Reduction of aflatoxins by near-infrared spectrometric sorting in the aflatoxin-contaminated almond lots

Abstract

  Almonds are nutritious and have become popular confectionary ingredients. A significant concern in the almond industry is product loss caused by aflatoxin (AF) contamination infected by the toxigenic fungi such Aspergillus flavus. AF contamination of almonds is a major human health risk concern and has an economic impact on the almond industry worldwide. Our previous report showed that near-infrared (NIR) spectrometric sorting of peanuts effectively decreased the levels of AFs by rejecting deteriorated kennels even when the lot was highly contaminated. In this study, we used NIR sorting to reduce the AF levels in the contaminated almonds. The transmittance ratio at 800-1100 nm (800/1100 nm) can be used to remove deteriorated kernels, including AF-contaminated kernels. The ratio could not directly detect AF-contaminated kernels but detected the internal discoloration caused by fungal digestion in the kernels, similar to sorting peanuts. In this study, twelve sub-samples (approximately 550 kg), including relatively low and high levels of AF-contaminated samples (maximum 117 μg/kg of AFs, in total), were segregated by the spectrometric sorting. After sorting, none of the acceptable categories contained detectable amounts of AFs. NIR spectrometric sorting can reduce health concerns and economic losses, enhance the efficient utilization and reconditioning of AF-contaminated lots in the almond industry, and help attain the sustainable development goals (SDGs).