Food-borne mycotoxins pose one of the most significant food safety risks in lower- and middle-income economies in Asia and Africa. The negative impacts of naturally occurring fungal toxins, such as aflatoxins and fumonisins, on livestock health and growth have been well-documented for over 100 years. It has also long been understood that human consumption of extremely high levels of aflatoxins (e.g. in early harvested improperly dried maize) can be fatal; acute aflatoxicosis outbreaks have been periodically reported in countries like Kenya and India. Chronic exposure (intake of even relatively low levels of this naturally occurring fungal toxin) harms the liver and is associated with liver disease. 

New research from the Feed the Future Innovation Lab for Nutrition (NIL) tell us that exposure to mycotoxins through the diet is widespread in resource-constrained areas of the world such as Timor-Leste, Nepal, Uganda, and Mozambique. Additionally, exposure through the food system is associated with bad health outcomes, including infants being exposed in utero. The relationship of aflatoxin and health is further compounded by the ubiquitous nature of the exposure. These studies also reveal that mycotoxin mitigation is key to improving child nutrition and growth, and that action is urgently required.

Preliminary results from a birth cohort study in Uganda demonstrated that aflatoxin levels in mothers’ blood during pregnancy were significantly correlated with negative birth effects on the infants’ weight, head circumference, being born small-for-gestational age (SGA), and stunting at birth. In Nepal, infants whose mothers were exposed to aflatoxin during pregnancy showed a higher risk being born SGA (1). 

Mycotoxin exposure is a ‘First 1,000 Days’ concern. While the importance of ensuring diet quality for pregnant women is well-understood and integrated into messaging, ensuring food safety is relatively new. Emphasis must be placed on encouraging the importance of not just nutritious but also safe foods into health messaging and behavior change activities that aim to support nutrition goals. The 2013 Lancet Series on nutrition reported that “babies who are SGA (small for gestational age) have an increased risk of growth faltering in the first two years of life” with their estimates suggesting that 20% of stunting being attributable to poor growth during pregnancy.” (2)  Given the association of SGA and detectable levels of aflatoxins in mothers’ blood documented by NIL studies in Uganda and Nepal, the need to clean the food system is critical. (3) This may be just as important as improving access to safe water and improving knowledge and practices around water storage and usage.

Most mothers, infants and young children in the tropics are exposed to mycotoxin contamination in the food supply. The prevalence of aflatoxin exposure (defined as percent of people with detectable levels of aflatoxin) ranged in NIL studies from 81% in Timor-Leste to almost 100% in Uganda, with 94% exposure in Nepal and 90% in Mozambique. A critical finding across all studies, was the lack of association with either wealth or education of the household. Furthermore, nearly all households in these studies report purchasing some of their food implying contamination of the food supply at the market level and the need to consider strategies for intervention that go beyond those focused on household production. While many other factors contribute to poor pregnancy outcomes, ubiquitous dietary exposure to mycotoxins represents a public health concern that cannot be ignored. 

Aflatoxin levels are associated with other health conditions and co-morbidities. Our findings in Uganda suggest that where aflatoxin levels are high in the blood there is a greater likelihood of also seeing a) inflammation (a physiological reaction to disease threats), b) higher gut permeability, typically associated with environmental enteric dysfunction (EED), and c) co-morbidities including HIV, and possibly malaria and anemia. In other words, the greatest damage done by mycotoxins may be to people whose health is also under threat from other illnesses. There is substantial potential for linking actions associated with disease prevention, healthcare, WASH and education to improved knowledge of, and practices to manage, food safety. 

Implications for Policies and Programs 

Mycotoxin contamination arises at multiple points in the food system, from the field to the home (where pests attack or poor drying techniques and inadequate crop storage allow the mold to grow), and to the marketplace (where lack of quality control allows contaminated food to be sold). It is important to equip producers, traders and consumers with knowledge that can help them manage this issue. 

At the farm and household level, drying and storage technologies can make a difference. Relatively inexpensive technologies for drying and storage can be included in many agriculture and multi-sector programs. For example, NIL’s research has shown that the risk of aflatoxin exposure is reduced through the careful sorting of grains, use of locally constructed chimney driers, drying of grain off the ground (such as on plastic sheets), and the use of moisture meters and hermetically sealed bags. 

Potential for market-based and private sector interventions. Trader-focused interventions can improve food safety, such as ‘safety certification’ initiatives at market and brand level. Local industry producers of complementary foods for infants, maternal food supplements, and other food products, can all be supported to enhance the monitoring and quality control of the products entering local markets. 

Mycotoxin mitigation is a key to improving food safety and building local resilience. The journey to self-reliance will remain weak while resource-constrained nations continue to produce, market, and consume contaminated food products. There is important seasonal variability in the growth of molds, and some agro-ecologies are more conducive to toxin spread than others. This calls for careful sub-national assessments of risks, hotspots and plans for both prevention and remediation. Mycotoxin contamination is enabled by flooding and pests/disease outbreaks; such events weaken the integrity of crops themselves (higher humidity and stem borers open the way for molds to establish, for example), but also weaken farmers’ and traders’ ability to focus on food safety concerns. Programs seeking to build rural livelihood, market and nutrition resilience should consider incorporating specific mycotoxin management elements. 

NIL has conducted significant research on mycotoxins that reveals the urgent need for the global community to act now to reduce mycotoxin contamination and exposure in order to help some of our most vulnerable populations, infants, children, and pregnant women. Solutions will need to be comprehensive, ranging from increasing awareness at the household level, to improving crop drying and storage practices, to working at the policy level and conducting more assessments so we can better focus our mitigation efforts. By protecting people from mycotoxin exposure, we are also improving the health, well-being and productivity of future generations.

Footnotes

(1) Andrews-Trevino, J. Y. (2019). "Relatively Low Maternal Aflatoxin Exposure Is Associated with Small-for-Gestational-Age but Not with Other Birth Outcomes in a Prospective Birth Cohort Study of Nepalese Infants."

(2) Black et al. 2013. Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60937-X/fulltext.

(3) Note that any detectable level in the blood is unacceptable from a public health standpoint. There is no known science-based threshold below which ‘a little’ exposure would be considered as not harmful to the consumer.