Evaluation of reduction of aflatoxins by near infrared spectrometric sorting in the highly aflatoxin-contaminated peanut lots

Abstract

Peanuts are one of the most susceptible crops to aflatoxigenic fungi, such as Aspergillus flavus and Aspergillus parasiticus, and is often contaminated with aflatoxins (AFs). AF contamination of peanuts is a major human and animal health hazard that has an economic impact worldwide. Numerous control and management strategies have been developed to reduce the levels of AFs in peanuts and sorting is the final stage in the process targeted at decreasing AF levels. Previous studies have shown that handpicking and electric color sorting are not entirely effective in reducing AF levels because of the occurrence of apparently healthy but internally moldy kernels with high AF levels. A previous study (Hirano, et al. 1998) showed that near infrared (NIR), the ratio of transmittance energies at two wavelengths of 700 to 1100, was applicable for efficiently removing internally moldy kernels. However the use of this procedure was limited to a sample that contained artificially inoculated kernels and low levels of AFs. This present study evaluated the performance of spectrometric sorting in naturally and highly AF-contaminated peanut lots on a commercial scale. The NIR spectrometric sorting clearly showed that AFs could be effectively decreased to levels of < 10 μg/kg even when the lot was highly contaminated with > 700 μg/kg of AFs by rejecting deteriorated kennels, including those that were internally moldy.