Effect of metal ions on aflatoxin production by Aspergillus parasiticus.

The effect of iron, copper, cobalt, cadmium, zinc, molybdenum, magnesium and manganese salts was studied on aflatoxin production in relation to mycelial mass. Iron, copper and cadmium salts decreased the aflatoxin production to different levels but a mixed trend was observed depending on salt concentration, with molybdenum, magnesium and manganese. Cobalt and zinc salts stimulated aflatoxin production at all concentrations studied. The maximum increase in aflatoxin production, 655% and 519% was observed in the presence of zinc sulfate and sodium molybdate, respectively. A negative correlation was observed between aflatoxin production and vegetative growth of fungus.