Food, feed, and the future
A growing challenge for farmers

Toxigenic fungi contaminate our major cereal crops with a range of harmful mycotoxins, which threaten human and livestock health¹.

Despite monitoring systems used to prevent acute exposure, Aspergillus and Fusarium mycotoxins still threaten food and animal feed security².

Additionally, changing climates and their influence on mycotoxins pose an increasing risk to the safety of our food and feed cereal industry^3,4.

Quick Facts!

• ⇰ Aspergillus y Fusarium contaminate our major cereal crops with an array of harmful mycotoxins.
• ⇰ Despite best efforts to protect our crops, it is estimated that 60-80% of crops are contaminated with mycotoxins.
• ⇰ Mycotoxins cause significant economic costs through the associated impacts on crop yields, animal productivity, and international trade⁵.

What are MYCOTOXINS and where do they come from?

Mycotoxins are toxic compounds naturally produced by fungi and pose a threat to human and animal health even at low concentrations^1,6.

There are approximately 300–400 known mycotoxins, with some of the most concerning being produced by Aspergillus and Fusarium species¹.

⇰ These fungi produce mycotoxins such as aflatoxins, deoxynivalenol, fumonisins, T-2 and HT-2 toxins, and zearalenone^7,8.

Aspergillus flavus and Aspergillus parasiticus are opportunistic pathogens of cereals both in the field and during crop storage.

⇰ Their most notorious products are aflatoxins (AF), which are classified as Class I human carcinogens^9,10.

Fusarium species are common in soils and infect crops in the field.

⇰ Fusarium head blight (FHB) is regarded as one of the most devastating fungal diseases in cereals and produces mycotoxins, such as deoxynivalenol (DON), nivalenol (NIV), T-2 and HT-2 toxins, zearalenone (ZEN) and fumonisins (FUM)⁸.

Health impacts

Mycotoxin contamination is widespread, with a significant percentage of crops exceeding safety limits. This is of particular concern due to the human health impacts these mycotoxins can cause⁴.

FUSARIUM

Fusarium species produce mycotoxins, such as DON and ZEN, that significantly reduce crop yields and pose health risks^11-14.

Deoxynivalenol (DON) disrupts protein synthesis, immune responses, and induces apoptosis¹⁵.

Its adverse effects on mammalian health cause symptoms such as vomiting, reduced appetite, stunted growth, and developmental delays¹⁶.

DON is not static, as it transforms into DON-3-β-d-glucoside (DON-3G) within cereals.

DON-3G appears less harmful, but gut bacteria can reverse this transformation, resurrecting the threat¹⁷. This ‘masked’ mycotoxin may secretly contribute to an increased total dietary mycotoxin burden.

ASPERGILLUS

The most notorious products associated with Aspergillus are aflatoxins, which are classified as Class I human carcinogens^9,10.

Aflatoxins contribute to cancer but also cause digestive issues and reproductive problems.

Aflatoxin B₁ (AFB₁) leads to weight loss, weakened immune responses, growth impairments, and even hepatocellular carcinoma or liver cancer¹⁸.

Mammals convert digested AFB₁ into AFM₁ that is excreted in their milk.

The consumption of AFM1-contaminated milk also poses health risks, including stunted infant growth and increased susceptibility to infectious diseases¹⁹. Outbreaks can disrupt the entire milk supply chain^4,20.

Economic impacts

Both Aspergillus and Fusarium species can infect cereal crops in the field, inhibiting crop development, affecting grain production, and resulting in yield losses^{3,4,14,21,22,23}.

Regulatory bodies, such as the EU Commission, establish legal thresholds to mitigate these risks²⁴.

• ⇰ Mycotoxin limits depend on their entry into food or feed supply chains and the intended consumer.
• ⇰ 2 μg of aflatoxin/kg and 750 μg of DON/kg are permitted for direct human consumption.
• ⇰ 20 μg of aflatoxin/kg and 8000 μg of DON/kg are allowed in animal feed^20,21.

However, this downgrading of contaminated cereals from food-to-feed reduces profit for the growers.

Outright crop rejection also results in greater profit losses and causes additional costs associated with hazardous waste disposal²⁵.

Aspergillus and Fusarium mycotoxins cost € billions

Recent findings bring to light the substantial economic impact of only two mycotoxins, aflatoxins and DON, on cereal farming.

Between the years 2010 and 2019, approximately 75 million tonnes of wheat (5% of wheat for human consumption) exceeded the limit for DON. This resulted in a financial loss of €3 billion due to downgrading to animal feed³.

Similarly, aflatoxins also caused downgrading of wheat destined to human consumption by 4.2% with an estimated additional €2.5 billion in losses⁴.

Figure 1. Contamination levels of food grains differ by grain for DON and aflatoxins. High levels of aflatoxin and DON contamination of food and feed cereals show that maize is of most concern⁴.

 

Figure 2. Summary of the environmental influence on Aspergillus and Fusarium^3,4.

Climate Change and MYCOTOXINS

Aflatoxins are predicted to become a major food safety issue in maize, especially in countries where a rise in temperature, together with increased CO₂ levels, and droughts are predicted to occur³⁶.

The optimum growth and mycotoxin production conditions show F. graminearum favoured by warm wet and A. flavus hot dry environments³⁰.

Climatic events, such as in northern Italy, have already been seen throughout the last decade in maize-growing regions prior to aflatoxin outbreaks³⁷.

Environmental changes threaten to increase the intensity and spread of mycotoxin contamination in Europe.

This issue requires efforts in the surveillance and control of mycotoxigenic fungal pathogens, to mitigate the risks they pose to sustainable safe cereal production.

What are the future challenges?

Co-contamination raises pressing questions about the health implications of low level exposure to multiple mycotoxins.

Johns (2022) found that in European wheat 25% of food and 45% of feed wheat containing DON tested positive for multiple FHB mycotoxins³.

Mycotoxins can undergo partial detoxification within their host plants or animals, resulting in the formation of ‘masked mycotoxins’.

These masked variants are challenging to detect and their presence in cereals introduces diverse economic and health impacts throughout our food and feed supply chains³⁸.

Regional barriers that have prevented disease spread in the past (topography, distance, climate) are being removed. Climate change, altered agronomic practices, and increased global transportation, have made it possible for fungal pathogens to enter new regions.

Why test for pathogens that have never been recorded in an area before? Favourable conditions are expanding geographically. For example, some Fusarium species such as F. verticillioides, are expanding their range to higher latitudes in Europe due to warming climates and increased maize cultivation in those regions. This expansion adds to the complexity of FHB management, as regions previously unaffected may now face heightened risks3.

Why is keeping an eye on these MYCOTOXIN threats challenging?

Traditional testing systems may not be effective in identifying masked mycotoxins or other Fusarium/Aspergillus mycotoxins. Using more sensitive and accurate detection techniques is imperative to assess the true extent of mycotoxin contamination³⁸.

Changing agricultural practices influence the likelihood of outbreaks. For instance, increased use of minimum tillage farming, agricultural composting, and the cultivation of maize, can provide an accessible home for Aspergillus and Fusarium to sporulate and to overwinter, increasing disease pressure and the risk of mycotoxin contaminations³⁹.

Infections can occur at various stages of crop growth, from seedling to post-harvest storage. What frequency of contamination is realistic and affordable to growers to maintain healthy safe crops?

Mycotoxin monitoring systems do not provide knowledge of the changing pathogen populations, impeding our ability to understand what is driving outbreaks or increased threat levels.

Global data on mycotoxigenic fungi and crop contamination is patchy. This hinders the improvement of holistic approaches to understand and mitigate their impact. The absence of data is not an absence of a mycotoxin threat.

Conclusions

Toxigenic fungi, such as Aspergillus and Fusarium species, contaminate cereal crops with harmful mycotoxins, posing a threat to human and animal health.

Mycotoxin contamination is widespread, with a significant percentage of crops exceeding safety limits.

Despite efforts to prevent crop diseases, aflatoxins and deoxynivalenol still contaminate cereals, affecting food and animal feed security.

More research into improved testing is required to understand the risk from masked mycotoxins and co-contaminants.

Changing environments can increase the risk of cereal infection and mycotoxin contamination. Leading to increased economic costs and health issues.

Co-ordinated research, industry, and governance efforts are needed to forecast and mitigate the growing mycotoxin threats.

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