Climate change and dietary health risks: aflatoxin contamination in Iberian maize

Background

Climate change is altering the ecology of mycotoxin-producing fungi and may increase food safety threats with implications for human health. The presence of aflatoxin B1 (AFB1) in maize is a cause for concern, as maize is used in food and feed chains and thus potentially affects human and animal health. This study assessed whether climate trends have changed the probability of AFB1 contamination in maize across the Iberian Peninsula under warming scenarios.

Methods

The AFLA-maize model was adapted to estimate climatic suitability for AFB1 contamination using high-resolution daily meteorological data from Copernicus ERA5 for 1980-2023. Temperature, relative humidity and precipitation were integrated into a bioclimatic aflatoxin index. Spatial and temporal analyses identified trends, variability and persistent hotspots. Scenario analyses estimated the effect of uniform warming increments of + 2 °C and +5 °C.

Results

Between 1980 and 2023, the Iberian Peninsula experienced an estimated mean temperature increase of approximately 1.3 °C. Over the same period, the probability of AFB1 contamination in maize increased by about 0.5-0.6 percentage points per decade, reaching 18% in 2023. Risk was amplified during very hot and dry years. Higher probabilities were consistently observed in the southern and interior regions, revealing an emerging climatic risk gradient associated with heat stress and aridity. Warming scenarios indicated further increases: +2 °C increased contamination probability across most regions, while +5 °C led to a marked non-linear escalation.

Conclusions

Climate change is already increasing the climatic suitability for AFB1 contamination in Iberian maize, with potential consequences for Public Health. Climate-informed surveillance, early warning systems and targeted sampling in high-risk regions and hot-dry years should be integrated into One Health and environmental health policies to strengthen public health preparedness.

Key messages

• Climate change is increasing the probability of aflatoxin B1 contamination in Iberian maize.

• Climate-informed surveillance can strengthen food safety, environmental health and One Health preparedness.