Aflatoxin M1 in Milk and Aflatoxin B1 in Animal Feed in Bangladesh: A Systematic Review, Meta-Analysis and Literature-Based Dietary Risk Assessment.

BACKGROUND

Aflatoxin M1 (AFM1), the carcinogenic metabolite of aflatoxin B1 (AFB1), passes into the milk of animals fed mould-contaminated feed. Bangladeshi feed and milk surveillance have developed separately, and integrated dietary-risk estimates are scarce.

OBJECTIVE AND

DESIGN

To pool AFM1 occurrence in Bangladeshi milk, summarise feed AFB1 and characterise age-stratified dietary risk. The assessment is literature-based and modular: no Bangladeshi study reports paired feed and milk data, so compartments are joined by parameter transfer.

METHODS

Prevalences were pooled by DerSimonian-Laird random-effects models with prediction intervals, subgroup, meta-regression, leave-one-out and small-study analyses. Exposure was modelled deterministically and probabilistically (100,000 iterations), with uncertainty tabulated following EFSA guidance.

RESULTS

Across 20 datasets (N = 605), pooled prevalence was 58.7% (95% CI 51.6%-65.5%; I2 = 61.9%; 95% prediction interval 32.1%-81.1%). Heterogeneity was structured by region (p = 0.001), not milk type (p = 0.980). The sample-weighted mean was 143 ng L-1 (geometric mean 92); 83% of milk exceeded the EU maximum level. Reconstruction from feed AFB1 predicted 24-282 ng L-1, containing 18 of 20 dataset means. Margins of exposure were 95 (infants) and 175 (toddlers), with probabilistic medians 157 and 286; the deterministic hazard index exceeded unity in every age group, the probabilistic median in every group except adults.

CONCLUSIONS

Infant and child margins of exposure remain far below the 10,000 benchmark under every scenario and robustness check. The estimate is screening-level, resting on transferred parameters and ELISA-based measurement. Monsoon-aware feed management, enforcement of the national milk standard and paired feed-milk surveillance are indicated.