ABSTRACT
Ergosterol concentration was correlated with the number of fungal colonyforming units and aflatoxin in 40 corn samples. Ergosterol extraction was made through irradiation in a microwave oven, and quantification by high performance liquid chromatography (HPLC). The colony forming units were counted from the sowing of samples in DRBC culture medium at dilutions from 10-2 to 10-5 and next incubated for a period until 7 days at 28° C. Aflatoxin quantification was made by thin-layer cromathography. The ergosterol levels of the samples varied from 1.11 to 32.6 ppm, and the colony-forming units from 3.33 x 103 to 2.23 x 105. Presence of aflatoxins was noticed in 62.5 % of the samples. The correlation between the ergosterol quantity and the colony forming units was r = 0.94, demonstrating high relations between these variables. However, the correlation between ergosterol concentration and presence of aflatoxin showed to be low (r = 0.4). The results indicate that the determination of ergosterol levels represent a possibility of an evaluation of the corn's degree of fungal , in substitution of the counting technique of colony-forming units.
KEY WORDS:
Ergosterol; aflatoxin; fungi; corn; colony-forming units.
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