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

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 Sao Paulo, Brazil. The validation showed an adequate linearity (R-2 = 0.999). and limits of detection and quantification of 1.13 and 3.59 mu g.kg(-1), respectively. Recovery rates of 104, 102, and 107% at the concentrations of 4, 10, and 20 mu g.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 B-1 was present in concentrations ranging from 1.13 to 29.2 mu g.kg(-1), with only two samples (3.3%) exceeding the maximum allowed limit of 20 mu g.kg(-1). The ic-ELISA developed here is an accessible tool for the rapid monitoring of aflatoxin contamination in the peanut production chain.