HT-2 and T-2 toxins in Norwegian oat grains related to weather conditions at different growth stages

Anne-Grete Roer Hjelkrem,Einar C Strand,Torfinn Torp,Ruth Dill-Macky,Heidi Udnes Aamot,Ingerd Skow Hofgaard,Guro Brodal,Simon G Edwards

doi:10.1007/s10658-017-1394-3

Anne-Grete Roer Hjelkrem, Einar C Strand + Show 6 more

Open Access

https://doi.org/10.1007/s10658-017-1394-3

Copy DOI

Abstract

High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2 + T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2 + T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2 + T2 in oat grains. Our data show that adequate predictions of the risk of HT2 + T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2 + T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2 + T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2 + T2 accumulation in oat grains. Our data indicated that HT2 + T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.

Highlights

High concentrations of HT-2 toxin (HT2) and T-2 toxin (T2), primarily produced by Fusarium langsethiae (Edwards et al 2012; Torp and Nirenberg 2004; Torp and Langseth 1999), are occasionally detected in Norwegian oat grains (Norwegian Scientific Committee for Food Safety 2013)
Among the 188 samples included in the dataset, the amount of HT2 + T2 detected varied from a maximum of 2998 μg kg−1 to the levels of detection (LOD)
Nine percent of the samples contained HT2 + T2 levels above the indicative limit set for unprocessed oats (1000 μg kg−1), and 25% of the samples contained HT2 + T2 values higher than our more rigorous level of 500 μg kg−1 used in this study

Summary

Introduction

High concentrations of HT-2 toxin (HT2) and T-2 toxin (T2), primarily produced by Fusarium langsethiae (Edwards et al 2012; Torp and Nirenberg 2004; Torp and Langseth 1999), are occasionally detected in Norwegian oat grains (Norwegian Scientific Committee for Food Safety 2013). As the documentation on the occurrence of HT2 and T2 (HT2 + T2) toxins is still scarce, the European Commission (2013) has only set indicative levels for the sum of HT2 + T2 in cereals and cereal products. These levels are not feed or food safety levels, when concentrations are detected above these levels investigations should examine the factors leading to the presence of HT2 + T2 toxins. By identifying the main variables that influence mycotoxin accumulation and their interactions, a better understanding of the accumulation of these mycotoxins will be achieved and a prediction model can be developed

Objectives

Methods

Results

Discussion

Conclusion