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Can GM maize help combat aflatoxin menace in Kenya?

maize

Farmers spread their maize to dry in Kibwezi. FILE PHOTO | NMG

Genetically modified crops, also referred to as GM crops, have become the fastest adopted crops in the world since they were first commercialised in 1996. In Kenya, the government approved the commercialisation of insect-resistant cotton known as Bt cotton in 2020.

The GM cotton is named after the bacteria that confers the insect resistance characteristic — Bacillus thuringiensis (Bt).

The Bt cotton variety was introduced to help revamp the cotton industry and contribute to one of the government’s Big 4 Agenda — manufacturing. The cotton variety will improve crop yields by controlling pests but with less pesticide application.

Currently, the country is considering the approval and commercialisation of Bt maize.

The decision to approve the Bt maize now lies with the Cabinet after the National Biosafety Authority and supporting agencies conducted the requisite assessment for any risks posed to the environment and health of humans and animals as well as socio-economic considerations.

The Bt maize under consideration is anticipated to help tackle maize pests in the field, including the fall army worm, and improve the yields but with less inputs.

As we make this consideration, the advantage we have as a country is that there is now a body of knowledge out there on the safety of Bt maize as it has been approved for food, feed and cultivation since 1996 in 26 countries, including South Africa, Egypt and Nigeria in Africa.

Across different geographies, Bt maize has demonstrated the ability to resist insect damage and therefore increase the yield, but also decrease the use of pesticides.

Although the intended purpose for Bt maize is insect protection, less known to the public is that it has a secondary benefit from a public health perspective, especially in Kenya — reducing mycotoxin contamination.

Mycotoxins are toxic compounds that are naturally produced by certain types of fungi. Two of the most important mycotoxins in maize are aflatoxins and fumonisins.

In Kenya, aflatoxin is the more prevalent mycotoxin produced primarily by the fungi Aspergillus flavus that commonly infects food crops such as maize, peanuts, pistachios, and almonds.

Aflatoxins when consumed by humans are known to impair child development, suppress the immune system, cause cancer and, in severe acute exposure, death.

Aflatoxicosis (toxicity caused by aflatoxin) has been a perennial problem in Kenya and Africa as a whole. It resulted in 317 reported cases and the death of 141 people in Kenya in 2004 and 2005 respectively.

It is highly likely that it is causing more harm than is officially reported and documented every year. Over the years we have also witnessed huge stocks of maize at the National Cereals and Produce Board having to be destroyed by the authority due to high levels of aflatoxins.

In March 2021, Kenya banned the importation of maize from Tanzania and Uganda due to suspected high levels of aflatoxin, disrupting trade and resulting in a diplomatic tiff.

This points to the need for sustainable methods of managing aflatoxins to protect the health of the public but also for trade, particularly in maize that is a staple food in the region.

Insect damage is universally recognised as an important factor in the spread of diseases associated with most mycotoxins in maize. Other factors like weather conditions, location, degree of insect damage and hybrid type may also come into play.

The lower mycotoxin content in Bt maize compared to conventional varieties is associated with a lower incidence of insect attack.

Insects promote fungal colonisation by spreading fungal spores and creating wounds in kernels on which the germination of fungal spores is favoured during cultivation and storage, resulting in mycotoxin accumulation in grain. It is also hypothesised that a reduction in plant health resulting from insect damage may indirectly affect mycotoxin levels.

Methods that reduce insect damage in maize, that may include growing of Bt maize, can also reduce risks of fungal infestation, and subsequently aflatoxin and other mycotoxin contamination. Therefore, Bt maize offers another tool to tackle the perennial aflatoxin menace in Kenya.

This is of particular importance in this part of the world where farmers typically do not employ management strategies because they may not be aware of the mycotoxins, are unaware of the available mitigating technologies, or the technologies are labour and cost-prohibitive.

Even though it has been demonstrated that the adoption of Bt maize can reduce exposure to mycotoxins, it cannot by itself completely eradicate the problem of aflatoxin in human and animal diets.

The recommended strategy to improve food safety and health is an integrated approach to controlling mycotoxins along the maize value chain.

This includes tapping into genetic resistance resources, insect management, managing toxigenic (toxin producing) fungus at farm level using bio-control agents like Aflasafe for controlling aflatoxin, postharvest grain drying and cleaning methods whilst controlling grain damage, and development of risk assessment tools that account for the impact of climate change on evolving mycotoxin risks in maize.

The problem with genetic engineering of crops is that there has been, in my opinion, inordinate focus on the perceived risks posed by the technology over the benefits.

It is important to note that the technology was never developed to cause harm but as an additional tool to address food and nutritional security and our collective health.

There is no technology that is without risk, the key is to ensure that the benefits outweigh risks, and the identified risks are managed to acceptable levels. This has been vividly demonstrated by how the world has combated the Covid-19 pandemic.

Dr Liavoga is a researcher and food safety expert. [email protected]