Dietary grain ingestion is the primary route of human exposure to the adverse effects of Cd; therefore, an understanding of the transfer characteristics of Cd in a system involving soil, grain, and humans is crucial for health risk alleviation and pollution control. In this study, Cd bioaccessibility and bioavailability for humans from grains of sweet maize (Zea mays convar. saccharata var. rugosa) cultivars grown on a contaminated field (1.05 mg Cd kg-1 soil) were assessed by combining a simulated in vitro digestion method with a Caco-2 cell model. Results showed that cultivars differed significantly in grain Cd concentration, bioaccessibility, and bioavailability with the corresponding values of 0.07 to 0.20 mg kg-1 DW (dry weight), 4.10 to 6.20%, and 0.01 to 0.04 µg g-1grain, respectively. The estimated daily intake of Cd through sweet maize grain was within the range of 0.04 and 0.25 μg kg-1 body weight, which is lower than the tolerable limit recommended by the Joint FAO/WHO Expert Committee on Food Additives (JEFCA). Conclusively, results from the present study indicate that most grain Cd remains non-bioaccessible and thus might not present adverse health effects in humans. Therefore, sweet maize cultivars could be used to produce healthy food crops in low-to-moderately Cd-contaminated soil.
Keywords: Bioaccessibility; Bioavailability; Cadmium; Estimated daily intake; Healthy grain; Sweet maize.
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