Evaluation and mitigation of mycotoxin contamination across the Scottish cereal supply chain to assess human exposure and inform risk analysis
Project Lead
Challenges
Chemical food contaminants are a persistent problem when assuring the provision of safe and healthy foods for consumers. Cereals are frequently contaminated with mycotoxins produced by a fungal infection of grains in the field or storage. Guidance on good agricultural practices to minimize risks of Fusarium fungi and mycotoxins in UK wheat is available. As demand for high-quality UK food oats increases, guidance for growers to improve agronomy practices has also been developed. Prevention of Fusarium fungi and mycotoxins is, to date, not included in such advice.
Once a cereal is contaminated, mycotoxins are subject to further plant metabolism, resulting in conjugated metabolites, so-called masked mycotoxins, which co-occur in cereal grains. Masked mycotoxins are not toxic per se, but the human gut microbiota releases free mycotoxins in the colon, which will contribute to exposure.
The fate of some Fusarium mycotoxins, such as deoxynivalenol and its masked form deoxynivalenol-glucoside, has been well described in humans and validated urinary biomarkers are available to assess exposure. However, accurate assessments of dietary exposure to potent mycotoxins T-2 and HT-2 toxins in humans are very limited. Our preliminary work has shown that increased oat consumption resulted in increased urinary excretion of T2 and HT2, and there is an urgent need to better understand the absorption of T2 and HT2 and their masked forms from food and their metabolism in humans to fully validate urinary biomarkers to be used in human biomonitoring studies.
Overall, the production of T2 and HT2 and their masked forms in oat cereals, their fate through processing and their contribution to overall exposure in humans are not well understood.
Questions
- What are the sources and epidemiology of foodborne disease in Scotland and what interventions can be introduced to reduce foodborne disease?
- What new methods can be developed to assist with identifying and tackling emerging microbiological, chemical, and nutrient risks in food for Scottish consumers and businesses?
Solutions
This project aims to minimize the risk to consumers from mycotoxin contamination in cereal foods by improving our understanding of the sources of contamination in primary cereal production and processing and by assessing human exposure and risk through biomarker analysis.
Understanding contamination within the cereal industry and supporting testing
We are improving our understanding of contamination within the cereal industry and testing common, commercially available tests for a range of type A trichothecenes and their masked forms in cereals. Several commercial tests are available for the determination of regulated mycotoxins in cereals. However, these methods are validated for specific free mycotoxins and their ability to detect masked forms is less well described especially for type A trichothecenes.
Identifying key intervention points to prevent and minimise mycotoxin contamination in the cereal supply chain
Much research has been conducted to identify the main drivers of fungal growth and mycotoxin production in agricultural systems with the main focus on Aspergillus fungi in maize and Fusarium fungi in wheat. These studies have identified a range of drivers from climate parameters to varietal differences and agronomy practices that are increasing the risk for fungal infection and mycotoxin contamination. However, less attention has been given to the oat supply chain and the production of mycotoxins and masked mycotoxins in oat cereals. The oat crops have already been identified to be at risk of mycotoxin contamination. This project focuses on identifying key intervention points in oat production and processing to minimise contamination.
Inform risk assessment of human mycotoxin exposure through oat foods
Urinary biomonitoring is an important tool to assess dietary exposure to mycotoxins in consumers. Validated biomarkers exist for some mycotoxins, but the fate of type A trichothecenes and their masked forms in the human body is not well understood. We are predicting the bioaccessibility of mycotoxins from oat foods and confirming the findings in a human diet intervention to fully validate urinary biomarkers.
Project Partners
Progress
Understanding contamination within the cereal industry and supporting testing
Within industry settings, rapid tests for mycotoxins are a key component of the assessment of grain quality. Such rapid tests are designed to indicate the presence of important Fusarium mycotoxins including T2/HT2, DON and ZEN. However, these methods are validated for specific free mycotoxins and their ability to detect masked forms is less well described.
Hence we liaised with key industry stakeholders representing the wheat, oat and barley sectors in the UK, and identified two rapid test platforms used by 98% of industry respondents. We found both platforms to perform well with acceptable recoveries of the free Fusarium mycotoxins all cereal matrices. However, cross-reactivity to masked mycotoxins was found to be substantial for one platform and this cross-reactivity could lead to substantial overestimation of free mycotoxin levels in cereals. This is relevant as current legislative limits only include free mycotoxins and not masked forms and key findings have been communicated to industry and policy stakeholders.
Identifying intervention points to prevent and reduce mycotoxin contamination in the oat supply chain
This project investigates key agronomy practices as mitigation strategies to prevent the production of free and masked mycotoxins in Scottish oats in collaboration with the cereal industry, the Scottish Organic Producers Association (SOPA) and Scotland’s Rural College (SRUC).
In a farm survey we analysed oat samples from 33 farms across Scotland and collected additional sample information via questionnaire. The study shows that low cereal intensity within a crop rotation can reduce the risk for high levels of T2 and HT2 toxins, the most commonly detected Fusarium mycotoxins in oats. We also found organic oats to contain lower levels of these mycotoxins compared to conventional oats.
In field trials run at SRUC’s Aberdeenshire Cropping Experimental Platform we analysed oat samples from 4 years (2017-2020) and confirmed that organic oats contained lower levels of T2, HT2 and their masked forms than conventional oats grown in the same location.
Industry impact
To support growers our work has identified two potential solutions to mitigate the mycotoxin risk in oat crops: low cereal intensity within a crop rotation and organic production. These can be implemented at farm level and offer practical solutions for growers.
To support processors our work has evaluated rapid test kits and found cross-reactivity with masked mycotoxins which will better inform decision making on site during cereal processing.
Policy impact
Evidence from this study has been submitted to the Food Standards Agency to inform their ongoing risk analysis for T2/HT2 toxins in cereals. This process will assess the risk of consumer exposure to these important mycotoxins and will inform any future risk management policy.
Case Study
Publications and other outputs
Free and Modified Mycotoxins in Organic and Conventional Oats (Avena Sativa L.) Grown in Scotland (2023) – paper published in Toxins 15(4), 247 by Daud N, Currie V, Duncan G, Filipe JAN, Yoshinari T, Stoddart G, Roberts D, Gratz SW
A talk entitled: Mycotoxin contamination in Scottish oats and potential mitigation strategies for growers and processors was presented at Crop Production in Northern Britain (Dundee, February 2024).
A talk entitled: Potential mitigation strategies for free and modified Fusarium mycotoxins in oats was presented at the 14th World Mycotoxin Forum, session Managing and Mitigating Mycotoxin (Antwerp, Belgium, October 2023).
Related Projects
The current crisis in public health (obesity, diabetes, cardiovascular disease, stroke and some cancers) is strongly rooted in an imbalance in dietary components. A healthy balanced diet not only requires reductions in fat, salt, sugar, and in overall calorie intake, but also an increase in fibre and an appropriate level of protein intake. The aim of this RD is to strengthen our understanding...
- Food & Drink Improvements
- Diet & Food Safety
- Human Nutrition
- 2016-2022