Determination of hydrolysed fumonisin B1 (HFB1) in corn by competitive direct enzyme-linked immunosorbent assay

Fumonisin B1, a mycotoxin produced by certain Fusarium moulds, consists of two tricarballyic acid groups esterified to a 20-carbon backbone. Under alkaline conditions, or through metabolism, the aminopentol backbone, also known as hydrolysed Fumonisin B1 (HFB1) can be formed and is itself cytotoxic. Although the occurrence of HFB1 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 2ng/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 HFB1 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 the matrix. The CD-ELISA provides a sensitive and rapid tool for the analysis of corn-based foods for HFB1.