Occurrence of mycotoxins in farm-stored wheat in Ethiopia

Abstract

In recent years, food safety has become an integral component of ensuring food security. Mycotoxin development in staple cereals is a principal threat to realizing food safety in developing countries. With the objective to investigate incidences and levels of mycotoxins in farm-stored wheat from major growing districts of Ethiopia, a study was conducted based on 179 samples collected from six districts: Wenberma, Merawi, Ofla, Hetosa, Gedeb, and Lemo. Total aflatoxins (AFT), Ochratoxin A (OTA), total fumonisins (FUM), and deoxynivalenol (DON) were determined using lateral flow immunoassays. Results indicated that the most common method used by farmers forstoring wheat was polypropylene bag (92.2%, n=179). Incidences of AFT, OTA, FUM, and DON were 60.3%, 20.1%, 16.2%, and 9.5%, respectively. Levels in positive samples ranged from 2.5 μg/kg to 16.7 μg/kg for AFT, 2.1 μg/kg to 148.8 μg/kg for OTA, 0.33 mg/kg to 0.71 mg/kg for FUM, and 0.35 mg/kg to 1.14 mg/kg for DON. Age of wheat grains after harvest had a significant effect (P < 0.05) on the incidence of AFT. Less AFT incidence was observed in samples aged 3 months than in the older ones. None of the wheat samples exceeded the 20 μg/kg maximum level set for AFT by the FDA of the USA. However, 50.8% (n=179) exceeded the EU maximum level set at 4 μg/kg for AFT in cereals. Ochratoxin A (OTA) levels in 4.5% (n=179) of wheat samples exceeded the 5 μg/kg maximum level set by the EU for unprocessed cereals. Deoxynivalenol levels in 3.4% (n=179) of wheat samples exceeded the 0.75 mg/kg maximum level set by the EU. Besides, co-occurrences of mycotoxins were observed, and the binary co-occurrences of AFT-OTA (7.8%, n=179) and AFT-FUM (7.3%, n=179) were the dominant ones. The result of the present investigation underscores the occurrence of mycotoxins in farm-stored wheat in Ethiopia. Appropriate measures needto be taken to enable farmers to use improved grain storage technologies such as the use of multi-layer hermetic bags, which are capable of protecting wheat from physical and biological factors that lead to mycotoxin formation.