ANALYSIS OF FUMONISIN B-1 AND ITS HYDROLYSIS PRODUCT IN TORTILLAS

Fumonisins are toxic metabolites of Fusarium moniliforme, a fungus tha t occurs widely in corn, Fumonisins cause leukoencephalomalacia in hor ses and pulmonary edema in swine and have been suggested as a possible cause of an increased incidence of neural tube defects among people l iving along the Texas-Mexico border. As part of an effort to determine levels of fumonisins in human food, a liquid chromatographic (LC) met hod was devised for determining fumonisin B-1 (FBI) and the total hydr olysis product of FB1 (HB1) in tortillas. The method uses acetonitrile -0.1M phosphate buffer (pH 3; 1 + 1)extraction, solid-phase C-18 clean up, o-phthalaldehyde and 2-mercaptoethanol derivatization, and reverse d-phase LC. Average recoveries from tortillas spiked with FB1 and HB1 at 250, 500, and 1000 ng/g were 86.5% for FB 1 and 82.6% for HB1. Tort illas (54) and masa (8) from the Texas-Mexico border were analyzed for FB1 and HB1. Average amounts of FB1 and HB1 in tortillas were 187 and 82 ng/g, respectively. Average amounts of FB1 and HB1 in masas were 2 62 and 64 ng/g, respectively. The results show that fumonisin B-1 and its hydrolysis product are present in tortillas consumed by a populati on experiencing an increased incidence of neural tube defects.