Multi-Mycotoxin Occurrence and Health Risk Assessment in Early Post-Harvest Durum Wheat, Barley, and Maize from Tunisia

Abstract

The contamination of cereals by mycotoxins represents a major concern due to their harmful effects on human health and food quality. The current study investigated the occurrence of major mycotoxins (AFB1, AFB2, AFG1, AFG2, OTA, ENA, ENA1, ENB, and ENB1) in 158 raw cereal samples (durum wheat, barley, and maize) collected from two Tunisian regions: Beja (continental region) and Mahdia (coastal region). Mycotoxins were extracted using the QuEChERS method and quantified by UHPLC–MS/MS. Several mycotoxins were detected at high levels across all the cereals. In the Beja region, durum wheat was contaminated with AFB1, AFG1, ENA, ENA1, ENB, and ENB1, with ENB being the most frequent (70%). Mahdia durum wheat was contaminated only with ENA, ENA1, ENB, and ENB1, with ENB1 being the most prevalent (22.6%). Barley from both regions was contaminated only with ENs. The ENB was the most frequent (Beja 66%, Mahdia 28.6%). Maize from Beja was contaminated by OTA and ENs, with ENA1 being the most frequent (22.5%), while maize from Mahdia was contaminated by AFB1, AFB2, AFG2, and ENs (AFB1 was the most frequent, 35%). All wheat samples contaminated with AFG1 (6.55%) exceeded the European Union maximum limit for AFs in cereals (4 µg/kg). Similarly, maize samples contaminated with AFB1 (17.5%), AFB2 (10%), and AFG2 (2.5%) exceeded the EU maximum limit for aflatoxins in maize (10 µg/kg). Additionally, maize samples contaminated with OTA (5%) exceeded the EU maximum limit for OTA in unprocessed cereals (5 µg/kg). The co-occurrence of multiple mycotoxins was observed in all cereal types, with up to six different mycotoxins detected in a single sample. Dietary risk assessment revealed high EDIs of AFB1, AFG1, and ENs through the consumption of wheat and barley by Tunisian adults. The calculated MOE values for AFB1 and AFG1 in wheat were below 10,000 (MOE = 1190 for AFB1 and 2.5 for AFG1), suggesting a potential health concern associated with dietary exposure. Despite this potential risk, AFB1 and AFG1 were detected in only 3% and 7% of the analyzed samples, respectively. These results highlight the need for regular monitoring and the establishment of regulations to control mycotoxins in Tunisian cereals.