BACKGROUND: Infants are a vulnerable population whose nutrition changes as complementary foods are introduced; a process which may modify patterns of exposure to dietary mycotoxins. However, exposure monitoring of dietary mycotoxin mixtures in several biological samples obtained from breastfed and non-exclusively breastfed children is scarce. OBJECTIVES: To examine mycotoxin co-exposure patterns in infants using a multi-specimen, multi-mycotoxin approach. METHODS: Breast milk, complementary food and urine obtained from 65 infants, aged 1-18 months, in Ogun state, Nigeria, were analyzed for mycotoxins using ultra-sensitive LC-MS/MS approaches. RESULTS: Complementary food was contaminated with seven distinct classes of mycotoxins including aflatoxins (9/42 samples; range: 1.0-16.2ug/kg) and fumonisins (14/42; range: 8-167ug/kg). Aflatoxin M1 was detected in breast milk (4/22), while six other classes of mycotoxins were quantified; including dihydrocitrinone (6/22; range: 14.0-59.7ng/L) and sterigmatocystin (1/22; 1.2ng/L) detected for the first time. Mycotoxins were detected in 64/65 of the urine samples, with seven distinct classes of mycotoxins observed demonstrating ubiquitous exposure. Two aflatoxin metabolites (AFM1 and AFQ1) and FB1 were detected in 6/65, 44/65 and 17/65 samples, respectively. Mixtures of mycotoxin classes were common, including 14/42, 22/22 and 56/65 samples having 2-4, 2-6 or 2-6 mycotoxins present, for complementary food, breast milk and urine, respectively. Aflatoxin and/or fumonisin was detected in 12/14, 4/22 and 46/56 for complimentary foods, breast milk and urine, respectively. Furthermore, the detection frequency, mean concentrations and occurrence of mixtures were typically greater in urine of non-exclusively breastfed compared to breastfed children. CONCLUSIONS: The study provides novel insights into mycotoxin co-exposures in children in a mycotoxin high-risk country without proper food safety measures. Albeit a small sample set, it highlights significant transition to higher levels of infant mycotoxin exposure as complementary foods are introduced, providing impetus to mitigate during this critical early-life period and encourage breastfeeding.

Cereals and cassava-based foods serve as major dietary sources for several households in Nigeria. However, these foods are highly prone to contamination by moulds and aflatoxins owing to poor storage and vending practices. We therefore studied the fungal diversity of maize, cassava-based flour (pupuru) and rice vended in markets from Ondo state, Nigeria, and assessed the aflatoxin levels of these using Enzyme-Linked Immunosorbent Assay. Fungi were detected in 93 (88 %) of the 106 food samples. Molecular analysis of 65 representative isolates revealed 26 species belonging to 5 genera: Aspergillus (80.9 %), Penicillium (15.4 %) and Talaromyces (1.9 %) in the Ascomycota; Syncephalastrum (1.2 %) and Lichtheimia (0.6%) in Mucoromycota. Aspergillus flavus was the predominant species in the food samples. Aflatoxins were found in 98 % of the 42 representative food samples and about one half (49.8 %) exceeded the 10 μg/kg threshold adopted in Nigeria for total aflatoxins. Integrated mitigation options, including at post-harvest stages, are suggested to ensure consumer safety.