DETERMINATION OF HYDROLYZED FUMONISIN B-1 (HFB1) IN CORN BY COMPETITIVE DIRECT ENZYME-LINKED-IMMUNOSORBENT-ASSAY

Fumonisin B-1, a mycotoxin produced by certain Fusarium moulds, consis ts of two tricarballylic acid groups esterified to a 20-carbon backbon e. Under alkaline conditions, or through metabolism, the aminopentol b ackbone, also known as hydrolysed Fumonisin B-1 (HFB1) can be formed a nd is itself cytotoxic. Although the occurrence of HFB1 1 in corn-base d foods is suspected, because of the ubiquitous nature of FB1 in corn, analytical methods for its detection are difficult. In the present re port 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 bindin g 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-phosph ate buffered saline. The antibody also cross-reacted with the hydrolys is 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 fu monisins, 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 th is matrix. The CD-ELISA provides a sensitive and rapid tool for the an alysis of corn-based foods for HFB1.