Evaluation of aflatoxin B1 (AFB1) contamination levels in corn and corn-growing soils from the leading corn-producing districts of Sri Lanka

Aim: Mycotoxins are the third most dangerous food contaminants, with one billion metric tons of food being contaminated annually. This study was conducted as a comprehensive assessment of aflatoxin B1 (AFB1) contamination in corn kernels and corn-growing soils across the six main corn-producing districts of Sri Lanka. Methods: A total of 12 soil samples were collected from the front, middle, and rear regions of each field from the subsurface and at various depths. In addition, six healthy corn kernel samples were harvested from the same locations. AFB1 was detected using enzyme-linked immunosorbent assay (ELISA). To verify the accuracy and precision of the assay, a recovery evaluation was conducted. To assess the distribution and correlations of AFB1 concentration in maize, its growing soil, and other environmental parameters, a comprehensive statistical study was conducted. Results: AFB1 level patterns implied that environmental factors influence the variability across the six districts. The temperature significantly affected AFB1 contamination in corn kernels with a p-value of 0.00014 (p < 0.05). Corn AFB1 levels showed a significant correlation with AFB1 levels in corn growing soils, with a p-value of 0.0261 (p < 0.05). Moreover, maximum AFB1 contamination was recorded at temperatures ranging from 26°C to 30°C. Conclusions: This study reveals a concerning trend; most of the corn samples from these districts exceeded the regulatory AFB1 levels set by the United States Food and Drug Administration (US FDA), and a significant positive correlation of corn AFB1 with soil AFB1 highlights soil as a potential reservoir for AFB1-producing fungi. Moreover, linking environmental elements to AFB1 data might encourage adaptive management strategies, which may help reduce contamination.