Stimulation of Aflatoxin Formation in Maize Seeds

Abstract

Aflatoxin production by Aspergillus flavus was measured when cultivated alone and when paired with either A. niger, A. oryzae, Penicillium viridicatum, Fusarium graminearum [Gibberella zeae], Hyphopichia [Pichia] burtonii or Bacillus amyloliquefaciens in irradiation-sterilized maize seeds at 3 water activities (0.98, 0.95 and 0.90 aw) and 25 degrees C. Compared with pure culture, aflatoxin production in mixed culture with filamentous fungi was decreased at 0.98 aw but was enhanced at 0.90 aw. Both P. burtonii and B. amyloliquefaciens markedly stimulated aflatoxin production, especially at 0.95 and 0.98 aw. The importance of microbial interaction in toxin production in living seeds is discussed.