Development of ic-Elisa for the screening of aflatoxin contamination in the peanut production chain

Abstract: The objective of this work was to standardize and validate an indirect competitive enzyme-linked immunosorbent assay (ic-Elisa), as a low-cost tool, to monitor the presence of aflatoxin in common and blanched peanuts (Arachis hypogaea) in the production chain. The presence of aflatoxin B1, moisture content, and water activity were analyzed in 60 samples of the peanut cultivar Runner IAC 886, from the 2014/2015 and 2015/2016 harvests of the region of Alta Paulista, in the state of São Paulo, Brazil. The validation showed an adequate linearity (R2 = 0.999), and limits of detection and quantification of 1.13 and 3.59 μg kg-1, respectively. Recovery rates of 104, 102, and 107% at the concentrations of 4, 10, and 20 μg kg-1 aflatoxin B1, respectively, were also recorded. The ic-Elisa showed a good reproducibility with a high-intraday precision, with 1.87% coefficient of variation (CV), and interday precision with 6.75% CV. The moisture content ranged from 4.0 to 7.2% (mean of 5.8%), and the water activity from 0.4848 to 0.6997 (mean of 0.5990) for the tested samples. Aflatoxin B1 was present in concentrations ranging from 1.13 to 29.2 μg kg-1, with only two samples (3.3%) exceeding the maximum allowed limit of 20 μg kg-1. The ic-ELISA developed here is an accessible tool for the rapid monitoring of aflatoxin contamination in the peanut production chain.摘要：本研究旨在标准化并验证一种间接竞争性酶联免疫吸附试验（indirect competitive enzyme-linked immunosorbent assay, ic-ELISA），将其作为低成本检测工具，用于监测生产链中普通花生与脱皮花生（Arachis hypogaea）内的黄曲霉毒素残留情况。本研究以巴西圣保罗州阿尔塔保利斯塔地区2014/2015及2015/2016季收获的Runner IAC 886品种花生共60份为研究对象，对其中黄曲霉毒素B1含量、水分含量及水分活度进行了检测。该方法验证结果显示，其具备良好的线性关系（决定系数R²=0.999），检出限与定量限分别为1.13 μg·kg⁻¹与3.59 μg·kg⁻¹。在黄曲霉毒素B1添加浓度为4、10、20 μg·kg⁻¹时，回收率分别达104%、102%与107%。ic-ELISA表现出优异的重复性：日内变异系数（CV）为1.87%，具有较高的日内精密度；日间变异系数为6.75%，具备良好的日间精密度。供试样品的水分含量介于4.0%至7.2%之间，平均值为5.8%；水分活度介于0.4848至0.6997之间，平均值为0.5990。黄曲霉毒素B1含量范围为1.13 μg·kg⁻¹至29.2 μg·kg⁻¹，仅2份样品（占比3.3%）超出法定最大允许限量20 μg·kg⁻¹。本研究开发的ic-ELISA是一款便捷易用的检测工具，可用于花生生产链中黄曲霉毒素污染的快速监测。