Introduction
Climate change, described as a “climate emergency” or “climate crisis,” represents a threat to food safety on a global scale, according to the Emerging Risks Unit of the European Food Safety Authority (EFSA). In this context, the Intergovernmental Panel on Climate Change (IPCC) reports that global temperatures could rise by up to 4.8 °C by the year 2100. Consequently, climate change is associated with a shifting pattern of mycotoxin contamination in grain and cereal crops, such as wheat or maize. This is a key aspect to consider in ensuring food safety within the agricultural industry, highlighting the importance of applying good agricultural practices and maintaining adequate storage conditions (Magan et al., 2011).
The mycotoxin challenge:
Mycotoxins are highly toxic substances produced by fungi, predominantly from the genera Aspergillus, Fusarium, and Penicillium, which infect crops and food products. The synthesis of mycotoxins is strongly influenced by environmental conditions, with humidity and temperature being the most critical factors (Torres et al., 2019).
In this context, mycotoxins are considered a risk factor for food safety on a global scale due to:
- Their frequent occurrence in major food and feed products.
- Their high chemical stability during food and feed processing.
- Their adverse effects on animal and human health.
The challenge of climate change:
Climate change is a global issue that has a severe impact on the agricultural sector. Owing to greenhouse gas emissions generated by human activity, changes are being observed in temperature, humidity, and the distribution of precipitation, leading to an increased frequency of extreme events such as floods and droughts. While these environmental changes differ across scenarios and regions, Table 1 outlines the main variables involved.
| Climate variables | Affected regions |
|---|---|
| Increase of 2.5-5 °C, with extended drought periods | Southern, Central, Western, and Atlantic Europe |
| Increase in total precipitation | High-latitude regions; tropical regions; and, in winter, mid-latitude northern regions |
| Decrease in total precipitation | Southern Europe and Northern Africa; Central Europe; North America, Central America, and South America; Northeastern Brazil; and Southern Africa |
| Decrease in mean annual soil moisture | Mediterranean region and subtropical areas |
| Increase in mean annual soil moisture | Eastern Africa; Central Asia; and regions with higher precipitation |
Table 1. Climate variables and affected regions (Liu et al., 2021).
The observed changes in climate variable patterns directly affect crop development, fungal infection, and mycotoxin production.
What is the relationship between climate change and mycotoxins?
It is expected that the impact of climate change will increase the occurrence of mycotoxins in animal feed and human food.
Although the effects of climate change vary by geographic region, the predicted increases in rainfall and temperature in some areas may create more favourable conditions for the proliferation of Fusarium in Europe. Conversely, more frequent and prolonged drought periods may stimulate the production of aflatoxins by Aspergillus flavus, both before and after harvest (Medina et al., 2014).
Predictive models can be mechanistic or empirical and are based on climate patterns, including temperature, precipitation, and relative humidity. Various quantitative models have been reported in the literature to predict the incidence of mycotoxins during the pre-harvest phase of crops, depending on climate change scenarios or long-term climate data from different regions (Table 2).
These studies have mainly focused on mycotoxins produced by fungi of the genus Fusarium, such as deoxynivalenol (DON) and zearalenone (ZEA) in wheat and rice, and aflatoxins (AFs) in maize (Liu et al., 2021):
| Model | Information provided | Information obtained | Crop | Mycotoxin | Region |
|---|---|---|---|---|---|
| Madgwick et al. (2011) | • Temperature • Precipitation | Percentage of plants affected by Fusarium Head Blight (FHB) | Wheat | – | United Kingdom |
| Van der Fels-Klerx et al. (2012) | • Temperature • Precipitation • Relative humidity • Flowering date • Maturity date | DON concentration at harvest | Wheat | DON | Northwestern Europe |
| Joo et al. (2019) | • Temperature and relative humidity at flowering • Temperature at harvest • Region • Rice variety | ZEN concentration in rice at harvest | Rice | ZEN | South Korea |
| Chauhan et al. (2008) | • Temperature • Radiation • Precipitation • Water and nitrogen levels in soil • Yield | AFs risk index | Maize | AFs | Australia |
| Battilani et al. (2016) | • Temperature • Relative humidity • Precipitation • Leaf moisture • Water activity • Flowering and harvest dates | Cumulative index of AFs | Maize and wheat | AFs | Europe |
| Van der Fels-Klerx et al. (2016) | • Temperature • Precipitation • Relative humidity • Wind speed • Flowering and harvest dates • Feed composition | Concentration of aflatoxin B1 (AFB1) in harvested crops and aflatoxin M1 (AFM1) in milk | Maize | AFs (AFB1, AFM1) | Eastern Europe |
Table 2. Information provided and obtained from different predictive models (Liu et al., 2021).
The results reported by these predictive models indicate an increased occurrence of mycotoxins in grains and cereals due to changes in environmental conditions (Liu et al., 2021).
Preventive strategies
Various strategies can be implemented to apply good agricultural practices before harvest, aiming to prevent or minimise mycotoxin production in crops:
- Select a grain variety with a flowering schedule appropriate for the cultivation region.
- Choose a grain variety with greater resistance to infection by mycotoxigenic fungi.
- Consider the predictions of mycotoxin incidence models. If the models forecast extremely high contamination in the future, it may be advisable to introduce more resistant alternative crops in that area.
Therefore, mycotoxins have a significant and unpredictable impact on the agri-food industry, making the analysis of raw materials, feed, and food products a critical control point to safeguard the food chain, including the end consumer. In particular, this monitoring is essential in animal production, as it not only predicts risk but also informs strategies to mitigate the adverse effects of these toxins on animal health and performance.
Conclusion
The analysis of climate change scenarios is a valuable tool for understanding regional differences in mycotoxin occurrence, driven by variations in environmental conditions across different crops. Future efforts should focus on developing predictive models to guide adaptation to climate change and ensure that mycotoxin levels in food remain below recommended limits, thereby protecting the health of animals and humans.
