Detection of Fumonisins in Fusarium Cultures, Corn, and Corn Products by Polyclonal Antibody-Based ELISA: Relation to Fumonisin B1 Detection by Liquid Chromatography.

A specific sheep polyclonal antiserum was applied to the competitive direct enzyme-linked immunosorbent assay (CD-ELISA) of fumonisins in Fusarium cultures, fresh corn, animal feed, and human foods, and the results were related to fumonisin B1 (FB1) levels determined by liquid chromatography (LC). The limit of detection of FB1 for the CD-ELISA was 0.1 ng/ml. Cross reactivity (defined as [ng/ml FB1 required for 50% inhibition]/[ng/ml of analogue required for 50% inhibition] × 100) for the antiserum in the ELISA was 100, 24, and 30%, for FB1 FB2, and FB3, respectively. FB1 was detected in F. moniliforme cultures grown on corn (≤760 µg/g) but not in those for F. graminearum . Fumonisin estimates were 2.8-fold higher by CD-ELISA than FB1 estimates by LC. Upon using the antiserum in a commercial CD-ELISA format (Veratox), mean recovery of FB1 from spiked corn (0.1 to 3 µg/g)was 85.2 ± 25.3%, whereas the mean recovery by LC was 74.1 ± 6.2%. Analyses of 43 fresh corn, 28 animal feed, and 14 human food samples revealed that estimates of total fumonisins by the commercial ELISA were 2.9-, 2.2-, and 1.3-fold higher than FB1 values determined by LC. For each sample type, the ELISA significantly correlated with LC (r > 0.9; P < 0.05). Taken together, the results suggest that the polyclonal antibody-based CD-ELISA could be a reliable first-tier screening procedure for fumonisins in corn, animal feed, and human food when used in conjunction with LC confirmation. The differences between the two methods suggests the further presence of FB2 and FB3 or structurally related compounds.

Comparative Assessment of Fumonisin in Grain-Based Foods by ELISA, GC-MS, and HPLC.

Seventy-one (71) food samples were analyzed for the mycotoxin fumonisin by a monoclonal antibody based competitive enzyme-linked immunosorbent assay (ELISA). Fumonisins were detected primarily in corn-based products with 7/12, 2/2 and 1/3 and 1/7 yellow cornmeal, blue cornmeal, corn muffin mix, and mixed grain cereal samples yielding positive results, respectively. When the positive samples and randomly selected negative samples were assessed by other methods, correlations (r values) between ELISA and gas chromatography-mass spectrometry (GC-MS), ELISA and high-pressure liquid chromatography (HPLC) and GC-MS and HPLC were 0.478 (p < 0.05), 0.512 (p < 0.05), and 0.946 (p < 0.01), respectively. The results suggested that although the immunoassay could be used for screening of fumonisin in food samples, higher estimates were attained by ELISA than by the other two methods particularly in the more contaminated samples. These observations may result from differences in sample preparation among the methods or because of the presence of structurally related compounds in extracts that are detectable by ELISA but not the other two methods.