Sampling bulk consignments of dried figs for aflatoxin analysis

Abstract

The between-box aflatoxin distribution for a bulk consignment of whole dried figs (11 tons) has been established by the individual analysis of 200 boxes (analysed as single samples of 12 kg each of homogenized material) randomly selected from a total of 850 boxes. The within-box aflatoxin distribution for three boxes was investigated by the analysis of 12 subsamples in each case made up of packets of figs totalling 1 kg in weight. Of the 200 boxes, 134 contained less than 10 micrograms/kg total aflatoxins whereas the highest level found was 227 micrograms/kg. The highest level of aflatoxins found in a single 1 kg unit was 2063 micrograms/kg. The batch average aflatoxin contamination determined on the basis of a single 20 kg homogenized sample (20 x 1 kg subsamples) was 33 micrograms/kg, compared to a level of 15 micrograms/kg calculated as the average of 200 determinations. Evaluations are made of different possible ways of sampling and the confidence that can be associated with each of these is estimated.