Assessment of Grain Handling, Consumption and Risk of Exposure to Aflatoxins Among Adolescents in Secondary Schools Using Urinary Aflatoxin M1 Biomarker

Aflatoxin contamination poses a significant public health concern, particularly in low-resource settings where dietary habits and food handling practices increase exposure risks to vulnerable populations. This study examined grain handling, consumption and the risk of exposure to aflatoxin among secondary school adolescents in Mvomero District, Morogoro-Tanzania. The study used a descriptive cross-sectional design employing stratified multistage proportionate sampling to obtain 396 secondary school adolescents and a non-probability, purposive sampling to obtain 33 teachers responsible for school meals from 33 schools. Data were collected using surveys, food frequency questionnaires and 24-hour dietary recalls. Urinary Aflatoxin M1 (AFM1) was analyzed using Enzyme-Linked Immunosorbent Assay (ELISA). The study was conducted across secondary schools in Mvomero district in Morogoro region of Tanzania, between February and May 2024. The findings revealed high aflatoxin exposure among secondary school adolescents in Mvomero District, Tanzania, with a median urinary AFM1 level of 0.035 ng/mL (IQR = 0.07 ng/mL), exceeding the hepatocellular cancer risk threshold of 0.0036 ng/mL. Higher AFM1 concentrations were significantly associated with the consumption of aflatoxin-susceptible grains (p < .05) and were notably higher in younger adolescents (0.039 ng/mL) than older ones (0.024 ng/mL; p = .04). Poor grain handling practices contributed to this exposure, as 96.9% of schools stored grains in non-protective polypropylene bags. Additionally, meals lacked diversity with 93.8% of schools relying mainly on maize and all using beans. Although a national school feeding guideline exists, none of the schools have begun its implementation, indicating a lack of enforcement. These results underscore the dual influence of diet and age on aflatoxin exposure and call for urgent interventions, including improved grain storage, enhanced public awareness, dietary diversification, and enforcement of school feeding policies to mitigate health risks in this vulnerable population.