*4.5. Fumonisin*

To date, only the fumonisins FB1 and FB2 appear to be toxicologically significant. The occurrence of FB1 in cereals, primarily maize, has been associated with serious outbreaks of leukoencephalomalacia (LEM) in horses and pulmonary oedema in pigs. However, *F. proliferatum* appears as a source of fumonisins in wheat grain, and fumonisins might, at very low levels (in the ppb range), be frequently present in wheat [60]. Fumonisins have been reported to cause diseases in humans and animals after consumption of contaminated food and feed, especially esophageal cancer [61]. In the current research, the concentrations of fumonisin B1 and B2 were in accordance with other studies where the natural occurrence of fumonisin B1 (FB1) ranged from 15–155 μg/kg, fumonisin B2 (FB2) ranged from 12–86 μg/kg, and fumonisin B3 (FB3) ranged from 13–64 μg/kg [62]. In other research, concentrations of FB1 were higher, ranging from 958 to 4906 μg/kg [63].

### *4.6. Zearalenone (ZEN), Moniliformin (MON), and Beauvericin (BEA)*

*F. graminearum* is among the main species producing ZEN in Bulgarian wheat where more than half of the samples tested were contaminated with ZEN [64]. In the current research, we used a strain of *F. gramienarum,* so it was expected that higher concentrations of ZEN would occur in the inoculated samples, but as confirmed in previous research, *F. graminearum* prefers lower temperatures for the production of ZEN [65].

Moniliformin (MON) had higher concentrations in inoculated samples of Ficko than in durum wheat, which contained 45.1 μg kg−<sup>1</sup> of MON in the 2013/2014 season and 171.7 μg kg−<sup>1</sup> of MON in the 2012/2013 season [66].

In the current research, only one sample contained beauvericin (BEA) in trace amounts. Opposite to that in previous Italian research, BEA was detected (0.64 to 3.5 μg/g) in all investigated samples [59]. Also, BEA was detected at concentrations <10 μg/kg in field samples from Norway and Finland [19]. Although MON and BEA were not produced by the *Fusarium* species tested, they occurred in small amounts due to natural infection by other *Fusarium* species in the field.
