Mycotoxin exposure through the consumption of processed cereal food for children (< 5 years old) from rural households of Oshana, a region of Namibia

Abstract

Mycotoxin exposure from contaminated food is a significant global health issue, particularly among vulnerable children. Given limited data on mycotoxin exposure among Namibian children, this study investigated mycotoxin types and levels in foods, evaluated dietary mycotoxin exposure from processed cereal foods in children under age five from rural households in Oshana region, Namibia. Mycotoxins in cereal-based food samples (n = 162) (mahangu flour (n = 35), sorghum flour (n = 13), mahangu thin/thick porridge (n = 54), oshikundu (n = 56), and omungome (n = 4)) were determined by liquid chromatography-tandem mass spectrometry. Aflatoxin B₁ (AFB₁, 35.8%), zearalenone (27.2%), fumonisin B₁ (FB₁, 24.1%), citrinin (CIT, 12.4%) and deoxynivalenol (10.5%) were the major mycotoxins quantified. Food samples (35.8% (n = 58) and 6.2% (n = 10)) exceeded the 0.1 µg/kg AFB₁ and 200 µg/kg FB₁ EU limit for children's food, respectively. Several emerging mycotoxins including the neurotoxic 3-nitropropionic acid, moniliformin (MON), and tenuazonic acid were quantified in over 50% of all samples. Co-occurrence of AFB₁, CIT, and FB₁ detected in 4.9% (n = 8) samples, which could heighten food safety concerns. Regarding exposure assessment and risk characterization, average probable dietary intake for AFB₁ from all ready-to-eat-foods was 0.036 µg/kg bw/day, which resulted in margin of exposures (MOE) of 11 and 0.65 risk cancer cases/year/100,000 people, indicating a risk of chronic aflatoxicosis. High tolerable daily intake values for FB₁, and MOE for beauvericin and MON exceeded reference values. Consumption of a diversified diet and interventions including timely planting and harvesting, best grain storage, and other standard postharvest food handling practices are needed to mitigate mycotoxin exposure through contaminated cereal foods and to safeguard the health of the rural children in Namibia.

Keywords: 3-Nitropropionic acid; Aflatoxin; Margin of exposure; Mycotoxin exposure; Processed cereal food; Risk assessment.

Fig. 1

Co-occurrence of mycotoxins in cereal food samples