|Hagler, JR., Winston - NC STATE UNIVERSITY|
Submitted to: Journal of Association of Official Analytical Chemists International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 9, 2000
Publication Date: October 1, 2000
Citation: WHITAKER, T.B., HAGLER, JR., W.M., JOHANSSON, A.S. SAMPLING, SAMPLE PREPARATION, AND ANALYTICAL VARIABILITY ASSOCIATED WITH TESTING WHEAT FOR DEOXYNIVALENOL. JOURNAL OF ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS INTERNATIONAL. 2000. v. 83. p. 1285-1292. Interpretive Summary: Deoxynivalenol (DON) is a toxic compound produced by molds found in several grains. The Food and Drug Administration has established an advisory limit to control the maximum quantity of DON found in food and feed products. As a result, grain products are inspected by processors and manufacturers to detect and remove contaminated lots from the food and feed dchain. It is difficult to determine levels of DON in large shipments because of the errors associated with sampling, sample preparation, and analysis, collectively called the DON test procedure. Errors in the test procedure result in some lots being misclassified. Some of the good lots test bad and some of the bad lots test good. The errors associated with measuring DON in wheat were determined. Once the magnitude of the testing errors is known, cost-effective methods can be developed to reduce the testing errors which will reduce the number of lots misclassified. This will reduce both health risks to the consumer and economic loss to the processor.
Technical Abstract: The variability associated with testing wheat for deoxynivalenol (DON) was measured using a 0.454 kg sample, Romer mill, 25 g comminuted subsample, and the Romer Fluoroquant analytical method. The total variability was partitioned into sampling, sample preparation, and analytical variability components. Each variance component was found to be a function of the DON concentration and equations were developed to predict each variance component using regression techniques. The effect of sample size, subsample size, and number of aliquots on reducing the variability of the DON test procedure was also determined. For the test procedure described above, the coefficient of variation (CV) associated with the testing of wheat at 5 ppm was found to be 13.4%. The CV associated with sampling, sample preparation, and analysis was 6.3, 10.0, and 6.3%, respectively. The CV associated with testing wheat are relatively small when compared to CV associated with testing other commodities for other mycotoxins such as aflatoxin in peanuts. Even using the small 0.454 kg sample of wheat, the sampling variation was not the largest source of error, as often found in other mycotoxin test procedures.