Submitted to: Official Methods of Analysis of AOAC International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2007
Publication Date: 9/15/2007
Citation: Whitaker, T.B., Saltsman, J.S., Ware, G.M., Slate, A.B. 2007. Evaluating the performance of sampling plans to detect hypoglycin A in ackee fruit shipments imported into the United States. Official Methods of Analysis of AOAC International 90:4. Interpretive Summary: Ackee, the national fruit of Jamaica, is used as a fresh food product in the Jamaican domestic market and is processed in cans for both the domestic and export markets. The unripe ackee fruit contains a naturally occurring toxic amino acid, called hypoglycin A (HGA), which is associated with an illness known as Jamaican vomiting disease that can be fatal. Because of the risk that unripe ackee fruit containing HGA may enter into the U.S., the Food and Drug Administration (FDA) placed an import ban on ackee fruit in 1973. Currently, the FDA is considering the modification of the import ban, which will require the development of a monitoring program to estimate the HGA concentration in lots imported into the U.S. One important aspect to any HGA monitoring program is the design of a sampling plan to estimate the HGA concentration in a bulk lot. Because of the uncertainty associated with sampling and analytical methods to estimate HGA in a large bulk lot, lots can be misclassified by a given sampling plan design. Studies were conducted to measure the uncertainty of sampling methods to estimate HGA in bulk ackee lots and develop an evaluation method to predict the percentage of lots tested that would be misclassified in a monitoring program. The evaluation method has been used by FDA to investigate the effects of regulatory limits and sample size on reducing lots misclassified in a monitoring program. The evaluation method will help FDA develop a cost effective monitoring program to reduce lots misclassified to acceptable levels and increase consumer safety.
Technical Abstract: Hypoglycin A (HGA) is a toxic amino acid that is naturally produced in unripe ackee fruit. In 1973 the FDA placed a worldwide import alert on ackee fruit, which banned the product from entering the U.S. The FDA has considered establishing a regulatory limit for HGA and lifting the ban, which will require a monitoring program to be developed. The establishment of a regulatory limit for HGA requires the development of a scientifically based sampling plan to detect HGA in ackee fruit imported into the United States. Thirty-three lots of ackee fruit were sampled according to an experimental protocol where 10 samples, i.e., ten 19-oz cans, were randomly taken from each lot and analyzed for HGA using liquid chromatography. The total variance was partitioned into sampling and analytical variance components, which were found to be a function of the HGA concentration. Regression equations were developed to predict the total, sampling, and analytical variances as a function of HGA concentration. The observed HGA distribution among the 10-HGA sample test results was compared to the normal and lognormal distributions. A computer model based upon the lognormal distribution was developed to predict the performance of sampling plan designs to detect HGA in ackee fruit shipments. The performance of several sampling plan designs was evaluated to demonstrate how to manipulate sample size and accept/reject limits to reduce misclassification of ackee fruit lots.