Submitted to: Journal of the Association of Official Analytical Chemists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2005
Publication Date: N/A
Interpretive Summary: Aflatoxin and fumonisin are carcinogenic and /or toxic compounds produced naturally in the environment by fungi. The Food and Drug Administration has established maximum limits for both aflatoxin and fumonisin in corn and corn products. The grain industry has established mycotoxin control programs to detect and remove contaminated grain from both the domestic and export markets. Sampling methods are used to predict quality (grade) factors and levels of mycotoxins in agricultural commodities in bulk shipments. It is difficult to get an accurate estimate of the true aflatoxin and fumonisin concentration in a contaminated lot using sampling methods because so few kernels are contaminated (1 in 1000). In this study, aflatoxin and fumonisin were shown to be concentrated in the low quality grade components, which may reduce the uncertainty of using sample results to estimate the true lot concentration. Equations were developed to predict the aflatoxin and fumonisin levels in a bulk lot from measurements of aflatoxin and fumonisin in the low quality grade components. Results from this study may lead to a more rapid and more accurate method of estimating aflatoxin and fumonisin in bulk corn lots.
Technical Abstract: A study was conducted to determine if aflatoxin and fumonisin are concentrated in the poor quality grade components of shelled corn. Four 1.0 kg test samples were each taken from twenty-three lots of shelled corn marketed in North Carolina. Inspectors from the Federal Grain Inspection Service (FGIS) divided each test sample into three grade components: 1) damaged kernels (DM), 2) broken corn and foreign material (BCFM), and 3) whole kernels (WH). The aflatoxin and fumonisin concentration was measured in each component and a mass balance equation was utilized to calculate the total concentration of each mycotoxin in each test sample. Averaged across all test samples, the aflatoxin concentration in the DM, BCFM, and WH components was 1300.3, 455.2, and 37.3 ppb, respectively, and accounted for 52.5, 7.3, and 40.2 % of the total aflatoxin mass in the test sample. Averaged across all test samples, the fumonisin concentration in the DM, BCFM, and WH components was 148.3, 51.3, and 1.8 ppm, respectively, and accounted for 68.1, 9.4, and 22.5 % of the total fumonisin mass in the test sample. Averaged across all test samples, the DM, BCFM, and WH components accounted for 3.6, 1.4, and 95 % of the sample mass, respectively. The DM and BCFM components combined accounted for only 5.0% of the test sample mass, but accounted for 59.8% and 77.5% of the total aflatoxin and fumonisin mass in the test sample, respectively. Correlation analysis determined that aflatoxin mass (ng) in the combined DM and BCFM components was a better predictor of aflatoxin concentration in the test sample (lot) than the aflatoxin concentration (ng/g) in the combined DM and BCFM components. Similar results were obtained for fumonisin. Using regression analysis, equations were developed to predict the aflatoxin and fumonisin concentrations in a lot by measuring the aflatoxin and fumonisin mass in the combined DM and BCFM grade components. This study indicated that measuring either aflatoxin or fumonisin in the combined DM and BCFM grade components could be used as a screening method to predict either the aflatoxin or the fumonisin in a bulk lot of shelled corn.