Submitted to: Journal of Food Additives & Contaminants
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/29/2001
Publication Date: N/A
Citation: Interpretive Summary: Deoxynivalenol (DON) is a toxin produced by a mold that is a common pathogen of cereal grains worldwide, in particular wheat, barley, and maize. DON causes substantial losses to U.S. agriculture through reduced grain quality, reduced feed efficiency of domestic animals, and through the costs of monitoring food. While a variety of methods for detection of DON in cereal grains have been developed, rapid and accurate methods are urgently needed, as cited in a recent GAO report (GAO/RCED-99-59). This research describes the development of a rapid, sensitive assay for DON in wheat. The method compares well to a more established analytical procedure for DON in wheat (HPLC-UV) and will be useful for detecting DON in this commodity.
Technical Abstract: The mold Fusarium graminearum is found worldwide as a pathogen of cereal grains, in particular wheat and maize, and produces a mycotoxin known as deoxynivalenol (DON or vomitoxin). Each year the presence of this compound and related trichothecenes causes substantial losses to agricultural productivity. Rapid methods for measurement of this toxin in grains are required to monitor and effectively divert contaminated grain from the food supply. A fluorescence polarization immunoassay using a previously described monoclonal antibody for DON was developed. The assay was based on the competition of unlabeled DON, from a sample, with a fluorescently tagged DON (DON-FL) for a DON-specific monoclonal antibody in solution. The fluorescence polarization (FP) of the tagged DON was increased upon binding with the antibody. In the presence of free toxin, less of the DON-FL was bound and the polarization signal was decreased. The assays were very simple to perform, requiring only mixing of an aqueous extract of wheat with the DON-FL and antibody. The sensitivity of the assay was strongly dependent upon the time between mixing of the sample with the tracer and measurement of the fluorescence polarization, with midpoints for the competition curves ranging from 0.15 ppm with a 15 sec incubation to over 5 ppm with a 12 min incubation. Samples of wheat naturally contaminated with DON were evaluated by FP and by an HPLC-UV method, with a good correlation (r2=0.97). Although the FP method tended to slightly overestimate DON in the wheat samples, by roughly 20%, the assay was easy to use and was very useful for screening of wheat.