Sampling plans for the determination of aflatoxin B1 in large shipments ofanimal feedstuffs

Incremental samples (50, 100, and 500 g) were systematically collected from large shipments of copra meal pellets, copra cake, and palm kernel cake to study the distribution of aflatoxin B-1 and evaluate adherence of distribu tion to the model, CVis2 (EQ) = A + B/M-is (where CVis = coefficient of var iation of the true concentration of aflatoxin B-1 within the incremental sa mples; M-is = mass of the incremental samples; and A and B are constants), Also evaluated was the distribution of aflatoxin B-1 among 1 kg composite s amples, produced both by random combination of existing incremental samples and by collection of 1 kg composite samples (composed of 10 x 100 g increm ents) from additional batches of copra meal pellets and cottonseed cake. Th e efficiency of selected sample preparation (grinding and subdivision) proc edures was compared, culminating in the development and description of a va riety of sampling plans, The coefficient of variation (CV) among incrementa l samples varied from 0 to 38%, and was independent of incremental sample s ize, No significant difference (F-test, 5% significance level) was found be tween the efficacy of 4 sample preparation methods when these methods were applied to the commodities described above, Various sampling plans were eva luated with estimated CVs from 4.0 to 12.5%, for the aflatoxin B-1 content of the composite samples.