fish, and coarse fish which could be recycled for fish meal, pet food, fish feeds and fertilizer.
"We could be reusing high volume restaurant waste in an environmentally-friendly way and cutting aquaculture production costs.
"Even the pond sludge can be recyled as a nutrient-rich topsoil. "
Dr Johnson said red claw crayfish were in high demand, both in Australia and internationally, as Australian crayfish were succulent and free of major diseases. The Australian market could easily absorb another 100 tonnes of crayfish a year.
Dr Johnson is seeking sponsorship to conduct further research on recycling restaurant waste using different species and a variety of growing conditions.
He will discuss profiting from waste in aquaculture at the second Queensland Warmwater Aquaculture Conference on the weekend of April 21 and 22 at the University's St Lucia campus. The conference is being hosted by the University's Centre for Marine Studies, and Aquaculture Information Technologies.
Leaders from the aquaculture field will discuss the status and potential of Queensland's major aquaculture industries and will provide investors and other interested parties with an overview of aquaculture in the Queensland market.
Staff of The University of Queensland held Queensland's first aquaculture conference in 1984, after the University's then Animal Husbandry Department came up with the idea of farming freshwater crayfish, and performed the basic research that was a catalyst for starting the industry in the State.
Two of the original researchers, Dallas Baker and Robin Hutchings took the lead and formed the first Queensland crayfish farm.
Mr Hutchings, a UQ Bachelor of Science graduate, and manager of Freshwater Australian Crayfish Traders of Tarome will discuss commercial redclaw production at this year's conference.
Discussion topics will also include: prawn farming in Queensland, freshwater finfish production, silver perch industry, aquarium fish culture, world aquaculture in review, barra farming and industry trends.
For further information, or to register for the conference, contact Dr Ian Johnson at the Aquaculture Research Facility, telephone 07 3365 5469, email: i.johnson@mailbox.uq.edu.au
Media: For further information, contact Dr Ian Johnson, telephone 07 3365 5649, mobile 0411 285 476 Robin Hutchings, telephone 5463 8226, Jan King at UQ Communications 0413 601 248.
Garlic Redclaw in Wine Sauce
(Ian Johnson recipe)
Ingredients:
2 kg fresh redclaw
6 bay leaves
_ - 1 cup spiced wine (white wine if preferred)
_ - 1 cup cream
5 - 6 cloves garlic (more or less according to personal taste)
2 - 3 eschalotts or small spring onions, finely diced
_ teaspoon chili powder (optional)
Method:
Cook crayfish in plenty of heavily salted water (as for prawns or crabs) with bay leaves until shells are red (1 - 2 minutes at boil - as with all shellfish, prolonged cooking toughens the flesh).
Chill in iced water to prevent further cooking
Shell crayfish and remove vein (gut) if wild caught
Dice tail meat if crayfish are large
Cook garlic and eschalotts briefly in very hot oil, add crayfish meat and move around until heated through
Add wine and simmer briefly
Thicken with cream
Serve with steamed rice
