First evidence on occurrence, and risk assessment of EU-regulated mycotoxins along the cassava value chain in Uganda

Abstract

This study investigated the occurrence and distribution of EU-regulated mycotoxins (aflatoxin B₁, B₂, G₁, G₂, fumonisins B₁, B₂, ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEN), and citrinin (CIT) in cassava products, as well as assess the potential risk of Aflatoxin B1 (AFB₁) exposure among cassava consumers. A total of 192 samples of cassava products (flour and chips) were analysed using LC/MS-MS. All positive samples irrespective of their origin(flour or chips), exhibited AFB₁ levels exceeding the EU regulatory threshold of 5 µg/kg. The sum of fumonisins-FB₁ + FB₂, ZEN and DON were significantly (P < 0.05) higher in cassava flour (14.3 µg/kg; 3.71 µg/kg; 25.1 µg/kg) compared to chips (6.54 µg/kg; 1.25 µg/kg; 0.25 µg/kg), respectively. Aflatoxins G₂ was not detected in all the 192 samples analysed. Cassava flour samples from farmers exhibited significantly (P < 0.05) higher mean concentrations of AFB₁ (27.1 µg/kg), total aflatoxins (78.2 µg/kg) and ochratoxin A (79.6 µg/kg) in contrast to wholesalers, whose mean levels were notably lower at 8.91, 5.79 µg/kg and 2.44 µg/kg, respectively, pointing the likely critical source of mycotoxin contamination. Cassava consumers in Northern Uganda are at a higher risk of 2.06 cancer cases per 100,000 individuals per year compared to those in Eastern Uganda at 0.25. This study underscores the urgent need for improving storage practices of cassava flour at the household level, especially in Northern Uganda, recognises a shift from the conventional practice of sampling in market areas to household-level samples, and emphasises the need for analytical methods that target more than one mycotoxin.