Occurrence of aflatoxin M₁ in human breast milk in Bangladesh

Breast milk is the best, most complete form of nutrition for newborns and infants. However, human milk can contain aflatoxin M₁ (AFM₁) upon ingestion of dietary mycotoxin contaminants, namely, aflatoxin B₁ (AFB₁), by lactating mothers. AFB₁ and its hydroxylated metabolite AFM₁ are potent carcinogens and thus an important issue in food safety and public health. This study is the first to explore the presence of AFM₁ in breast milk samples from Bangladesh and assess infant exposure to this toxin, as a consequence of maternal mycotoxin intake. A total of 62 breast milk samples were collected from nursing mothers in Sylhet region of Bangladesh. The milk samples were collected between October 2019 and March 2020 and analyzed by a sensitive enzyme-linked immunosorbent assay. AFM₁ was detected in 51.6% of the breast milk samples (colostrum, transitional and mature milk), with a mean concentration of 4.42 ± 0.56 pg/mL, and in the range between LOD (4.0 pg/mL) and 6.66 pg/mL. The frequent detection of AFM₁ in breast milk indicates widespread dietary exposure to mycotoxins in our cohort. The estimated average daily intake of AFM₁ for all nursed infants was 0.49 ng/kg b.w./day. No significant correlations were observed between AFM₁ levels in human milk and food items regularly consumed by nursing women. Overall, AFM₁ levels in breast milk samples from the Sylhet region of Bangladesh are moderate, and lower than the permissible levels established for AFM₁ in dairy milk or infant formulae (50 and 25 ng/kg, respectively). Yet, this first data for AFM₁ breast milk contaminant levels just reflect the recent situation in one cohort, and monitoring should be continued.