PROTECTING agricultural land was the topic of the day at the Heart Foundation and Food Alliance planning for food forum.
A panel of experts discussed changes to planning legislation that would allow prime green wedge land around Melbourne to be sucked up by housing development.
A Bill to make changes to farming and rural zoning in state Parliament at the moment.
RMIT University Professor urban expansion expert Michael Buxton said the Bill was the biggest threat to green wedges in the history of Melbourne planning.
"We're at a critical turning point where 40 years of planning will be thrown out,'' Prof Buxton said.
"These changes will attract major developers and farming will become less viable and ultimately unviable.''
Prof Buxton said Minister for Planning Matthew Guy had actively encouraged councils to reduce their minimum size for sub-division lots.
"It turns the area into a haven for the development of leisure and recreation facilities, especially in areas like the Yarra Valley,'' he said.
"Why would farmers keep going if they can get a lot of money to sell?''
Supermarket monopolies were also a fiery topic.
Food security expert from Wayne University, Detroit, Kami Pothukuchi spoke to the forum from Michigan.
Dr Pothukuchi said it was essential to treat fresh food as a public good and basic human right.
"For this reason everyone must have orderly, fair and clean access to it,'' she said.
"The monopoly of the food system needs to end to allow a greater resilience in the food industry through greater dispersal of food outlets.''
South Australian Department of Planning, Transport and Infrastructure managing director Jason Ting said agriculture accounted for 36 per cent of South Australia's merchandise exports.
"It is a significant economic contributor, providing $15.5 billion in total revenue per year,'' Mr Ting said.
"It also accounts for 145,000 jobs, which is 18 per cent of the employed workforce.
"This is why we need to work hard to protect it.''