Sensitive ELISA Test for Determination of Ochratoxin A

A direct, competitive enzyme-linked immunosorbent assay (ELISA) with monoclonal antibody has been developed for quantitative determination of ochratoxin A (OA) in different cereals. A dichloromethane/citric acid mixture was used for extraction of cereals. This cleanup procedure proved to be as effective for ochratoxin A extraction as protocols using strong acids. The mean within-assay and interassay coefficients of variation for the standard curve was <10%. The range of this test is 1−10 ng/g, with a detection limit of 0.5 ng/g OA. The toxin recovery from cereals infected with 5−100 ng/mL OA varied between 90 and 130%. Keywords: Ochratoxin A; ELISA; cereals