Evaluation of laboratory performance with aflatoxin methods by means of the AOCS Smalley Check Sample Program

The American Oil Chemists' Society Smalley Check Sample Program offers ongoing check sample series for determination of aflatoxins in peanut meal, cottonseed meal, and corn meal. Laboratories participating in this program represent a worldwide cross section of industry, regulatory, and commercial laboratories. Each annual series presently consists of 7 samples including a solution of an unknown mixture of aflatoxins B1, B2, G1, and G2 for direct spotting and quantitation. Participant analyses of the solution of aflatoxins resulted in coefficients of variation generally higher than those of any sample. Comparison of 4 years of results for analysts using BF and CB methods of analysis for peanut meal samples with aflatoxin B1 levels ranging from 2 to 56 ng/g resulted in higher aflatoxin B1 results for the CB method. The number of participants reporting results by HPLC methods is small; however, their results compare closely with those using TLC methods.