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Value chain connects profitability with aflatoxin prevention practice

By Allison Floyd

University of Georgia, Peanut & Mycotoxin Innovation Lab

Research on the value chain in Ghana has shown the interrelated approaches that are necessary to reduce aflatoxin in peanuts and provided understanding that can foster development of seed-to-table interventions to improve the quality and quantity of the crop.

Research shows aflatoxin prevention interventions are most effective at the post-harvest stage, however farmers need the increased yield from improved varieties and growing techniques, and possibly a price premium for quality peanuts to be able to afford those interventions.


Women separate peanuts from the plant after harvest in Ghana. (Photo by Dave Hoisington)Women separate peanuts from the plant after harvest in Ghana. (Photo by Dave Hoisington)

 

While planting date, rainfall and temperature during the growing season certainly impact the growth of A. flavus and development of aflatoxin, the way that the crop is dried and stored seems to have a much greater impact on contamination levels.

Also, incentives at the buying point for low-aflatoxin peanuts must be carefully tailored to account for the cultural and economic practice of storing peanuts as a type of savings and selling off in small lots when cash is needed.

In the central Ghana village of Drobonso, researchers compared the level of aflatoxin in the crop that employed improved pest management and fertility compared with the traditional farmer practice.  Although the improved practices brought in higher yield, quality and economic return ($978 compared to $778 per hectare), the crops had only a minor difference in aflatoxin concentration when sampled immediately after harvest. That increased economic return may be even greater because improved practices reduce the amount of sort-outs.

Aflatoxin levels rose once the crop was dried, and rose higher without the use of inexpensive solutions, such as tarps to allow drying off the bare ground. Regardless of the level of aflatoxin at harvest, the crop dried on the ground had a higher level (153-226 µg/kg) compared with the peanuts dried on plastic tarps (29-80 µg/kg aflatoxin).

As these peanuts continued through the value chain, the crop that had few inputs in the field, was dried on the ground, and was stored in poly sacks with limited protection from the elements (the control treatment closest to current farmer practices) had an aflatoxin concentration of 1407 µg/kg. The peanuts that were grown under improved growing practices, dried on tarps and stored in hermetically-sealed bags had the lowest aflatoxin concentration (53 µg/kg). Adopting a single improved practice or two of the three possible improved practices resulted in aflatoxin concentrations between 100 and 600 µg/kg, creating further evidence of the necessity of linking all practices.

Farmers have very limited resources to invest in those drying and storage improvements, however. When PMIL scientists offered tarps for free, all farmers took them and over two-thirds used them to dry their groundnuts as instructed. But when tarps were offered at a subsidized price of $2.50, only 10% of farmers bought them. This shows how few resources are available to invest in aflatoxin preventing interventions and/or how little farmers understand and value aflatoxin control. Producing a more plentiful or valuable crop could be key in giving farmers’ flexibility to invest in aflatoxin-preventing technologies.

At the same time, work on the value chain also has shown a disconnect between incentives offered at the buying point for low-aflatoxin nuts and farmers’ desire to make the most profit from their crops.


Men dry peanut plants in Ghana. Proper drying is key to preventing aflatoxin contamination. (Photo by Dave Hoisington)Men dry peanut plants in Ghana. Proper drying is key to preventing aflatoxin contamination. (Photo by Dave Hoisington)

 

Very few farmers (less than 5%) offered a 15% premium over market price for groundnuts with aflatoxin levels below 15 ppb agreed to sell to the buyer when offered two to three months after harvest. The growers said they had already sold, were waiting for prices to increase, or were holding onto their crop as a form of savings.

The fact that farmers keep groundnuts in storage to speculate on prices and sell small quantities of nuts when cash is needed is an important factor in tailoring incentives for low-aflatoxin peanuts at the buying point.

Presenting incentives at each step in the value chain to deliver a high quality and safe peanut crop is critical if effective and sustainable value chains are to exist.

Published January 13, 2017