Efficacy of Electronic Color Sorting and Hand Picking to Remove Aflatoxin Contaminated Kernels from Commercial Lots of Shelled Peanuts1

Abstract

Samples (200-lb) from 40 commercial lots of shelled peanuts which contained an average concentration of 48 parts-per-billion aflatoxin were sorted with an electronic color sorter 3 to 5 times and then hand picked in an attempt to remove discolored kernels which usually contain higher concentrations of aflatoxin than other kernels. Prediction equations indicated that cumulative removal of 2, 4, 6, 8 and 10% of the kernels from each sample by electronic sorting would remove an average of 16, 28, 37, 45 and 51% of the aflatoxin, respectively. Electronic sorting became less selective for aflatoxin-contaminated kernels during each additional sorting operation. Careful hand picking for discoloration was far more selective for aflatoxin-contaminated kernels than electronic color sorting. An average 72% of the aflatoxin was in kernels that were removed by electronic sorting and subsequent hand picking. The efficacy of aflatoxin removal with electronic sorting was highly variable among lots. This variability indicates that each lot should be pretested to determine if aflatoxin can be effectively removed before the expense of electronic color sorting is incurred.