Project Number: 6645-44000-009-00
Project Type: Appropriated

Start Date: Dec 21, 2004
End Date: Nov 30, 2009

Objective:
Objective 1 - Develop sampling plans that minimize buyers' risk (bad lots accepted) and sellers' risk (good lots rejected) when detecting quality attributes in agricultural commodities. Sampling plans will be developed to detect the following attributes in foods: aflatoxin in almonds, genetically modified (GM) proteins in grains, peanut proteins (allergens) in foods, foreign material (FM) in shelled peanuts, and TCK spores in wheat. Objective 2 - Determine the percentage of total aflatoxin in farmers' stock peanuts that is partitioned into each milled peanut category (jumbo, medium, number one, splits, oil stock, loose shelled kernels, and discolored or damaged kernels) during the shelling process. Objective 3 - Develop sampling plans for biosecurity purposes that maximize the chance of detecting various food matrices intentionally adulterated with biological and/or chemical agents.

Approach:
Objective 1 - Experiments are designed to obtain variability and distributional data to construct operating characteristic (OC) curves which can be used to predict the performance of sampling plan designs to detect specific quality attributes in a food matrix. From the OC curve, the false positives (sellers' risk or good lots rejected) and false negatives (buyers' risk or bad lots accepted) for specific sampling plan can be determined. Objective 2 - Forty 50-kg samples of farmers' stock (FS) peanuts, contaminated with varying levels of aflatoxin, will each be processed in an USDA, ARS pilot shelling plant. Each 50-kg sample will be divided into loose-shelled kernels (LSK) and in-shell peanuts. The in-shell peanuts will be shelled and the shelled kernels will be sized into five commercial peanut grades, jumbo, medium, number ones, splits, and oil stock. Shelled kernels in each grade will be color sorted into accepts and rejects components for a total of 10 categories (5 size grades x 2 accept/reject components). The LSK will also be sized in a like manner into the same five commercial grades and color sorted into accept/reject components or 10 categories. After the peanuts in each of the 20 categories are weighed, the aflatoxin in each of the 20 categories will be measured. From the weights and aflatoxin values in each category, a mass balance can be used to compute aflatoxin in all kernels before sorting by size and color. Then, the percentage of total aflatoxin in the FS peanuts before shelling, sizing, and color sorting that is partitioned into each of the 20 categories will be determined. Objective 3 -The development of mathematical models requires the measurement of chemical or biological agents among replicate samples taken from contaminated lots, from which variability and distributional characteristics provide the basis for development of statistical models and prediction of validity, reliability, and feasibility (false positives and false negatives) associated with various sample plan designs.