"During our research, we spoke to a farmer down in Victoria and he said to us, 'Whatever you do, don't touch the supermarkets … you'll go broke',"Mrs Cashen said.
"Whereas they'll tend to find the ones in the supermarket are picked quite green and they will change colour but they won't get sweeter."
Stories from farms and country towns across Australia, delivered each Friday.
Your information is being handled in accordance with the ABC Privacy Collection Statement.