By Joyce Ojanji
Fresh cassava roots are highly perishable with some studies showing a shelf-life of less than 72 hours after harvest and post-harvest losses of about one in four (more than 23%) for freshly harvested roots.
To preserve the crop, farmers especially in the Western and Nyanza regions of Kenya, where cassava is grown extensively, have often relied on the traditional open sun drying method.
However, this method has not been efficient as the cassava does not dry quickly enough to meet customer demand and the product is susceptible to contamination from soil, wind, and birds, among others. Also, extreme weather conditions and rain leave the cassava vulnerable to toxic molds that can grow when using the slow open-air drying process.
It is in this regard, that in Busia County, Western region, a key producer of cassava, farmers are shifting to using solar driers. Asing’e aggregation center, with a membership of 50 members, is one of the farmer groups that was supported to receive one of these driers.
According to Josephine Okolodi, leader of the farmer group, when using the open-air drying method, it takes Asing’e three to four weeks to fulfill an order of 10 metric tons. The dryer however reduces the fulfillment time to just one week. The hybrid dryer also improves the quality of the crop by reducing its exposure to weather elements and mitigating the risk of the spread of toxic molds.
“Drying cassava on an open ground is tiresome and very untidy as it takes two to three weeks for the cassava chippings to dry completely. We have to be on the guard to avoid the cassava from being contaminated by birds, winds, and soil,” Okolodi narrates, adding that extreme weather conditions and rain favor the growth of toxic molds using the process.
In an effort to improve the quality of their dried cassava and cassava value chain, the farmers were given a cassava solar drier that costs about shs. 500,000 (about USD 5000) by Bountified International working with Self Help Africa (SHA).
“I prefer the cassava solar drier because it is fast and convenient in drying the chipping. Once you place the chippings in the drier, you don’t have to spend much time checking on the birds and worrying about climate change,” Okolodi says.
She adds that the dryer has increased their income by decreasing the drying time and expanding their capacity to fill more orders for more customers. Currently, the center provides cassava chippings and drying services to around 100 farmers in their community.
According to Geoffrey Nyamota of Bountified International, the cassava solar drier support was to improve the hygiene of the dried cassava by avoiding contamination. He says their aim was also to improve access to the market for the aggregation centers in Busia.
“Initially, farmers were using the traditional method of open sun drying. This method is prone to contaminations due to dust, birds’ droppings, crawling insects, and formation of molds,” Nyamota says.
“Open-drying is not an efficient way to dry cassava and is more difficult to meet stringent standards for sale. The cassava does not dry quick enough to meet customer orders and is susceptible to contamination.”
A cassava solar drier is made up of dry house plastic paper supported with strong metals and some flat net layouts inside where the chippings are placed.
It is fitted with windows that act as ventilators for proper aeration to avoid excess heat in the dryer. The plastic paper absorbs more heat and when it’s rainy, the absorbed heat is used to dry the cassava chippings.
To use it, the fresh cassava roots are peeled and washed in running water. They are then sliced using a motorized chipper. The chippings are then distributed and uniformly spread on the net trays in the drier.
For the chippings to dry completely, it takes three to four days when it is sunny and five days when it’s rainy.
The turning of the chippings is done for uniform drying only in the morning. During the day, they use a thermometer to measure the temperatures. If they are above 50 degrees Celsius, windows are opened for better ventilation to avoid excess heat which may affect the end product of the cassava. The best temperatures for the best results are between 45 degrees Celsius to 48 degrees Celsius.
When the temperatures are too high, there will be so much moisture in the drier, hence accelerating mold formation on the chippings. Also, when the temperatures are too low, the chippings will not dry completely and thus, become yellow in color due to molds and aflatoxins.
According to Nyamota, the drier has cushioned farmers from post-harvest losses and saves time and costs involved.
Ebukoro Peter, a member of the Asing’e aggregation group says that the cassava chippings dried in the solar drier are white and can be mixed with wheat flour when ground to make chapati.
“When the right temperatures are maintained in the solar drier, the cassavas are always white and clean to attract customers,” he says.
He narrates that when they were drying cassava on bare ground, and storing it by heaping on the bare floor and in old containers, the cassava was prone to aflatoxin contamination- this can result in serious health conditions including cancer. A fact that has been confirmed by a study conducted in Kumi district in Uganda.
Simon Okedi, a cassava farmer, explains that the drier has a capacity of carrying almost three tons of wet cassava chippings at a go, which comes to about 700 to 800 kilograms when completely dry.
“We harvest in bulk and all the cassava chippings are put in the drier at once. It gives us an easier time as we only wait for four days for them to dry up,’’ he says.
“Open drying is only favorable when it is sunny. When it is rainy, the chippings tend to have some molds. But for us, we don’t have to worry during the rainy season because the drier is all-seasoned. Plastic paper is able to absorb heat and use it during the rainy season. The quality still remains the same whether it is rainy or sunny.”
However, he says that the drier cannot withstand harsh weather conditions for a long time. “A continuous rainy and windy season tampers with the plastic paper and therefore leads to some leakage hence affecting the end product of the chipping. The plastic paper is not strong enough to withstand the strong winds and rains,” Okedi explains.
He adds that during the day, when the temperatures are high, they are unable to do the turnings in the solar drier. They can only check inside the drier in the mornings or late in the evenings.
According to Leonard Omongin, the group’s treasurer, they are now selling their cassava at shs. 60 (more than half a dollar) compared to a previous retail price of shs. 40 (less than half a dollar) per two-kilogram tin.
Omongin says that the yellow chippings, with molds, could not attract customers hence they were forced to sell them at a throw-away price.
“Right now, even before we take the cassava to the market, customers buy them at our Aggregation Centre,’’ he notes.
So far, two other cassava solar driers have been installed in Busia County, at Tangakona and Namasango Aggregation centers. Homabay County also has one cassava solar drier.
“We are focusing on cassava-producing counties to be able to improve their productivity. Since we started the installation of the driers, it has improved the market demand for the cassava,’’ Nyamota says.