Food safety remains a critical global challenge, with contaminated food contributing substantially to disease burden and economic losses worldwide (Altomare et al., 2021; Wu et al., 2014). According to the world health organization (WHO), it is estimated that 600 million, nearly one in 12 people worldwide, are exposed to contaminated food and suffer from foodborne illnesses annually, underscoring the importance of identifying and mitigating risks across the food supply chain, with approximately 420,000 deaths each year (WHO, 2024).
       
Among food contaminants, natural toxins-particularly mycotoxins-pose a significant and persistent threat to human health and animal production systems. Mycotoxins are estimated to contaminate a substantial share of global food crops, with some estimates suggesting that up to 25% of the world’s crops may be affected (Eskola et al., 2019; Topi et al., 2021). These toxic secondary metabolites are produced by filamentous fungi, commonly in the genera Aspergillus, Fusarium and Penicillium. Among these, aflatoxins are considered the most hazardous due to their potent carcinogenic, hepatotoxic and immunosuppressive effects. Aflatoxin B1 (AFB1), in particular, has been classified as a Group 1 carcinogen by the International agency for research on cancer, with strong epidemiological evidence linking exposure to hepatocellular carcinoma. These toxins frequently contaminate staple crops such as maize (Zea mays L.), posing serious risks to food security, public health and international trade (Munkvold et al., 2019).
       
Aflatoxin contamination is strongly influenced by environmental conditions, particularly temperature and moisture. Optimal growth of A. flavus, the primary aflatoxin-producing species, occurs under warm and moderately humid conditions, while toxin production is significantly enhanced at temperatures above 33°C. Consequently, climate change-characterized by rising temperatures, altered precipitation patterns and increased frequency of extreme weather events-has emerged as a key driver of aflatoxin risk worldwide (Cotty and Jaime-Garcia, 2007; Medina et al., 2014).
       
In Southern Europe, including the Balkan Peninsula, recent decades have seen accelerated warming trends that outpace global averages, linked to notable aflatoxin contamination events in maize during extreme heat and drought years such as 2003, 2012 and 2015. Countries such as Croatia, Serbia, Romania and Albania have experienced significant outbreaks, underscoring vulnerability to climate-driven mycotoxin risks (Kos et al., 2018; Topi et al., 2023; Topi et al., 2024). Studies highlight the role of climate change in spreading aflatoxin B1-producing molds from tropical regions to the Mediterranean and Central Europe (Baranyi et al., 2015; Battilani et al., 2016). Data from Albania, including high AFB1 levels in corn (0.32-3550 μg/kg in 2014-2015) and recent research showing mycotoxigenic fungi and AFB1 in corn and wheat (Mato et al., 2024a), reveal increasing mycotoxin risks. Albanian cereal surveys also document Fusarium mycotoxins, minor unregulated Aspergillus and Penicillium toxins and wheat quality issues related to food safety, emphasizing the diverse and growing mycotoxin challenges in Albanian agriculture (Topi et al., 2021; Topi et al., 2024).
       
Climate change will affect animal production and, consequently, global food security (Kuraz et al., 2021; Manjeet et al., 2023). Mycotoxin-producing fungi are common components of the epiphytic and endophytic microflora of crops, resulting in natural contamination of crops in the field and during storage (Chukwudi et al., 2021). The most hazardous mycotoxins in human foods and animal feeds include aflatoxins, ochratoxins, fumonisins, deoxynivalenol and zearalenone, which pose a serious health hazard (EFSA, 2020). Mycotoxins enter the food chain through preharvest and postharvest fungal infections. Among these, aflatoxin B (AFB1) is the most toxic and is classified as a carcinogen (Mitchell et al., 2016) -epidemiological data link AFB1 to liver cancer in humans (Liu and Wu, 2010). Food laws establish maximum allowable levels of contaminants, including aflatoxins (Regulation (EU) 2023/915 on certain contaminants in food. The development of aflatoxigenic molds and the production of AF depend on the type of substrate or crop where they grow (Abrar et al., 2013). AFB1 ingested by dairy animals is metabolized and excreted in milk as aflatoxin M1 (AFM1) (Min et al., 2021), extending the food safety concern to dairy products. In Albania, AFM1 contamination in milk has also been reported (Tahiri et al., 2025), highlighting the downstream impact of field contamination on the broader food chain. Climatic conditions, humidity, temperature, agricultural practices, insect damage and storage conditions vary across different crops, affecting contamination levels (Valencia-Quintana et al., 2020).
 
Aflatoxin risk analysis
 
The aflatoxin risk index (ARI, %) is not a standardized global metric but rather a calculated value used in specific studies or models to estimate the likelihood of aflatoxin contamination in crops or food products (Chauhan et al., 2015). The ARI  is a predictive measure used in agricultural and food safety research to estimate the probability or severity of aflatoxin contamination.
ARI is typically derived from models that integrate:
• Weather data (temperature, humidity, rainfall).
• Crop susceptibility (e.g., maize, peanuts).
• Fungal growth conditions (A. flavus and A. parasiticus).
• Historical contamination data.
       
Monitoring ARI helps mitigate contamination in food supply chains and protect consumer health. Pre-harvest modeling and mitigation of aflatoxins in maize under changing climatic conditions have been extensively reviewed (Dövényi-Nagy et al., 2020), providing a scientific basis for climate-sensitive risk indices.
       
Country production comprises a wide range of crops, including small grains intended for human and feed as well as maize (Mato et al., 2024b). Despite increasing awareness at the European level, localized assessments of aflatoxin risk remain limited in Albania. Existing studies indicate a growing prevalence of mycotoxin contamination in maize and other cereals, yet there is a lack of predictive tools tailored to the country’s specific climatic and agricultural conditions. This gap hinders the development of effective monitoring and mitigation strategies, particularly in regions where traditional farming and storage practices may exacerbate contamination risks.
       
This study develops a simplified, temperature-based aflatoxin risk index (ARI) for Albania’s major maize regions from 2004 to 2024. It focuses on temperature thresholds linked to aflatoxin production to (i) measure variability in risk, (ii) identify high-risk areas and (iii) offer a practical early assessment tool amid climate change. The results aim to enhance food safety and inform adaptation strategies.

Study area
 
The study was conducted across major maize-producing regions of Albania Fier-Lushnjë, Durrës, Elbasan, Shkodër, Korçë and Gjirokastër-which are characterized by mediterranean influences and hot, dry summers (Fig 1). In contrast, the Korçë region has a temperate continental climate. The maize crop is typically cultivated from May to October. These regions were selected for their agricultural importance and varying vulnerability to heat stress and drought. The research project was developed within the research group on food toxins in the Department of Chemistry, Faculty of Natural Sciences, University of Tirana, during the period 2023-2025.


 
Data collection
 
Daily maximum air temperature data (T_max, °C) for the period 2004-2024 were obtained from regional meteorological monitoring systems. The analysis focused on the maize growing season, defined as May through September, corresponding to key phenological stages: vegetative growth (May-June), flowering (July), grain filling (August) and maturation (September). For each region and year, the number of days with maximum temperature exceeding 33°C was extracted, as this threshold is associated with enhanced aflatoxin production by A. flavus (Medina et al., 2014; Cotty and Jaime-Garcia, 2007).
 
Aflatoxin risk index
 
To quantify the climatic suitability for aflatoxin contamination, a temperature-based Aflatoxin Risk Index (ARI) has been developed (Medina et al., 2014). The ARI is defined as:

 

 

Where,
N_Tmax>33°C= Number of days during the growing season with T_max above 33°C.
N_total= Total number of days in the growing season (May-September).
       
The threshold of 33°C was selected based on experimental and modeling studies indicating optimal conditions for aflatoxin biosynthesis, even though fungal growth may occur at slightly lower temperatures (Medina et al., 2014; Cotty and Jaime-Garcia, 2007).
       
To facilitate interpretation, ARI values were categorized into six risk levels (Table 1).


 
Trend and spatial analysis
 
Temporal trends in ARI values were evaluated over the 20-year study period (2004-2024) to identify changes in climatic risk patterns. Regional comparisons were performed to assess spatial variability in aflatoxin risk across different agro-climatic zones.
       
Descriptive statistics, including mean ARI values and interannual variability, were used to summarize regional differences. The analysis aimed to identify high-risk regions and assess whether the frequency of critical temperature conditions has increased over time.
 
Assumptions and limitations
 
The proposed ARI model is based solely on temperature as the primary driver of aflatoxin risk. While temperature is a key factor influencing A. flavus growth and toxin production, other environmental variables-such as relative humidity, rainfall, soil moisture and postharvest storage conditions-also play a significant role.
       
Due to data limitations, these factors were not included in the present model. Therefore, the ARI should be interpreted as a proxy indicator of climatic suitability rather than a direct measure of contamination. Future studies should integrate multi-factorial datasets and validated predictive models to improve accuracy and reliability.

Temporal trends in aflatoxin risk index
 
Analysis of ARI data from 2004 to 2024 shows a clear increase in high-temperature conditions conducive to aflatoxin production in Albania’s main maize-growing areas. The percentage of days with maximum temperatures above 33°C during the growing season varied significantly from year to year, with a recent increasing trend. Periods of extreme summer heat led to higher ARI values, indicating a greater likelihood of favorable conditions for A. flavus growth and aflatoxin formation. Throughout several years of the study, ARI values in lowland regions exceeded the 60% threshold, indicating high to very high risk (Fig 2).


       
Significant spatial differences in ARI values were observed among the studied regions. Western lowland regions, including Fire-Lushnjë, Durrës and Elbasan, consistently exhibited the highest ARI values throughout the study period. These regions frequently fell within the “high” (41-60%) and “elevated” (61-80%) risk categories, reflecting persistent exposure to temperature conditions conducive to aflatoxin production.
       
Similarly, Shkodër region showed elevated ARI values, particularly in the summer months, likely due to the combined effects of high temperatures and coastal humidity. Gjirokastër recorded moderate to high ARI levels, with seasonal peaks in July and August, periods of intensified heat. In contrast, the inland region of Korçë consistently had lower ARI values, generally within the “low” to “moderate” risk categories (below 40%). This pattern reflects the moderating effect of higher altitude and temperate continental climatic conditions, which limit the number of days exceeding the critical temperature threshold.
 
Seasonal distribution of risk contamination
 
The distribution of high-risk days within the maize growing season was not uniform. The highest frequency of temperatures exceeding 33°C occurred during the mid-to-late summer months, particularly in July and August, corresponding to the silking/flowering and grain-filling stages of maize development. These stages are known to be particularly sensitive to fungal infection and toxin accumulation.
       
In early (May-June) and late (September) stages of the growing season, ARI values were substantially lower across all regions, indicating reduced climatic suitability for aflatoxin production. This seasonal pattern highlights the critical importance of mid-summer climatic conditions in determining overall contamination risk.
 
Regional risk classification
 
Based on ARI classification thresholds, the analyzed regions can be grouped into distinct risk categories. Durrës and Elbasan regions emerge as high-risk zones, with frequent classification in the “high” to “very high” categories. Shkodër and Gjirokastër can be considered moderate-to-high risk regions, exhibiting substantial interannual variability.
       
In contrast, the Korçë region represents a comparatively low-risk area, with ARI values rarely exceeding moderate levels. These distinctions reflect underlying climatic gradients and provide a basis for region-specific risk management strategies. These findings are in accordance with previous studies on aflatoxin occurrence in grain and maize from these regions (Topi et al., 2023; Mato et al., 2024a).
       
This study presents the first comprehensive climate-based assessment of aflatoxin risk in maize across Albania’s major agricultural regions over the last two decades, 2004-2024, beginning with the first reported incidence of maize contamination in Europe (Table 2). Contamination levels are influenced by plant and fungal genetics, management practices and prevailing climatic conditions (Chukwudi et al., 2021). The findings show a significant increase in high-temperature conditions conducive to A. flavus proliferation and aflatoxin biosynthesis, with pronounced spatial variability across western lowland and inland regions. These results align with and extend the growing body of evidence from neighboring Balkan countries and Southern Europe on the role of climate change in elevating mycotoxin contamination risks.


       
The elevated ARI values (>60%) in western lowland regions (Fier-Lushnjë, Durrës, Elbasan) align closely with climate warming patterns documented across the Balkan Peninsula and Southern Europe (Baranyi et al., 2015; Kos et al., 2018). Battilani et al., (2016) demonstrated that aflatoxin B1 contamination in maize is increasing across Europe due to climate change, with particular vulnerability in transitional zones such as Southern Europe and the Balkans. Our data support this trend, showing that Albania’s western regions, characterized by Mediterranean climates with hot, dry summers, are experiencing intensified heat stress during critical maize phenological stages. This pattern reflects the strong influence of regional climatic conditions on A. flavus proliferation and the associated risk of aflatoxin contamination.
       
The inland region of Korçë, with consistently lower ARI values (<25%, predominantly ‘low’ risk), represents a climate refuge due to higher altitude and temperate continental conditions. This spatial differentiation mirrors patterns observed in other temperate regions of Europe, where elevation-driven temperature gradients create microclimates less favorable for aflatoxin production. Such regional heterogeneity underscores the importance of localized risk assessments, as emphasized by Medina et al., (2014), who demonstrated that even small temperature increases of 2-3°C in transitional zones can substantially elevate aflatoxin risk.
       
ARI trends align with broader climate change in Southern Europe, where warming exceeds the global average, leading to increased aflatoxin contamination, especially during heat and drought events in Serbia and Romania (Battilani et al., 2016; Kos et al., 2018). These patterns support the idea that climate change is expanding aflatoxin risks across Europe, notably in transitional zones such as the western Balkans, where small increases in temperature can boost aflatoxin production.
       
The results reveal increasing vulnerabilities in Albania’s maize systems, with frequent ARI values exceeding 60% in western regions, indicating a high aflatoxin risk. Elevated temperatures boost fungal infections and poor drying and storage worsen contamination. The proposed ARI model provides a simplified and practical tool for assessing climatic suitability for aflatoxin contamination, particularly in data-limited environments. Its reliance on temperature thresholds enables straightforward implementation with readily available meteorological data, making it suitable for preliminary risk screening and early warning systems. However, this simplicity also represents a key limitation. Multiple interacting factors, including relative humidity, rainfall patterns, soil moisture, insect damage and storage conditions, influence aflatoxin production. By focusing exclusively on temperature, the ARI may overestimate or underestimate risk under certain environmental scenarios.
       
Research indicates that while the fungus can grow between 28°C and 33°C, aflatoxin levels peak at 33-35°C (Table 3). Temperatures below 30°C may support fungal growth but result in significantly lower toxin levels. Conversely, temperatures above 35°C typically hinder fungal growth, although some toxins may persist. Thus, this value serves as a practical, scientifically supported cutoff for identifying days at high risk of contamination. Lower thresholds, such as 30°C or 32°C, could overstate the risk by including days less conducive to substantial aflatoxin production (Cotty and Jaime-Garcia, 2007).


 
Albania’s emerging mycotoxin crisis in the balkan context
 
While Albania has received less scientific attention than neighboring Serbia, Romania and Croatia, preliminary evidence suggests similar, if not escalating, mycotoxin challenges. Topi et al. (2021, 2023, 2024) have documented the presence of Fusarium mycotoxins, Aspergillus and Penicillium toxins in Albanian cereals, with recent studies (Mato et al., 2024a) revealing high prevalence of mycotoxigenic fungi and AFB1 contamination in corn and wheat.
       
Our climate-based risk assessment provides crucial context for interpreting these contamination surveys. The high ARI values observed in western regions during specific years (e.g., 2015, 2017) predict elevated aflatoxin risk and help explain temporal variations in observed contamination data. Conversely, consistently low ARI in Korçë predicts this region should show fewer aflatoxin problems-a hypothesis that could be tested in future field surveys.
       
The downstream impacts of the food chain are already evident: Tahiri et al., (2025) recently documented aflatoxin (AFM1) contamination in milk consumed in Tirana, indicating that field-level aflatoxin contamination is translating into animal feed contamination and human exposure via dairy products. This underscores the urgency of our findings-climate-driven mycotoxin risks are not merely agricultural problems but human health threats that require integrated policy responses.
 
Agricultural adaptation in high-risk regions
 
Our identification of western lowland regions as high-risk zones suggests the need for targeted agronomic interventions. While our study does not directly test mitigation strategies, the literature (Dövényi-Nagy et al., 2020; Medina et al., 2014) supports the promotion of heat- and drought-tolerant maize varieties in Fier-Lushnjë, Durrës and Elbasan. Expansion of irrigation infrastructure to mitigate drought stress, which exacerbates fungal infection and aflatoxin accumulation. Adjustment of planting dates to shift flowering away from peak heat (June rather than July in some regions). Implementation of integrated pest management to reduce insect damage, a co-risk factor for A. flavus colonization. In contrast, Korçë’s low ARI status suggests it may become increasingly valuable for certified low-contamination maize production, with potential for premium market positioning. Our analysis of ARI trends over 2004-2024 reveals a clear upward trajectory in high-risk conditions, with western regions frequently exceeding ARI thresholds of 60% or more in recent years. This temporal pattern is consistent with broader climate warming trends documented for Southern Europe and the Balkans, which have experienced accelerated temperature increases exceeding global averages (Battilani et al., 2016; Dövényi-Nagy et al., 2020).
       
Dövényi-Nagy et al. (2020), in their comprehensive review of pre-harvest aflatoxin modeling in changing climates, found that Eastern and Central European regions are experiencing a gradual expansion of climatic conditions conducive to aflatoxin production. Our data suggest that Albania is at the center of this expansion zone. Specifically, the frequency of extreme heat years (defined as years with ARI >60% in multiple regions) has increased in the most recent decade (2015-2024) compared to the earlier period (2004-2014). Critical-window analysis (July-August) confirms that mid-summer heat stress, identified by Cotty and Jaime-Garcia (2007) as the primary driver of aflatoxin biosynthesis, has intensified. This temporal pattern aligns with documented extreme heat events in the Balkans (e.g., 2015, 2017, 2022 heat waves), which have been linked to substantial aflatoxin outbreaks in neighboring countries (Kos et al., 2018; Topi et al., 2023).
       
While this study contributes valuable regional insights, several limitations must be acknowledged and addressed in future work. Our ARI model relies exclusively on temperature, omitting critical drivers of aflatoxin production, such as relative humidity and rainfall. Soil conditions, such as soil moisture, pH and nutrient status, also influence both maize stress tolerance and fungal proliferation. These soil-level variables were not captured. Agricultural practices: Irrigation, variety selection, pesticide use and harvest timing substantially modify actual field-level risk. Postharvest conditions: Storage temperature, humidity control and pest management affect postharvest contamination dynamics, which are not reflected in the growing season ARI. Dövényi-Nagy et al. (2020) emphasized that integration of moisture and agronomic data typically improves model performance by 15-40%. Future Albanian studies should incorporate these variables to enhance predictive power.

This study demonstrates that rising temperatures associated with climate change are significantly increasing the climatic suitability for aflatoxin contamination in maize across Albania. The application of a temperature-based Aflatoxin Risk Index (ARI) revealed clear spatial and temporal patterns, with western lowland regions consistently exhibiting higher risk levels than inland areas. The findings highlight a growing vulnerability of national food systems to climate-driven mycotoxin contamination, particularly during critical crop development stages in mid-summer. The proposed ARI provides a practical and scalable tool for preliminary risk assessment, especially in data-limited contexts.
       
However, the model’s reliance on temperature alone represents a limitation and future research should integrate additional environmental and agronomic variables to enhance predictive accuracy. Strengthening monitoring systems and implementing targeted mitigation strategies will be essential to reduce aflatoxin risks and ensure food safety under evolving climatic conditions.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.