Factors influencing fumonisin B1 contamination in maize: insights from two production regions in Costa Rica

Maize (Zea mays L.) is an important cereal crop worldwide. Contaminated maize kernels pose a significant mycotoxin exposure risk for humans in Latin America. Fumonisins, the most prevalent mycotoxin in maize, typically occur during pre-harvest conditions leading to significant economic losses. Various factors, including weather conditions, may influence this contamination. This study aimed to determine the association between fumonisin B1 (FB1) contamination, prevalence of Fusarium verticillioides, weather conditions and kernel quality in the two primary maize production areas in Costa Rica (Brunca and Chorotega). All maize samples (100%) showed FB1 contamination, with higher concentrations in samples from Brunca region, consistent with the presence of F. verticilliodes. Weather conditions appeared to play an important role in this contamination, since Brunca region had the highest mean temperature and relative humidity after maize silking (R1) and the total monthly rainfall in this region was significantly higher during the last two months of maize cultivation (grain-filling and physiological maturity stages R3 to R6). Interestingly, this study found a negative correlation between grain damage and kernel contamination with FB1 and F. verticillioides. The concentration of mineral nutrients in kernels from both regions was largely similar. Most nutrients in kernels exhibited a negative correlation with FB1, particularly nitrogen. Zinc and phosphorus were the only nutrients in kernels showing a positive correlation with FB1 in samples from the Brunca region. The results highlight elevated levels of FB1 contamination in maize and contribute to a better understanding of pre-harvest factors influencing FB1 contamination in tropical conditions.

Review of good agricultural practices for smallholder maize farmers to minimise aflatoxin contamination

Maize is consumed world-wide as staple food, livestock feed, and industrial raw material. However, it is susceptible to fungal attack and at risk of aflatoxin contamination under certain conditions. Such contamination is a serious threat to human and animal health. Ensuring that the maize used by food industry meets standards for aflatoxin levels requires significant investment across the supply chain. Good Agricultural Practices (GAP) form a critical part of a broader, integrated strategy for reduction of aflatoxin contamination. We reviewed and summarised the GAP of maize that would be effective and practicable for aflatoxin control within high-risk regions for smallholder farmers. The suggested practicable GAP for smallholder farmers were: use of drought-tolerant varieties; timely harvesting before physiological maturity; sorting to remove damaged ears and those having poor husk covering; drying properly to 13% moisture content; storage in suitable conditions to keep the crop clean and under condition with minimally proper aeration, or ideally under hermetic conditions. This information is intended to provide guidance for maize growers that will help reduce aflatoxin in high-risk regions, with a specific focus on smallholder farmers. Following the proposed guidelines would contribute to the reduction of aflatoxin contamination during pre-harvest, harvest, and post-harvest stages of the maize value chain.

Spatiotemporal assessment of post-harvest mycotoxin contamination in rural North Indian food systems

The spatiotemporal trends in aflatoxin B1 (AFB1), fumonisin B1 (FB1), and deoxynivalenol (DON) accumulation were analyzed in a range of food commodities (maize, groundnut, pearl millet, rice, and wheat) in village settings in Unnao, Uttar Pradesh, India. Samples (n = 1549) were collected across six communities and six time points spanning a calendar year and were analyzed for mycotoxins using enzyme-linked immunosorbent assays. AFB1 and FB1 were common across surveyed villages, with moderate to high detection rates (45-75%) observed across commodities. AFB1 levels in maize and groundnuts and FB1 levels in maize and pearl millet frequently exceeded regulatory threshold levels of 15 μg/kg (AFB1) and 2 μg/g (FB1). DON was analyzed in wheat, with 3% of samples yielding detectable levels and none exceeding 1 μg/g. In rice, AFB1 levels were highest in the bran and husk and lower in the kernel. Commodity type significantly influenced AFB1 detection status, while commodity type, season, and visual quality influenced samples' legal status. Storage characteristics and household socioeconomic status indicators did not have significant effects on contamination. No significant effects of any variables on FB1 detection or legal status were observed. Data on mycotoxin contamination, combined with data on local dietary intake, were used to estimate spatiotemporal mycotoxin exposure profiles. Estimated seasonal per capita exposure levels for AFB1 (5.4-39.3 ng/kg body weight/day) and FB1 (~0-2.4 μg/kg body weight/day) exceeded provisional maximum tolerable daily intake levels (1 ng/kg body weight/day for AFB1 and 2 μg/kg body weight/day for FB1) in some seasons and locations. This study demonstrates substantial dietary mycotoxin exposure risk in Unnao food systems and serves as an evidentiary foundation for participatory food safety intervention in the region.

A Fumonisin Prevention Tool for Targeting and Ranking Agroclimatic Conditions Favoring Exposure in French Maize-Growing Areas

The levels of fumonisins (FUMO)-mycotoxins produced by Fusarium verticillioides-in maize for food and feed are subject to European Union regulations. Compliance with the regulations requires the targeting of, among others, the agroclimatic factors influencing fungal contamination and FUMO production. Arvalis-Institut du végétal has created a national, multiyear database for maize, based on field survey data collected since 2003. This database contains information about agricultural practices, climatic conditions and FUMO concentrations at harvest for 738 maize fields distributed throughout French maize-growing regions. A linear mixed model approach highlights the presence of borers and the use of a late variety, high temperatures in July and October, and a water deficit during the maize cycle as creating conditions favoring maize contamination with Fusarium verticillioides. It is thus possible to target a combination of risk factors, consisting of this climatic sequence associated with agricultural practices of interest. The effects of the various possible agroclimatic combinations can be compared, grouped and classified as promoting very low to high FUMO concentrations, possibly exceeding the regulatory threshold. These findings should facilitate the creation of a national, informative and easy-to-use prevention tool for producers and agricultural cooperatives to manage the sanitary quality of their harvest.

Influence of socio-economic and agronomic factors on aflatoxin and fumonisin contamination of maize in western Kenya

Consumption of maize contaminated with mycotoxins has been associated with detrimental health effects. A farm survey covering 116 push-pull and 139 non-push-pull cropping systems was conducted to determine the socio-economic and agronomic factors that influence farmers' knowledge on incidence and contamination of maize by ear rots and associated mycotoxins in western Kenya. All the respondents were smallholder farmers between the ages of 23 and 80 years, with 50% of them being female. Maize samples were collected from the standing crop in the field of each interviewed farmer and analyzed for aflatoxin and fumonisin. Only a small proportion of farmers had knowledge of aflatoxin and ear rots in maize. Overall, less than 20% of maize samples were contaminated with both aflatoxin and fumonisin, and more maize samples were contaminated with fumonisin as compared to aflatoxin. Proportions of maize samples containing higher than the acceptable Kenyan regulatory threshold (10 µg/kg) for aflatoxin and European Commission regulatory threshold (1,000) µg/kg for fumonisin were lower in maize samples from push-pull cropping system. Age of farmer and county of residence were significantly and positively associated with knowledge of aflatoxin, while cropping system, county of residence, and level of education were positively associated with knowledge of maize ear rots. There was strong correlation between knowledge of maize ear rots and knowledge of aflatoxin. Levels of both aflatoxin and fumonisin were significantly and positively associated with the use of diammonium phosphate (DAP) fertilizer at planting. Aflatoxin levels were also positively associated with stemborer damage. Agronomic practices were not significantly different between push-pull and non-push-pull farmers. However, use of DAP fertilizer was the most important agronomic factor since it was associated with both aflatoxin and fumonisin contamination of maize. These results imply that creating awareness is key to mitigation of ear rots and mycotoxin contamination of maize. The results also suggest that the levels of aflatoxin and fumonisin in maize in western Kenya were influenced both by pre-harvest agronomic practices and by the cropping system adopted, push-pull or not.

Mycotoxin management in a developing country context: A critical review of strategies aimed at decreasing dietary exposure to mycotoxins in Zimbabwe

Mycotoxins are unavoidable environmental contaminants, which are found throughout the food chain, particularly in cereals. Mycotoxin management is not effective in developing countries, such as Zimbabwe, due to resource constraints, yet human health risk is evident. Various practical mitigation strategies that can be employed to decrease human dietary exposure to mycotoxins as a means of preliminary steps towards risk management are discussed. These strategies were stratified into two categories. First, crop/commodity-centred strategies, mainly the pre-harvest actions of cultivar selection, bio-control, as well as good agricultural practices (GAP), and the post-harvest actions including timeous harvesting, appropriate drying and storage technologies, are elaborated making use of hazard analysis critical control points (HACCP) principles. The role of legislation is also explored as a crop/commodity centred mitigation strategy. Second, human-centred strategies anchored on dietary diversity and the use of socio-cultural approaches as a direct means of reducing mycotoxin exposure are discussed. Finally, an integrated science-based mycotoxin management strategy, encompassing targeted legislation on mycotoxins, consumer education and information sharing, human and institutional capacity building, training and financing, is suggested in addition to GAP, as a means of reducing human health risk associated with mycotoxin exposure in Zimbabwe.HighlightsFarm-to-fork HACCP-based mycotoxin managementHuman-centred mycotoxin management approaches are keyAgronomy, technology and legislation critical in reducing mycotoxin exposure.