Submitted to: Mycotoxin Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/5/2006
Publication Date: 4/1/2006
Citation: Dorner, J.W., Lamb, M.C. 2006. Development and commercial use of afla-guard®, an aflatoxin biocontrol agent. Mycotoxin Research. 21:33-38. Interpretive Summary: Aflatoxin contamination of peanuts is a serious economic problem for peanut producers and processors and a food safety concern for consumers around the world. Contamination, which results from growth in peanuts by the molds, Aspergillus flavus and A. parasiticus, can occur in the field under drought conditions or in storage when peanuts are not maintained at safe moisture levels. Technology for biological control of aflatoxin contamination was previously developed that is based on competitive exclusion. It is carried out by applying a non-aflatoxin-producing strain of A. flavus to peanut soil where it competes with naturally-occurring, toxin-producing strains. This technology has been commercialized by Circle One Global, Inc., and the product, afla-guard®, received EPA section 3 registration as a biopesticide. Afla-guard® was used commercially for the first time on the 2004 peanut crop in the southeastern USA, and that use was monitored for efficacy. Results of the monitoring studies showed that applications of the biopesticide changed the composition of A. flavus soil populations so that those populations were dominated by the applied non-aflatoxigenic strain. In all areas that experienced aflatoxin contamination of farmers’ stock peanuts, use of afla-guard® resulted in major reductions in aflatoxin. Those reductions in aflatoxin carried through the storage period and resulted in major reductions in the aflatoxin content of shelled edible lots. The most important result from an economic standpoint was the dramatic reduction in the percentage of shelled lots rejected for the edible market that resulted from treatment with afla-guard®. Large-scale use of afla-guard® to control aflatoxin should provide a major economic benefit to the USA peanut industry while reducing the risk of aflatoxin consumption by consumers.
Technical Abstract: A biopesticide, afla-guard®, has been developed for controlling aflatoxin contamination in peanuts. This product provides the means of introducing a competitive, non-aflatoxigenic strain of Aspergillus flavus into soils where peanuts are being grown. The introduced strain competitively excludes toxigenic strains naturally present from invading developing peanuts. The biocontrol technology was made commercially available in 2004 by Circle One Global, Inc., upon receiving U. S. Environmental Protection Agency section 3 registration of afla-guard® as a biopesticide. The product was applied to approximately 2000 ha of peanuts in Georgia and Alabama during the 2004 crop year. Application of afla-guard® changed the composition of A. flavus soil populations from an average 71.1% toxigenic strains in untreated fields to only 4.0% in treated soils. Analyses of farmers’ stock peanuts being delivered at seven different locations showed a consistent reduction in aflatoxin contamination in peanuts from fields treated with afla-guard®. Over all locations, aflatoxin averaged 78.9 ng/g in untreated peanuts compared with 11.7 ng/g in treated peanuts, an 85.2% reduction. Peanuts from treated and untreated fields were stored together in separate warehouse bins at two different locations. Aflatoxin analyses at the Unadilla, GA location showed that 48.4% of shelled edible lots from untreated fields contained unacceptable levels of aflatoxin (>15 ng/g). At the Dawson, GA location, 15.8% of shelled lots from untreated fields contained >15 ng/g. At both locations, no shelled edible lots from treated fields contained >15 ng/g. Mean aflatoxin concentrations in edible peanuts from untreated and treated fields at Unadilla were 36.2 and 0.9 ng/g, respectively. At Dawson the respective means were 7.2 and 2.2 ng/g.