Distribution of Aflatoxin in Pistachios. 3. Distribution in Pistachio
Process Streams
SchatzkiThomas F.
PanJames L.
1996
The distribution of aflatoxin concentration has been measured by
sampling 19 process streams
ranging from 1 to 1000 nuts/sample. The 19 streams comprise
substantially the entire sorted product
of one producer for crop year 1992. Similar results were obtained
by another producer for 1993.
The fraction of total aflatoxin accounted for by each process
stream was computed. It was concluded
that 90% of aflatoxin is contained in 4.6% of (low-quality) product;
removal of this product would
reduce average aflatoxin from 1.2 to 0.12 ng/g for all product sold for
human consumption. On the
basis of the aflatoxin distributions of the processed as well as an
unprocessed stream, the conclusion
is drawn that all aflatoxin found here arises in the orchard; none is
produced under normal processing
conditions. It is estimated that the necessary sample size (in
terms of the sample mean and desired
variance of the mean) for aflatoxin measurement in pistachios is given
by number of nuts = (8 ×
10<sup>5</sup> ng/g) × mean/variance.
Keywords: Processing; tree nuts; removal; process control; sampling; growth
model; aflatoxin
analysis