Submitted to: Journal of Association of Official Analytical Chemists International
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/6/2005
Publication Date: 9/1/2006
Citation: Ozay, G., Seyhan, F., Yilmaz, A., Whitaker, T.B., Slate, A. 2006. Sampling hazelnuts for aflatoxin, part i: uncertainty associated with sampling, sample prepatation, and alalysis. Journal of Association of Official Analytical Chemists International 90:1028-1035. Interpretive Summary: Aflatoxin is a carcinogenic and toxic compound produced by molds found in several agricultural commodities such as peanuts, cereals, and treenuts. Regulatory agencies world wide such as the U. S. Food and Drug Administration have established a maximum limit for aflatoxin in various foods as a method to reduce aflatoxin contamination in the food supply. Hazelnuts, along with other tree nuts, are inspected by exporters, importers, processors, and food manufacturers to detect and remove contaminated lots from the food chain. It is difficult to determine aflatoxin levels of large shipments or lots because of the errors associated with sampling, sample preparation, and analysis, collectively called the aflatoxin test procedure. Errors associated with the aflatoxin test procedure results in some lots being mis-classified. Some of the good lots test bad and some of the bad lots test good. The errors associated with measuring aflatoxin in hazelnuts was determined. Once the magnitude of the testing errors are know, methods can be developed to reduce the testing errors which will reduce the number of lots mis-classified. This will reduce both health risks to the consumer and economic loss to importers, processors, and food manufacturers.
Technical Abstract: The variability associated with the aflatoxin test procedure used to estimate aflatoxin levels in bulk shipments of hazelnuts was investigated. Sixteen 10 kg samples of shelled hazelnuts were taken from each of twenty lots were suspected of aflatoxin contamination. The total variance associated with testing shelled hazelnuts was estimated and partitioned into sampling, sample preparation and analytical variance components. Each variance component increased as aflatoxin concentration (either B1 or total) increased. With the use of regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific aflatoxin concentration. The sampling, sample preparation, and analytical variances associated with estimating aflatoxin in a hazelnut lot at 10 ng/g total aflatoxin using a 10 kg sample, 50 g subsample, dry comminution with a Robot Coupe mill, and HPLC analytical method are 174.40, 0.74, and 0.27, respectively. The sampling, sample preparation, and analytical steps of the aflatoxin test procedure accounted for 99.53%, 0.38% and 0.09% of the total variability, respectively.