Sampling and analytical variability associated with determination of aflatoxin and ochratoxin A in capsular ginger powder sold as a dietary supplement

Authors: TRUCKSESS, M - FDA; Whitaker, Thomas; WEAVER, C - FDA; SLATE, A - NC STATE UNIVERSITY; GIESBRECHT, F - NC STATE UNIVERSTIY; RADER, J - FDA; BETZ, J - NIH

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2008
Publication Date: 3/15/2009
Citation: Trucksess, M.W., Whitaker, T.B., Weaver, C.M., Slate, A.B., Giesbrecht, F.J., Rader, J.I., Betz, J.M. 2009. Sampling and analytical variability associated with determination of aflatoxin and ochratoxin A in capsular ginger powder sold as a dietary supplement. Journal of Agricultural and Food Chemistry 57:321-325.

Interpretive Summary: Products processed from ginger roots are widely used for digestive problems and dietary supplements. In general they are safe for consumption but may contain contaminants such as mycotoxins that are detrimental to health. The toxicological effects of long-term low-level exposure to carcinogenic toxins such as the aflatoxins and ochratoxin A are largely unknown. As a result, the U.S. Food and Drug Administration has established regulatory guidelines for maximum levels for mycotoxins such as the aflatoxins and ochratoxin A that are allowable in human foods. In order to accurately estimate the true level of a mycotoxin in dietary supplements made from ginger roots, proper sampling techniques must be developed. Because of the random variability among sample test results, it is difficult to determine the true mycotoxin level in bulk lots of ginger and lots exceeding the maximum level may be accepted into the market. Studies were developed to measure the variability among replicated sample test results when sampling the same bulk lot. The total variability associated with the mycotoxin test procedure was partitioned into sampling and analytical variability components. Knowing the variability associated with sampling and analysis, sampling plans can be designed to minimize the number of lots exceeding the maximum level which will provide the consumer with a safer food supply.

Technical Abstract: Safety of botanicals is of primary concern to the consumers of medicinal plants and dietary supplements. In the United States, the Food and Drug Administration generally recognize ginger as safe. Ginger roots could be contaminated with mycotoxins, which are toxins produced by molds during production and/or storage conditions. Mycotoxins such as the aflatoxins (AF) and ochratoxin A (OTA) have shown adverse effects to human and animal health. In order to assess the contamination levels of these mycotoxins in ginger, the development of a mycotoxin testing procedure is needed. A mycotoxin test procedure usually composed of sampling, sample preparation and analytical steps. Since ginger is finely comminuted, there is no sample preparation step in our study and we focused only on sampling and analytical variability associated with determination of AF and OTA in ginger capsules. Three lots of ginger sold as a powder in capsules form and packaged in individual bottles were analyzed for both AF and OTA. The total variability associated with measuring aflatoxin and OTA in powdered ginger was partitioned into bottle-to-bottle, within bottle, and analytical variances. The variances were estimated using a nested design. For both aflatoxin and OTA, the within bottle variance associated with the 5 g test sample size was the largest component of variability accounting for about 50 and 84% of the total variance, respectively; the analytical variance accounted for about 25 and 8% of the total variability, respectively; and the bottle-to-bottle variance accounted for about 25 and 8% of the total variance, respectively.