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Simple grain sorting technologies for implementation at local maize mills

We will work together to test and improve simple grain sorting technologies to reduce mycotoxin exposure in eastern and southern Africa.

Photo of Rebecca NELSON
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EXPLAIN YOUR IDEA

Fungal toxins contaminate much of the food supply. Aflatoxin and fumonisin are carcinogenic and stunt growth, and are pervasive in the maize-based food system of eastern and southern Africa. Maize samples are highly heterogeneous, with most of the toxin being present in a few highly-contaminated kernels. Sorting grain based on density and spectral properties can allow people to reduce their exposure to mycotoxins. We have devised a couple of prototype grain sorters that use blowers to remove the lighter and more toxic grains. Initial tests in the US and Kenya have indicated potential, but we need to improve the design and performance and adapt a sorter to local hammer mills in Kenya and Tanzania.

WHO BENEFITS?

~70% of people in eastern and southern Africa process their maize (corn for ugali) in local hammer mills, known as posho mills.

WHERE WILL YOUR IDEA BE IMPLEMENTED?

Kenya and Tanzania

ARE YOU IMPLEMENTING IN AN ELIGIBLE COUNTRY?

  • Yes

EXPERTISE IN SECTOR

  • I’ve worked in a sector related to my idea for over a year

EXPERIENCE IN IMPLEMENTATION COUNTRY(IES)

  • Yes, for more than one year.

TELL US MORE ABOUT YOU!

Rebecca Nelson, Cornell University. Francis Ngure and Samuel Mutiga, Biosciences eastern and central Africa and Cornell. Neema Kasim and Martin Kimanya, Nelson Mandela African Institute for Science and Technology.

Maize is the mainstay of the diet for millions of people in eastern and southern Africa.  Unfortunately, maize (corn) is often colonized by tiny fungi that produce toxins that stunt growth, reduce immunity to diseases and cause cancer.  It should be possible to reduce toxin exposure by sorting out the toxic kernels of maize at the neighborhood maize mills where most people grind their maize  before cooking it into stiff porridge (ugali or similar).  Our initial prototype sorters work pretty well, but we want to improve them by working with local innovators and millers.

8 comments

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Spam
Photo of William Lanier
Team

To help the shortlisted ideas become the best that they can be…
Sun and heat will stop fungi, but the colorless aflatoxin that remains is extremely difficult and costly to sort from surplus grain. 
Agronomists know that in environments like Northern Ghana which couple naturally moving air of low relative humidity and the heating effects of sunshine, grain will dry standing. When grain is dried standing, it spends less time close to the ground exposed to the soil-borne fungi that produce aflatoxin. However those operations that are too small or not conscious of quality, harvest grain with little regard for moisture content onto drying tarpaulin or platforms that are at ground level. Additional handling and drying grain close to the ground increases the risk of soil borne fungi that produce aflatoxin and other pests.
Some production packages have tested solar, bio-mass fueled dryers and even grain sorters to enhance typical storage outside the zones where grain dries standing. However, after support ends closing the yield gap means “Small-scale farmers require solar dryers that are more affordable to purchase or construct and need little maintenance” and “lack of success of using solar based drying among rural commercial [surplus] farmers has been attributed to the cost, complicated operational procedures, and the reluctance to change from traditional methods (IRAC, 2015)” not to mention the additional costs of maintaining the calibration of density and spectral and blowing sorters.
Combining utility with wheels creates cost-effective storage that: when empty, moves to scale for demand, weather, crop pests or PHL; let’s transport go to haul heavy loads (Bessonova, 2015); facilitates processing for market opportunities to reduce the yield gap optimally.
Is sorting grains after they are contaminated a less than an optimal approach to addressing the source of the problem?
William
NeverIdle mobile utility storage
Jobs for Youth to Reverse PHL 

Spam
Photo of Rebecca NELSON
Team

Thank you for those comments, Isaiah.  I just returned from Kenya last night.  I agree that it would be great if we can help protect the safety of each crop/product, at each step along the value chain.  My thinking is that if we can raise awareness by providing access to citizen monitoring  at the end of a key value chain (maize, the #1 staple), then people will be better at taking care of the issues along the way, and with their other foods.  That is, maize consumers will start noticing the issues, and this will drive concern for quality along the process, since they will demand clean food to each.  We could encourage and support sorting with displays that raise awareness of the full diversity of issues, such as those that you raise. 

Regarding cost: our current blower costs ~$120, and the sorter itself is probably around the same cost.  We're still actively working on designs and options.  Maybe we can come up with a gravity table that's powered by the posho mill itself (using a belt from the same motor) to reduce the additional cost to the miller for establishing the technology.  Suggestions welcome, of course!

Many thanks again, Rebecca

Spam
Photo of Isaiah Etemo Muchilwa
Team

...Great response, thanks and all the best.

Spam
Photo of Isaiah Etemo Muchilwa
Team

Hi Rebecca, thank you for this initiative to reduce aflatoxin contamination levels in maize, our staple food in Kenya. I like the fact that your proposed intervention is targeting local posho mills and I foresee some success given that these mills are used by many both in towns and rural villages. A few queries for you...
Do you have any preliminary indications of the cost of this intervention and time it takes to process say 1 kilo of grain? How do you intend to treat the significant portion of maize that is consumed whole in homes, without going through posho mills? Githeri, for example, is a popular meal comprising pre-boiled maize and dried beans, that is taken mainly for breakfast and lunch in many homes and constitutes many school feeding programmes across the country. Dried beans too have been associated with mycotoxins / aflatoxins and the challenge is, say we succeed in tackling the maize problem - what happens to the beans? Can your proposed solution be applied to dried beans too? Many still think that removing foreign objects and washing off soil (the main sources of fungal contaminants) from foods that have been stored for months in this condition make them safe to eat, as you will see in this video (link appended). Nobody is testing for fungal toxins and hence no motivation to control. Employing blowers to remove smaller (diseased and broken) kernels is an excellent strategy against aflatoxins, but why wait to implement this late at the posho mill, rather than early-before grains are bagged for storage, as a preventive measure?...just food for thought, otherwise great job!

https://www.youtube.com/watch?v=FpEX5v5ltdg

http://ijat-aatsea.com/pdf/v9_n1_13_January/14_IJAT_2013_9(1)_Embaby,%20E.M-%20Plant%20Pathology-must%20revised%20X.pdf

Spam
Photo of Rebecca NELSON
Team

Thanks for your comment, William.  I agree that mycotoxins should be managed as well as possible across the entire value chain.  For many people in SSA, the value chain is pretty short: from the farm to the local hammer mill and then the cooking pot (sometimes with local trade in between).  People bring small amounts of grain (typically 2-9 kg) to their local hammer mill to process the week's food. So there's not too much storage time after the sorting and milling that we propose.

Spam
Photo of William Lanier
Team

Hello Rebecca and Simple Grain Sorting,
If we accept that SSA grains will continue to contain afaltoxin, grain sorting will be a good way to improve the high calorie grain that feeds most of the human labor and animal power needed to grow, harvest and process densely nutritious, fruits and vegetables.


However, once grain is sorted where will it be stored against aflatoxin?

Plastic bags do not stop chewing rats or insects that bore in or “perforations” (George, 2011) caused by handling and soon it needs recycling.
Artisan constructed airtight metal cans are fragile and difficult to transport to reduce pests at harvest or scale for net benefit at markets. And any airtight storage system needs well maintained GDLI to stop the condensation (caused by day and night temperatures) that let low levels of fungi and insects produce more aflatoxin,

The team Mobile utility storage team would like to read your comments at
<https://challenges.openideo.com/challenge/agricultural-innovation/ideas/storage-to-reverse-grain-postharvest-loss> .

William

Spam
Photo of Rebecca NELSON
Team

Thanks, Oz!  Yes and i just emailed you.  Would love to discuss.
Rebecca

Spam
Photo of Oz
Team

Hi Rebecca,
Have you researched sorting based on spectral properties?  Happy to discuss.  Thanks, Oz
oz@agroanalitix.com