Scientist on a mission to curb deadly aflatoxin

Friday August 30 2019
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Dr Isaiah Muchilwa demonstrates to Purity Jerotich and Sylvia Okello how his mootle checks moisture levels in cereals, vegetables and fruits. According to him, most farmers rely on the sun to dry their maize yet being in the tropics makes the country receive a lot of rains. PHOTO | STANLEY KIMUGE | NMG


The small plastic tin placed on a sack of beans resembles any other, until one notices what looks like a digital clock attached to the lid.

The ‘clock’ shows a figure and a percentage and keeps blinking, perhaps affirming the reading.

This is a moisture meter, an innovation of Dr Isaiah Muchilwa, a lecturer at the department of electrical and communications engineering at Moi University.

“I came up with the gadget to assist grain growers curb post-harvest losses,” says Dr Muchilwa at a grocery store in Eldoret, where Seeds of Gold found him showing traders how to use it.

It has taken him years of research and back and forth to perfect the gadget that he has dubbed Mootle.

“This machine monitors the level of moisture or humidity in dried grains such as maize and rice, oil seeds, legumes like beans, vegetables, fruits and even dried fish and omena,” he says, adding that it also checks whether honey is adulterated. The ‘digital clock’ attached onto the lid is the sensor.


“You open the lid and put the grains or vegetables inside. The sensor checks humidity and the temperatures on a scale of 50 to 100 per cent. If the reading goes above 70 per cent, then the grain has excess moisture and requires to be dried further to prevent growth of aflatoxin-causing fungi,” he offers.

The device, Dr Muchilwa says, is powered by small batteries that are locally available.


According to him, most farmers rely on the sun to dry their maize yet being in the tropics makes the country receive a lot of rains.

“This poses challenges when it comes to drying and consequently storage of the grain. Without a reliable way of knowing if the grain has low moisture, some farmers shake the dry grains to check if they are brittle while others chew them, but this not accurate.”

When it is rainy or humid, he explains, the grains can be exposed to high levels of moisture for longer periods, which favours mould infestation.

“This in turn changes the colour of the grain and the taste and lowers the quality of the grains. The moulds, which are fungi, release chemicals that result in aflatoxin, which has been linked to some of types of cancer,” he offers.

According to him, any reading below 70 per cent is perfect. “But if the gadget shows a reading of over 80 per cent, this means the grain requires thorough drying, though such produce can be stored for two weeks before it develops moulds,” he says.

Grain with 70 per cent moisture can be stored for six months while that below 60 per cent for over one year, according to the expert.

“Moulds normally need two to three weeks of mishandling to end up with aflatoxin,” he explains.

“ We need farmers to have this gadget at the farm level to prevent contamination,” says 44-year-old researcher.

He noted that the gadget comes in different sizes and will be selling at Sh1,000 once commercialisation begins.


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Quality grain

  • For the gadgets in the market, metering requires that farmers or traders pay Sh4,000 for calibration every year.
  • His machine can stay for over five years as long as one keeps it away from water.
  • At NCPB, the required moisture content level is 13.50 but on his machine, the moisture content should be at 65 per cent.