Evaluation of potential biocontrol agent for aflatoxin in Argentinean peanuts

ALANIZ ZANON M.S.; CHIOTTA, M.L.; GIAJ-MERLERA G.; BARROS, G.; CHULZE, S.

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 162 p. 220 - 225

0168-1605

  Biocontrol by competitive exclusion has been developed as the most promising means of controlling aflatoxins in peanuts. A 2-year study was carried out to determine the efficacy of an Aspergillus flavus strain as biocontrol agent to reduce aflatoxin production in peanuts under field conditions in Argentina. The competitive strain used was a nontoxigenic A. flavus (AFCHG2) naturally occurring in peanut from Córdoba, Argentina. The inoculum was produced through solid-state fermentation on long grain rice and applied at rate of 50 kg inoculum/ha. The incidence of the released strain within the A. flavus communities in soil and peanuts was determined using the shift in the ratio toxigenic: nontoxigenic and VCG analysis. During 2009/2010 growing season, treatments produced significant reductions in the incidence of toxigenic isolates of A. flavus/A. parasiticus in soil and peanuts. However, no preharvest aflatoxin contamination was observed. In 2010/2011 growing season, plants were exposed to late season drought conditions that were optimal for aflatoxin contamination. Significant reductions in aflatoxin levels averaging 71% were detected in treated plots with different inoculation treatments. The results suggest that A. flavus AFCHG2 can be applied using the strategy of competitive exclusion to reduce aflatoxin contamination in Argentinean peanuts.  Biocontrol by competitive exclusion has been developed as the most promising means of controlling aflatoxins in peanuts. A 2-year study was carried out to determine the efficacy of an Aspergillus flavus strain as biocontrol agent to reduce aflatoxin production in peanuts under field conditions in Argentina. The competitive strain used was a nontoxigenic A. flavus (AFCHG2) naturally occurring in peanut from Córdoba, Argentina. The inoculum was produced through solid-state fermentation on long grain rice and applied at rate of 50 kg inoculum/ha. The incidence of the released strain within the A. flavus communities in soil and peanuts was determined using the shift in the ratio toxigenic: nontoxigenic and VCG analysis. During 2009/2010 growing season, treatments produced significant reductions in the incidence of toxigenic isolates of A. flavus/A. parasiticus in soil and peanuts. However, no preharvest aflatoxin contamination was observed. In 2010/2011 growing season, plants were exposed to late season drought conditions that were optimal for aflatoxin contamination. Significant reductions in aflatoxin levels averaging 71% were detected in treated plots with different inoculation treatments. The results suggest that A. flavus AFCHG2 can be applied using the strategy of competitive exclusion to reduce aflatoxin contamination in Argentinean peanuts.