Maize in Mexico, basically used for human consumption, is stored for variable periods of time and underdiverse environmental conditions which favor infestation byinsects and fungi. The toxicogenic capacity of the latterdetermines the interest to know about their behaviour duringstorage. In this study, it was determined the temperature effect,inoculum concentration and the integrity of grain on aflatoxin synthesis by Aspergillus parasiticus in three maize hybridsunder simulated storage conditions. Three maize hybrids withnatural and artificial field infestation and re-inoculated in thelaboratory were stored at 27 and 33°C. The results indicatedthat: 1) Fusarium sp. was the predominant fungus undernatural infestation, and A. parasiticus under artificial infestation; 2) The levels of aflatoxin increased at both storage temperatures; 3) As inoculum of A. parasiticus increases,there is a greater quantity of aflatoxin; and 4) Aflatoxin levels were lower at 33°C when the predominant fungus was Fusarium. The results showed the importance of the fungali noculum density and temperature during storage in the synthesis of maize aflatoxin. It is suggested grain cleaning practices and storage in cool and dry places to reduce oravoid aflatoxin synthesis
Keywords: Aspergillus parasiticus, Fusarium sp.,maize storage, temperature effect, inoculum level.