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United States Department of Agriculture

Agricultural Research Service

Title: Estimating Aflatoxin in Farmers' Stock Peanut Lots by Measuring Aflatoxin in Various Peanut Grade Components

Authors
item Whitaker, Thomas
item Hagler Jr, Winston - NCSU
item Giesbrecht, Francis - NCSU
item Dorner, Joe
item Dowell, Floyd
item Cole, Richard

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 1997
Publication Date: N/A

Interpretive Summary: Aflatoxin is a naturally occurring carcinogenic and toxic compound found in many agricultural commodities. Maximum aflatoxin levels allowable in food products are established by the FDA. The peanut industry has an aflatoxin control program that attempts to detect and remove aflatoxin contaminated peanuts from the edible market. The peanut industry wants to improve the current aflatoxin control program by testing peanuts for aflatoxin at the first point of sale or when farmers bring their peanuts to the buying point. Aflatoxin is more likely to be found in damaged kernels, small kernels, and kernels that have broken loose from the peanut pod (high risk components) than in the sound mature kernels. As a result, the peanut industry is interested in developing an aflatoxin sampling program for farmers' peanuts by measuring aflatoxin only in the high risk components. Studies were conducted to determine which high risk component or combination of components are the most accurate predictor of the aflatoxin in the farmer's peanut lot. The most accurate predictor of the aflatoxin in the farmer's lot was the combined aflatoxin in all three high risk components. Next, the ratio of aflatoxin in the high risk components to the aflatoxin in the entire lot was also determined. Results will help regulatory agencies and the peanut industry design cost effect sampling plans to accurately detect and remove aflatoxin contaminated products from food channels and make the food supply safer for the consumer.

Technical Abstract: Five, 2-kg test samples were taken from each of 120 farmers' stock peanut lots contaminated with aflatoxin. Kernels from each test sample were divided following USDA grade components: sound, mature kernels plus sound splits(SMKSS), other kernels (OK), loose shelled kernels (LSK), and damaged kernels (DAM). The kernel mass (g), aflatoxin mass (nanogram or ng), and aflatoxin concentration (ng of aflatoxin/g of peanuts) were measured for each of the 2,400 component samples. For the 120 lots tested, the average aflatoxin concentration among SMKSS, OK, LSK, and DAM components was 235, 2543, 11175, and 69775 ng/g, respectively. Cumulatively, the three aflatoxin risk components (OK, LSK, and DAM) accounted for 93.1 percent of the total aflatoxin, but only 18.4 percent of the test sample mass. Correlation analysis suggests the best predictor of the lot aflatoxin concentration is the cumulative aflatoxin mass (ng) in the three risk components OK+LSK+DAM (correlation coefficient, r=0.996). If the aflatoxi in the combined OK+LSK+DAM component is expressed in concentration units (ng/g), the correlation coefficient decreases to r=0.939. Linear regression equations relating aflatoxin in OK+LSK+DAM to the lot aflatoxin concentration were developed. The cumulative aflatoxin in the OK+LSK+DAM peanuts was not found to be an accurate predictor (r=0.539) of the aflatoxin in the SMKSS component. Three additional data sets published previously by co-authors were also statistically analyzed, and similar results were obtained by all data sets.

Last Modified: 10/20/2014
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