By Emma Leonard
Queensland researchers have developed a web-based decision-support tool to help peanut growers assess when to harvest for maximum returns and minimal aflatoxin contamination.
Achieving the optimum harvest time for peanuts can mean the difference between low aflatoxin levels and optimal market price (about $650/tonne) or a high aflatoxin level and a price penalty up to $450/tonne.
The new support tool, called AFLOMAN, has been developed by a team at Queensland Department of Primary Industries and Fisheries (QDPIF).
Aflatoxins are a group of naturally occurring toxins produced by two soil-dwelling fungi. Found in a wide range of products including peanuts, at high concentrations aflatoxins can cause liver damage.
In Australia aflatoxins do not present a health risk due to thorough screening procedures carried out at various stages in the food chain. "The risk of aflatoxin production is greatest in years which suffer an end of season drought while soil temperatures remain above about 22oC," explains Graeme Wright, project leader for the peanut research team at QDPIF, Kingaroy.
"Under these conditions it is essential that the crop is pulled earlier than normal, before peanuts reach around 30 percent pod moisture content, because aflatoxin production can occur from 15 to 30 percent pod moisture content.
"Our research shows that in a high risk year for aflatoxin production, harvesting a full season variety such as Streeton at 139 days after planting resulted in an aflatoxin level of about 60 parts per billion (ppb), whereas delaying the harvest by two weeks meant the level shot up to over 400ppb."
AFLOMAN draws on five years of GRDC-funded research and any peanut grower can access the service by registering at the website (www.apsim.info/apsim/afloman).
Once registered it is just a matter of entering the soil type, sowing date and variety information for each paddock. As harvest approaches, growers log daily rainfall, ambient and soil temperatures and input this information into the web-based software. AFLOMAN analyses the information and emails the grower an aflatoxin risk report.
Graeme Wright says there is also extension support to help peanut growers use AFLOMAN.
For more information:
Graeme Wright, 07 4160 0734, email@example.com
GRDC Research Code: DAQ 543, program 2