Presence of zearalenone and trichothecene mycotoxins in Fusarium-infected New Zealand grown wheat

Fusarium species fungal infection occurred widely in the 1986 Manawatu and Waikato wheat harvest. A significant amount of grain was rejected because of this infection, commonly indicated by reddish or purplish discolourations. Fusarium species are known to produce several types of toxic secondary metabolites, and these have caused major problems to cereal producers and consumers throughout the world. Many Fusarium species produce the oestrogenic compound Zearalenone as well as toxic trichothecenes such as nivalenol (NIV), deoxynivalenol (DON), 1.5 acetyl-deoxynivalenol, T-2 toxin, HT-2 toxin and diacetoxyscirpenol. All of these toxins have been reported in naturally contaminated samples. We analysed 12 samples of reject wheat for some known Fusarium mycotoxins. Zearalenone levels ranged from 0.04 to 0.35 mg/kg with only four samples exceeding 0.15 mg/kg. These four samples were analysed further for trichothecenes and had concentration of NIV 0.02-0.77 mg/kg and DON 1.510.8 mg/kg. Significant concentrations of an as-yet unidentified compound believed to be a new trichothecene mycotoxin were also observed. The concentrations of zearalenone are well within overseas guidelines (l-5 mg/kg) for sows, the most sensitive animals, and would not preclude using the grain for feeds. A maximum concentration of…