Testing shelled corn for aflatoxin, Part I: estimation of variance components.

Area of Science:

• Agricultural Science
• Food Safety
• Analytical Chemistry

Background:

• Aflatoxins are toxic secondary metabolites produced by certain fungi, posing significant health risks in food commodities.
• Accurate quantification of aflatoxins in shelled corn is crucial for regulatory compliance and consumer protection.
• Variability in testing procedures can impact the reliability of aflatoxin measurements.

Purpose of the Study:

• To investigate and quantify the sources of variability in testing shelled corn for aflatoxin contamination.
• To develop mathematical models to predict testing variance based on aflatoxin concentration and testing parameters.
• To partition the total variance into sampling, sample preparation, and analytical components.

Main Methods:

• Tested eighteen lots of shelled corn for aflatoxin contamination.
• Estimated and partitioned total variance into sampling, sample preparation, and analytical variances.
• Utilized regression analysis to model the relationship between aflatoxin concentration and different variance components.

Main Results:

• All variance components (total, sampling, sample preparation, analytical) increased with higher aflatoxin concentrations.
• Developed mathematical expressions to model these relationships, enabling variance estimation for various testing parameters.
• For a sample with 20 ppb aflatoxin, sampling variance constituted 77.8% of the total variance.

Conclusions:

• Sampling is the predominant source of variability in shelled corn aflatoxin testing, especially at higher concentrations.
• The developed models can guide the optimization of sample size, subsample size, and analytical methods for improved accuracy.
• Understanding and controlling variance sources are essential for reliable aflatoxin testing in agricultural products.