Fungal species and multi-mycotoxin in bread wheat (Triticum aestivum L.) in Ethiopia

Abstract

Ethiopia is sub-Saharan Africa’s greatest wheat producer. However, its production, productivity and utilisations are constrained by fungal infections, which lead to yield losses and mycotoxin contaminations. The present study was aimed to determined fungal species and multi-mycotoxins in wheat grain samples (n=178) collected during the 2020 cropping season in Ethiopia. Different fungal genera of Alternaria, Aspergillus, Fusarium, Penicillium, and Rhizopus species were isolated from the infected grain samples, of which Fusarium species were abundantly prevalent. Multi-mycotoxin analysis done using liquid chromatography-tandem mass spectrometric (LC-MS/MS). Overall, 49 metabolites of different fungal species including masked, regulated and emerging mycotoxins were detected and categorised into eight groups. Among major mycotoxins and derivatives, deoxynivalenol was frequently detected in about 70.8% of samples with the maximum concertation 15,900 μg/kg, followed by its masked metabolites of deoxynivalenol-3-glucoside detected in 64% of the samples with maximum level 2,120 μg/kg. Among Fusarium metabolites, 15-hydroxyculmorin was detected in 46.6% of wheat samples with maximum level of 4,290 μg/kg, while chrysogin, enniatin B and culmorin were detected in 58.4, 43.3 and 44.9%, of the wheat samples with maximum levels of 154, 325 and 2,860 μg/kg, respectively. Among Alternaria metabolites tenuazonic acid was most prevalent mycotoxin occurring in 79.2% of samples with maximum level (236 μg/kg). Furthermore, metabolites from other fungal genera were detected at different levels. The widespread presence and high amount of multi-mycotoxin in wheat samples indicated proportionately higher exposure levels, which could result in serious food safety and health consequences. Integrating several management strategies both before and after harvest may lower the risk of mycotoxin contamination in wheat, being used as diversified food products in the country.