Malting of Fusarium Head Blight-Infected Rye (Secale cereale): Growth of Fusarium graminearum, Trichothecene Production, and the Impact on Malt Quality

Abstract

This project was initiated with the goal of investigating the malt quality of winter rye cultivars and hybrids grown in the United States in 2014 and 2015, but high levels of deoxynivalenol (DON) were subsequently found in many of the malt samples. DON levels in 75% of the investigated rye samples (n = 117) were actually below 1.0 mg/kg, as quantified by a gas chromatography combined with electron capture detector (GC-ECD). However, 83% of the samples had DON in excess of 1.0 mg/kg following malting, and the average DON level in malted rye was 10.6 mg/kg. In addition, relatively high levels of 3-acetate DON (3-ADON), 15-acetate DON (15-ADON), nivalenol (NIV), and DON-3-glucoside (D3G) were observed in some rye malts. Our results show that rye grain DON is likely a poor predicator of type B trichothecenes in malt in practice, because high levels of malt DON, 15-ADONm and D3G were produced, even when the rye samples with DON levels below 0.50 mg/kg were processed. Fusarium Tri5 DNA content in rye was highly associated with malt DON levels (r = 0.83) in a small subset of samples (n = 55). The impact of Fusarium infection on malt quality was demonstrated by the significant correlations between malt DON levels and wort viscosity, β-glucan content, wort color, wort p-coumaric acid content, and total phenolic content. Additional correlations of rye Fusarium Tri5 DNA contents with malt diastatic power (DP), wort free amino nitrogen (FAN) content, and arabinoxylan content were observed.

Selected Trichothecenes in Barley Malt and Beer from Poland and an Assessment of Dietary Risks Associated with their Consumption

“…If mycelia are visible, they recommend the analysis of the grain for mycotoxins. There are some indications in the literature [32][33][34][35] that high amounts of additional mycotoxins may be synthesized in fungi-contaminated grain during the malting process, thus significantly impacting food safety.…”

Relevant Fusarium Mycotoxins in Malt and Beer

“…Later, Leslie and Summerell (2007) [ 33 ], in their “The Fusarium laboratory manual”, describe F. thapsinus , F. proliferatum , F. andiyazi and F. pseudonygamai as the most important species isolated from millet from all the cultivation regions. Rye and oats are also susceptible to FHB, which, similar to the case of the previously mentioned cereals, is mainly driven by F. graminearum and less frequently by F. culmorum , F. avenaceum and F. poae [ 70 , 71 ]. During the 2004 Symposium on Buckwheat, Kalinova, Voženilkova and Moudry (2004) [ 72 ] reported F. tricinctum and F. avenaceum being isolated from the surface of buckwheat kernels between 1999 and 2000, among other bacteria.…”

Implications of Mycotoxins in Food Safety

“…In another study conducted in India, the analyzed oat samples were contaminated with ZE in the proportion of 84%, identifying values between 5.31 and 389 μg/kg [80]. In the US study by Jin et al, 75% of the rye samples were contaminated with DON, reporting values below 1.0 mg/kg, but showed an increase through the malting process [106].…”