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.

An indirect competitive immunoassay (ic-ELISA) was developed using monoclonal antibody produced by hybridoma AF4, which showed high specificity and reactivity with aflatoxin B1 (AFB1) and aflatoxicol, but low cross-reactivity to other analogs. This low cost reliable method was applied for AFB1 monitoring in the poultry chain of a high agribusiness potential region (northern Paraná state, Brazil). Maize, laying hens feed and egg samples were collected from two poultry farms (with production above 200,000 eggs/day) and evaluated by intralaboratory validated ic-ELISA. The sensitivity of such a validated assay, detecting picogram levels of aflatoxins, demonstrated to be proper for surveying daily ingested cumulative toxins and estimating risks. Additionally, more than 61.00% of positive egg samples ranged between the limit of quantification (LOQ – 0.035 ng/g) and 1.00 ng/g, values commonly not covered by commercial kits. Positive data (>LOQ) occurred in 22 maize (56.40%), 34 feed (85.00%) and 192 (48.00%) egg samples. Mean contamination in maize was 1.51±0.94 ng/g (range 0.11-3.91 ng/g), 1.26±0.96 ng/g in feed (0.10-3.58 ng/g), and 1.01±0.77 ng/g in egg (0.05-3.85 ng/g). No statistical difference was observed between farms (P>0.05) for any of the matrices analysed. However, the difference between median values in maize (0.98 ng/g – Farm A; 1.76 ng/g – Farm B) indicated a higher contamination trend in farm B, possibly due to inadequate local storage. Although there is no limit stipulated for AFB1 contamination in eggs, the levels detected in samples were low and do not represent an immediate risk to animal production or human consumption. Nevertheless, the high frequency of positive maize and feed samples in this field of agribusiness should be highlighted. Sensitive aflatoxin monitoring procedures must be strategically carried out from raw materials to animal derived products, aiming harmless production, which also assures human health.