Abstract:

Objective     To determine the contamination of ochratoxin A in millet and maize commercially available in Jinan.  Methods     An optimization study of the extraction solvent, testing conditions and recovery rates in detection of ochratoxin A in millet and maize by ELISA was carried out. Millet and maize samples collected from 5 districts of Jinan were analyzed under optimum conditions. Results      Optimal ochratoxin A extraction was obtained when the extracting agent contained 5% sodium chloride and 60% methanol. For all the samples, the ochratoxin A detectable rate in millet was 41%, while in maize it was 38%. The ochratoxin A detectable rate in millet from supermarkets was 56%, which was significantly higher than that in the millet samples from markets (26%) (P＜0.05). The ochratoxin A concentration level ranged between 0.40 and 4.45μg/kg, and the median was 1.67μg/kg. No significant difference in the ochratoxin A pollution level between millet and maize was found (P>0.05). Ochratoxin A contents in all samples were below the tolerance limit set by the state for ochratoxin A in grain. Conclusions     The millet and maize commercially available in Jinan are contaminated by ochratoxin A to some extent, but the ochratoxin A content in the detected samples is below the tolerance limit.

Key words: Ochratoxin A； Millet； Maize； Enzyme-linked immunosorbent assay