Hot on the heels of deadly aflatoxins in southern Africa

Aflatoxins are cancer-causing, growth-retarding, and immune system-suppressing poisons produced by Aspergillus molds during crop growth or in storage. When aflatoxin-contaminated food and feed are ingested, aflatoxins severely affect human and animal health. Children under five years are particularly vulnerable, with aflatoxin exposure stunting their growth and development and damaging their immune system.

Aflatoxins are cancer-causing, growth-retarding, and immune system-suppressing poisons produced by Aspergillus molds during crop growth or in storage. When aflatoxin-contaminated food and feed are ingested, aflatoxins severely affect human and animal health. Children under five years are particularly vulnerable, with aflatoxin exposure stunting their growth and development and damaging their immune system.

In Mozambique, aflatoxins have been linked to a high prevalence of liver cancer. The high levels of aflatoxin often found in agricultural commodities produced in the southern Africa region have also impeded exports to countries with tight aflatoxin regulations and enforcement.

Research carried out by IITA in Malawi, Mozambique, and Zambia shows that groundnut and maize in farmers’ fields, stores, warehouses, and markets have high concentrations of aflatoxins, more so in groundnut. In Malawi, for instance, maize and groundnut from 22 districts collected between the 2014 and 2015 cropping seasons showed that at least 28% of the grains harvested were unsafe for human consumption as per US regulation limits of 20 parts per billion (ppb). Furthermore, groundnut was more prone to aflatoxin contamination than maize, and contamination levels were higher in the southern than the northern part of the country. In Zambia, 30–80% of the groundnut in the sampled sites was also found to be unsafe for human consumption, compared to only 2–5% for maize. In Mozambique, aflatoxin contamination in groundnut and maize was found to be as much as 350 and 30 times higher than the US regulation limits, respectively. Exports of Mozambican groundnut to European Union (EU) countries have, in many cases, been rejected because of exceedingly high levels of aflatoxin contamination. This has severely affected the livelihoods of smallholder groundnut farmers who produce almost 100% of the exported crop.

Officials from Malawi including DARS, visit the Aflasafe productin plant in the Business Incubation Platform in IITA/Nigeria.

To tackle the challenges posed by aflatoxins in southern Africa, IITA and its partners in Malawi, Mozambique, and Zambia have developed and are testing an innovative biocontrol product called Aflasafe™, which competitively displaces aflatoxin-producing isolates of the Aspergillus fungus using non-aflatoxin-producing isolates of the same fungus when applied in the right amounts and at the right time in maize and groundnut fields.

To date, IITA has developed five AflasafeTM biocontrol products: AflasafeTM ZM01 and AflasafeTM ZM02 (Zambia), AflasafeTM MWMZ01 (regional product for Mozambique and Malawi), AflasafeTM MZ02 (Mozambique), and AflasafeTM MW02 (Malawi) and is currently evaluating them in maize and groundnut fields in these countries. IITA is targeting to register at least one AflasafeTM product in each of these countries by 2017.

Evaluating the field efficacy of Aflasafe TM  products

In Malawi, evaluation through field demonstrations of AflasafeTM products is in its second year, covering 11 districts and 22 Extension Planning Areas (EPAs) across three agroecological zones. Six tons of AflasafeTM products (MWMZ01 and MW02) were imported into the country and are being used for these field and on-station evaluations. For each AflasafeTM-treated field, a corresponding untreated field is being used for comparison. Comparative analyses show a reduction of between 86 and 100% in maize, and 77 and 99.9% in groundnut samples from the AflasafeTM-treated fields.

Additionally, the AflasafeTM component of the Malawi Improved Seed Systems and Technologies (MISST) project has applied the biocontrol product in about 440 maize and groundnut farmers’ fields in the 2016–2017 farming season. The 440 farmers (220 maize and 220 groundnut) were spread across selected districts including Mzimba, Lilongwe, Mchinji, Dedza, Ntcheu, Balaka, Machinga, Mangochi, Blantyre, Chikwawa, and Nsanje. Two EPAs from each district were selected for the trials, with each EPA having at least 10 maize and 10 groundnut farmers.

In Mozambique, 312 groundnut farmers and 123 maize farmers from different agroecological zones of Central and Northern regions, covering a total of 435 farmers’ fields (312 groundnuts and 123 maize), participated in the AflasafeTM field efficacy trials. Aflatoxin contamination in non-AflasafeTM-treated control fields were found to range from 3 to 1516 ppb for groundnut, and from 2 to 639 ppb for maize. On the other hand, groundnut fields treated with AflasafeTM MZ02 showed aflatoxin contamination ranging from non-detectable levels to just 36 ppb, with only five groundnut fields (6%) treated with AflasafeTM MZ02 exceeding the 20 ppb US regulation aflatoxin threshold. In maize, the AflasafeTM MZ02-treated fields recorded aflatoxin contamination ranging from non-detectable levels to 24 ppb, with only one AflasafeTM MZ02-treated field (2%) exceeding the US aflatoxin regulation limits.

Zambian Aflasafe ZM01

Developing a regional aflatoxin solution

During the 2015/2016 crop season, IITA successfully developed and tested the first regional AflasafeTM biocontrol product (AflasafeTM MWMZ01) in Malawi and Mozambique. The non-aflatoxin-producing fungal isolates used to develop the regional AflasafeTM product are specific to Malawi and Mozambique, but have the same lineage. About 200 maize and groundnut farmers’ fields each in Mozambique, and 110 maize and groundnut farmers’ fields each in Malawi were treated with the regional AflasafeTM product. Most of the maize (94%) and groundnut (97%) sampled from farmers’ fields treated with AflasafeTM MWMZ01 in each country were found to be safe for human consumption, compared to the maize (50%) and groundnut (30%) sampled from the non-AflasafeTMtreated control fields. These results suggest that a regional Aflasafe product can be registered and effectively deployed across southern Africa.

Enhancing capacities and infrastructure

IITA organized a training in Malawi, Mozambique, and Zambia in collaboration with the District Agricultural Development Officers (DADOs) for maize and groundnut farmers and field extension officers. Participants were briefed on the basics of aflatoxin and efforts to minimize contamination using AflasafeTM, as well as good management practices to improve crop quality. Both farmers and extension officers had the hands-on opportunity to apply AflasafeTM in the field. A total of 2186 participants (1305 males and 881 females) have been trained on the use of AflasafeTM and other good management practices. Of these, 350 are agricultural officers while 1836 are farmers. A total of 750 farmers have so far benefited from the use of AflasafeTM to manage aflatoxin in their fields in the 2015/16 and 2016/17 cropping seasons.

In Mozambique, 579 small-scale farmers (386 men and 193 women), four groundnut and maize associations (each with 50 members), and 49 individuals from the maize private sector received 3 days’ training on aflatoxins and AflasafeTM use for aflatoxin mitigation during the 2016 crop season. The trainees came from Central and Northern Mozambique.

IITA also established and/or rehabilitated aflatoxin research and training laboratories in Malawi, Mozambique, and Zambia to improve support infrastructure and to contribute to building the capacity of research staff. New facilities were established in Mozambique and Zambia, and in Malawi, a research building was donated by DARS which IITA rehabilitated with the required equipment. Technicians were also recruited and trained on surveillance, aflatoxin detection, fungal identification, and related research on aflatoxin in the three countries. In addition, PhD students from the three countries are being trained at the Plant Pathology Department, University of Arizona, USA.

Introducing AflasafeTM to Zambia’s private sector

In Zambia, two aflasafe biocontrol products: AflasafeTM ZM01 and AflasafeTM ZM02 have been tested in on-farm conditions under different agroecological zones and have been found to effectively reduce aflatoxins in maize and groundnut by up to 99%.

In 2016, IITA partnered with Profit Plus and Share Africa-Zambia—a private company involved in peanut butter processing. Profit Plus purchased 2 tons of AflasafeTM from IITA and handed these to Share AfricaZambia which distributed the product to their farmers. For distribution, trained lead farmers and agro-dealers were identified as channels for AflasafeTM distribution to farmers while also ensuring the adherence to recommendations and protocols for proper AflasafeTM application in the field. After crop harvest and the processing of groundnut treated with AflasafeTM to produce peanut butter, aflatoxin detected in the final product was less than 2 ppb. This was a very positive outcome for the peanut butter processor as their product would meet aflatoxin safety regulations for export.

Furthermore, we demonstrated that farmers receiving a premium price for products meeting EU’s aflatoxin safety limits of 4 ppb would make a profit of around $1500 compared to just $280 for non-AflasafeTM users. With the successful pilot study, this prompted the private sector, Share Africa-Zambia, to invest 25% in importing AflasafeTM products into the country for the 2016/2017 cropping season.

Strengthening partnerships

Partnerships are key to meeting our aflatoxin eradication targets in the region. In Zambia, IITA partners with the Zambia Agriculture Research Institute (ZARI), the National Institute for Scientific and Industrial Research (NISIR), Profit Plus, and Share Africa-Zambia. In Mozambique, IITA works with the Pesticides’ Registration Unit at Mozambique’s Ministry of Agriculture, Novos Horizontes (a poultry and poultry feed producer based in Nampula), and Universidade Pedagogica de Mocambique for capacity building. In Malawi, IITA collaborates with the Department of Agricultural Research and Services (DARS), the Department of Agricultural Extension Services (DAES), the Pesticide Control Board (PCB), the Malawi Program on Aflatoxin Control (MAPAC), and the One Acre Fund (OAF).

ORCID: 0000-0003-4780-4850, 0000-0003-2422-4298

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