Determination of hydrolysed fumonisin B-1 (HFB1) in corn by competitive direct enzyme-linked immunosorbent assay

Fumonisin B-1, a mycotoxin produced by certain Fusarium moulds, consists of two tricarballylic acid groups esterified to a 20-carbon backbone. Under alkaline conditions, or through metabolism, the aminopentol backbone, also known as hydrolysed Fumonisin B-1 (HFB1) can be formed and is itself cytotoxic. Although the occurrence of HFB1 1 in corn-based foods is suspected, because of the ubiquitous nature of FB1 in corn, analytical methods for its detection are difficult. In the present report we describe a monoclonal antibody-based competitive direct enzyme-linked immunosorbent assay (CD-ELISA) for the rapid analysis of HFB1 in corn. The concentration required to inhibit enzyme conjugate binding by 50% (IC50) was 36 ng/ml. The limit of detection of HFB, by the CD-ELISA was 2 ng/ml, when HFB1 was added in bovine serum albumin-phosphate buffered saline. The antibody also cross-reacted with the hydrolysis products of FB2, FB3, and FB4, having IC50 values of 331, 174, and 1700 ng/ml respectively. The antibody did not react with the intact fumonisins, sphingosine, sphinganine, or tricarballylic acid. Samples of corn spiked with HFB 1 over the range of 5-1000 ng/g indicated the CD-ELISA has a limit of detection of 5 ng/g and an IC50 of 41 ng/g in this matrix. The CD-ELISA provides a sensitive and rapid tool for the analysis of corn-based foods for HFB1.