COMPARISON OF THIN-LAYER CHROMATOGRAPHY AND COMPETITIVE IMMUNOASSAY METHODS FOR DETECTING FUMONISIN ON MAIZE

The fumonisin mycotoxins are secondary metabolites of Fusarium moniliforme, which are common worldwide in maize. Thin-layer chromatography (TLC) and competitive indirect immunoassay (CI-ELISA) methods were compared for detection of fumonisin B-1 in maize. Corn from the 1991 Missouri maize variety trials (322 samples) was collected, milled, subsampled, and analyzed independently by two laboratories using different screening methods. Fifty-two percent of the samples tested negative for fumonisin B-1 at 1 ppm by both methods. By TLC, an additional 14% of the samples had less than 1 ppm of fumonisin B-1 and more than 1 ppm by CI-ELISA. TLC found 34% of the samples were from 1 to 10 ppm and only 1% of the samples were above 10 ppm of fumonisin B-1. CI-ELISA found 28% of the samples contained fumonisin levels between 1 and 10 ppm and 20% had greater than 10 ppm of fumonisin. In the remaining samples, CI-ELISA consistently reported higher fumonisin levels than TLC (160/322), while TLC was higher in only 10 of 322 samples. The discrepancy may be due to fumonisin B-1 alone being detected by TLC, while CI-ELISA measures total fumonisins. Both methods are well suited for rapid screening of maize samples for fumonisin contamination.