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Updated: Aug 6, 2026

Non-destructive SPE-UPLC-based Quantification of Aflatoxins and Stilbenoid Phytoalexins in Single Peanut (Arachis spp.) Seeds
Published on: April 19, 2024
Sampling almonds for aflatoxin, part I: estimation of uncertainty associated with sampling, sample preparation, and
Thomas B Whitaker1, Andrew B Slate, Merle Jacobs
1Agricultural Research Service, Department of Agriculture, Box 7625, North Carolina State University, Raleigh, NC 27695-7625, USA. Tom_Whitaker@ncsu.edu
Uncertainty in aflatoxin testing for almonds stems mainly from sampling, not sample preparation or analysis. Understanding these variance components helps improve accuracy in estimating aflatoxin levels in bulk nut lots.
Area of Science:
- Food Science
- Analytical Chemistry
- Agricultural Science
Background:
- Regulatory limits for aflatoxins in almonds and tree nuts are established globally.
- Accurate estimation of aflatoxin concentration in bulk lots is challenging due to uncertainties in testing procedures.
Purpose of the Study:
- To evaluate aflatoxin sampling plans by investigating uncertainty in sampling shelled almonds.
- To partition total variance into sampling, sample preparation, and analytical components.
Main Methods:
- Twenty lots of shelled almonds were sampled for aflatoxin contamination.
- Total variance for B1 and total aflatoxins was estimated and partitioned.
- Regression analysis was used to develop mathematical expressions relating variance components to aflatoxin concentration.
Main Results:
- All variance components (total, sampling, sample preparation, analytical) increased with aflatoxin concentration.
- Sampling variance constituted the largest portion (96.2%) of total variance.
- Mathematical models were developed to predict variance based on sample size, subsample size, and analysis count.
Conclusions:
- Sampling is the dominant source of uncertainty in aflatoxin testing of shelled almonds.
- The developed mathematical relationships can optimize testing protocols for improved accuracy.
- Variance estimates for B1 and total aflatoxins were consistent.
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