Airtight storage of maize: its effect on fungal infection and aflatoxin production

摘要

The effects of airtight storage on fungal infection and afiatoxin production of maize were investigated. Maize 'CPI-2' was placed in polyethylene bags (2 kg/bag) under airtight Conditions (initial 02 content was 1.4 +- 0.1%). The maize was stored for six months under warehouse conditions. Three replicates were used for each treatment. The initial moisture contents (MCs) of maize in the bags were 14 +- 0.3%, 17 +- 0.2% and 20 +- 0.2%. As controls, maize samples with the same initial MCs were placed in polyethylene bags under normal conditions (air) with 0_2 content of 21%. Each bag was arranged horizontally and randomly on a wooden table. The Aspergillus flavus population was determined through isolation using a dilution method followed by plating on Aspergillus fiavus and parasiticus agar (AFPA), while dichloran 18% glycerol agar (DG18) was used for isolation of other storage fungi. Aflatoxin content was determined using thin layer chromatography (TLC). The results showed that the total fungal population, population of A.fiavus, and total afiatoxin B_l content in maize with the three initial MCs packed under normal conditions were higher than under airtight conditions. The total fungal population in maize with initial MCs of 14 and 17% increased with the increase of storage duration, while the population in maize with initial MC of 20% fluctuated. The population of A. fiavus on maize fluctuated during storage in all treatments. Total afiatoxin B_l content increased with the increase of storage duration.