Aflatoxin: An Invisible Threat to Food Security in Rural Communities

June 7 is recognized by the United Nations as World Food Safety Day. To raise awareness of the importance of food safety, we asked our long-time volunteer and Advisory Board member, Don Jacobson, to help explain aflatoxins, the negative impacts, and how difficult it is for rural communities to combat the spread. Don is a retired biochemist whose career focused on research & development for both General Mills and Pillsbury.

Groundnuts are a major staple crop in Malawi

Bountifield has worked for almost ten years to reduce the drudgery and improve the yield of groundnut (peanut) farming in Malawi. As a greater benefit, mechanical groundnut shelling, coupled with proper drying and storage, significantly reduces the negative impacts of aflatoxin, thus improving the value of the groundnuts, and the health and well-being of its consumers.

Aflatoxins are poisonous carcinogens produced by certain molds (Aspergillus flavus and Aspergillus parasiticus) which grow in soil, decaying vegetation, hay, and grains. When the mold is mature it can be seen but in the early stages it can go undetected and proceed into the food supply. They are regularly found in improperly stored staple crops such as cassava, chili peppers, millet, peanuts, rice, sweetcorn, wheat, and a variety of spices among others. Animals fed contaminated food can pass aflatoxin into eggs, milk products, and meat. No animal species is immune to the acute toxic effects of aflatoxins.

High doses of aflatoxin can cause serious illness and death in both animals and humans. It can lead to an increased risk of liver cancer and suppressed immune systems, resulting in increased susceptibility to diseases such as malaria, and reduced effectiveness of vaccines. While adults have a higher tolerance for aflatoxin exposure, children are particularly affected. The United States Agency for International Development (USAID) estimates up to 30 percent of global cases of childhood stunting and delayed development is linked to aflatoxin.

According to the World Health Organization, aflatoxin destroys an estimated 25 percent or more of the world’s crops each year. While the molds that produce the toxin are found throughout the globe, the systems to prevent contamination vary greatly. In the United States, farming techniques and storage protocols have, for the most part, eliminated the impacts of aflatoxin. The USDA has set standards on acceptable levels in grains. European Union nations have similar limits. Testing occurs regularly from harvest to consumption, significantly decreasing the risk of exposure to the consumer. However, the resources to take these precautions are not as readily available in many low- and middle-income countries. There is limited infrastructure to adequately test crops and a lack of safe storage capacities to reduce the growth of the molds.

Woman arranging groundnuts into the Mandela Hut

Traditional harvesting and postharvest processing techniques also exacerbate the growth. Consider groundnuts in Malawi. After they are lifted from the ground the nuts need to be quickly dried and processed. Sadly, effective drying technology is not readily available. One traditional method for drying within communities is to place the complete plants in a circle to form a hut with a hollow center, called a Mandela Hut. With the nuts facing in toward the hollow of the hut, they are protected from birds and other varmints. The nut’s moisture is somewhat reduced within the hut, but not to a significant degree. The mold can be growing both on the outside shell of the nut or inside on the nut itself.

Example of a Mandela Hut

Shelling is an arduous task to say the least. Envision shelling groundnuts by hand every day for one or even two months! It is exceptionally hard on the fingers. To mitigate the raspy abrasion, women, who do most of this work in sub-Saharan Africa, throw water on the nuts to soften them in a process called “wet-shelling.” Because moisture makes it easier for the toxins to spread, the practice of wetting the nuts can assist in the transfer of the mold from one nut to another. Even if there is only one contaminated nut, the whole lot is now completely contaminated.  

Women shelling groundnuts by hand

In addition to implications on health and food safety, there are also negative economic impacts that affect farmers. Because many countries have high standards for acceptable levels of aflatoxin, it is difficult for groundnut producers to meet the necessary criteria to access new and diverse markets. Due to a lack of infrastructure, the exact economic impact on the smallholder farmer is unknown, but it is certain that buyers for the European markets are reluctant to import groundnuts from wet-shelled sources.

By eliminating the addition of water from the shelling process, negative health and economic impacts are significantly reduced. Mechanical shellers, such as the Bountifield designed peanut sheller, accomplishes just that. While the advantage of hand shelling is that it produces almost 100 percent whole nuts, the Bountifield sheller is up to 15 times faster. Five different size “screens” are provided to accommodate five different varieties of groundnuts while allowing only two to five percent broken or split nuts. It is easily transported, so the tool can also be rented to other farmers in nearby villages and has a potential payback of one season. Additionally, the improved efficiency for the shelling process saves women more time in their day. It also provides the possibility of selling the nuts for an additional income. To further reduce the drudgery and time for the task of shelling, and to be able to shell more nuts at a time, Bountifield is now also exploring electric or gasoline fueled motorized shellers.

Bountifield’s groundnut sheller

While tools like the Bountifield sheller are important to help fight aflatoxin and improve the quality of groundnuts in sub-Saharan Africa, there is still a need to improve testing, increase education on safe handling practices, improve better drying techniques, and disseminate more storage solutions for rural communities such as hermetic storage bags.

Finding ways to mitigate the spread of aflatoxin is vital to decreasing postharvest loses and improving food security. Especially because the toxin can contaminate crops and food unknowingly, adjustments to how crops are handled, processed, and stored postharvest in the absence of testing capabilities are important in order to decrease the risk of consumption by both humans and animals. Those of us who have worked in food product development here in the United States and European Union nations have the necessary technology and quality controls for making sure that our nuts are safe to eat. The absence of this infrastructure in sub-Saharan Africa requires focusing on solutions similar to Bountifield’s. These mitigation efforts help produce a cleaner, healthier crop, improving the nutrition of rural communities.