Abstract
Mycotoxin contamination is a global threat to food safety and human health, especially
in regions facing food insecurity, such as Sub-Saharan Africa. This intervention study
evaluates the effectiveness of nixtamalization, a traditional alkaline cooking method, in reducing
mycotoxin levels in maize and corresponding urinary biomarkers of exposure. Forty
adult healthy volunteers from an informal settlement in Kliptown, Soweto (South Africa),
were randomly assigned to consume control maize or visibly moldy maize subjected to
nixtamalization. Nixtamalization achieved a reduction in fumonisin B3 and deoxynivalenol
(DON) to unquantifiable or undetectable levels in maize, while reducing fumonisin B1
(FB1), fumonisin B2, and zearalenone (ZEN) by 95%, 95%, and 89%, respectively. Aflatoxin
B1 was unquantifiable before and eliminated after treatment. Biomarker analysis revealed
that after consumption of either control or nixtamalized maize, urinary levels of FB1, ZEN,
and its metabolites α- and β-zearalenol (α- and β-ZEL) did not show significant differences
between groups (p > 0.05). DON and tenuazonic acid levels were not affected by the
intervention (p > 0.05), with urinary detection frequencies remaining above 90%. These
results demonstrate nixtamalization effectively lowers mycotoxin levels in maize, resulting
in exposure levels comparable to control maize, and highlight human biomonitoring as a
sensitive tool for evaluating food safety interventions.