Nelson Opoku and Vivian Hoffmann WEBINAR Catalyzing the Use of Aflatoxin Control Technologies in Kenya and Ghana NOV 26, 2019 - 09:00 AM TO 11:00 AM EST

1. Post-harvest solutions for
aflatoxin control
Nelson Opoku
University for Development Studies (Ghana)
Vivian Hoffmann
International Food Policy Research Institute (IFPRI)
November 26, 2019

2. Outline
• Post-harvest handling and aflatoxin
• Evidence from Ghana and Kenya on impact
and farmer use of improved practices
• Cost-effectiveness comparisons

3. Post-harvest handling & aflatoxin
• Aspergillus fungus:
– Is endemic in soils
– Requires moisture to grow
• Can be reduced by:
– Preventing contact between harvested crop & soil
– Speeding up the drying process
– Removing moldy grains or nuts prior to storage
– Keeping stored crops dry

4. Drying with heat reduces aflatoxin
Source: Kaaya & Kyamuhangire, 2010
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6
ppbaflatoxin
Months in storage (using typical polypro bags)
bare-ground dried hot-air dried

5. Better storage reduces aflatoxin
Source: Walker et al., 2018

6. 2 studies: Ghana (g’nut), Kenya (maize)
• What prevents use of good post-harvest
practices?
– Information? Incentives? Cost?
• Can training + provision of simple
technologies reduce aflatoxin?

7. • Timely harvest
• Promptly remove
harvested groundnuts
from field
• Do not leave nuts
heaped on vine in
field
Recommended harvest practices

8. • Ensure crop is fully dry before storing
• Dry on clean impermeable surface
– Protects crop from contact with soil
– Speeds drying
Recommended drying practices

9. • Remove bad nuts (moldy, broken, shriveled,
with holes) and maize cobs (moldy, rotten)
– Before drying
– Before storage
– Before consuming
– Bury out-sorts (do not use for soup, kulikuli, feed)
Recommended sorting practices

10. • Use new or cleaned bags
• Treat storage area with pesticide
• Store on raised pallets away from walls to
improve airflow
Recommended storage practices

11. Post-harvest practices of smallholders are
generally poor
Baseline practices in two samples
Ghana
(groundnut)
Kenya
(maize)
Area cultivated (acres) 1.9 1
Production (standard bags) 5.8 6.1
Dried on impermeable surface 0.01 0.03
Sort prior to storage 0.16 0.37
Store in hermetic bags 0 0.02

12. • Many farmers, consumers, and traders do not
know about aflatoxin or how to prevent it
• Small scale of production and low farmer
income may make prevention investments
unaffordable
• Premium prices for safer crops do not pass
through to producers
Why so little prevention?

13. Randomized controlled trial to test the impact of
1. Information on aflatoxin prevention
2. Information + Free drying tarps provision
3. Information + Price premium for low aflatoxin
nuts
on farmer practices and aflatoxin levels
• 1000 farmers in 40 villages in Northern and UE
• Randomized interventions within-village
Ghana study

14. Training by extension agents

15. • Tarps provided based on projected production
(1 tarp per bag up to 6 bags)
• Explained tarps were not to be sold, given
away, or used for other purposes
Tarp provision

16. Year 1
• Offered 15% over market price if nuts met aflatoxin standard
• Buyer came 2-3 months after harvest, later if requested
• Reminded of buyer visit after harvest
• Nuts tested at farmer’s home
• Only 5% of farmers contacted premium buyer; 1% sold
Year 2 changes
• Flat 25 GH₵ per bag (~25% value at harvest)
• Flexible time of sale
• 32% of premium group contacted buyer; 19% sold
Price premium

17. Outcomes measured over 2 years
• Year 1:
– Harvest & post-harvest practices
– Aflatoxin
• Year 2:
– All farmers given information
– Aflatoxin only
– Impacts are relative to providing information

18. All interventions improved practices

19. And observed tarp ownership
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Control Info only Tarps Price
premium
*
* *
* Indicates statistically significant difference relative to control group
* Indicates statistically significant difference relative to information only group

20. Giving drying sheets reduces aflatoxin by
50% relative to info only (Year 2)
0
1
2
3
4
5
6
Info only Tarps Price
premium
*
* Indicates difference aflatoxin level is significantly different from info only group
In year 1, aflatoxin too low (2.8 ppb for info only group) to see any impact

21. Kenya study
• 30 villages: 15 intervention, 15 control
• In intervention villages:
– provided training
– offered a range of technologies:
• Drying sheets
• Mobile drying machine
• PICS storage bags (after maize was dried)

22. Drying technologies
500-guage plastic sheeting
• Provided free of charge to
all meeting attendees in
treatment villages
EasyDryM500 mobile maize dryer (varied cost)
• Anticipated full cost (350 Ksh/bag) – 25%
• Partial subsidy (150 KSh) – 25%
• 100% subsidy (free) – 50%

23. Impacts on aflatoxin
0
2
4
6
8
10
12
14
16
18
20
Control
(N=98)
Treatment (all)
(N=73)
Treatment &
Used only drying
sheet (N=28)
Treatment & used
mobile dryer
(N=15)
* Indicates statistically significant difference relative to control group (Pretari et al., 2019)

24. Efficacy of technologies
Based on results from at least two studies per technology

25. Cost-effectiveness (Kenya)

26. Cost-effectiveness (Ghana)

27. Conclusions
• Improving post-harvest handling reduces aflatoxin
in maize and groundnut
– When yields are low, more cost-effective than pre-
harvest biocontrol
– Drying technologies are easy to use
(biocontrol sensitive to timing, hermetic bags to moisture)
• Some technologies have benefits beyond aflatoxin
– Farmers dry crops anyway; drying sheets and machines
can make this easier and faster
– Hermetic bags decrease post-harvest insect losses
– These more obvious benefits can increase usage

28. Encouraging technology use
through incentives & subsidies
Vivian Hoffmann
International Food Policy Research Institute (IFPRI)
November 26, 2019

29. Various studies show subsidies are effective
0 10 20 30 40 50 60
Biocontrol
(5.5 GH₵ / 100 KSh per KG)
Drying sheets
(10 GH₵ / 250 KSh each)
Mobile dryer
(9.2 Gp / 1.7 KSh per KG)
% of maize to which technology was applied
Farmer pays Free to farmer
Not offered for free

30. Good and bad news about subsidies
• Subsidies increase of control technologies by
smallholders better than any other strategy
• Subsidies do not discourage future demand
– Let farmers learn about a new technology
– Free hermetic bags increased later purchase (Omotilewa et al.,
2019)
• Subsidies may not be sufficient
– Good practices require effort as well as materials
– Building farmer awareness is critical
– For market producers, financial incentive also necessary

31. Role of price incentives
• Give producers a reason to invest in safety of crops
produced for market
Hoffmann and Jones, IFPRI Working Paper, 2018

32. Price incentives: Challenges
• Difficult to make attractive to small farmers
– Ghana study: few farmers sold for 15% premium with
inflexible timing
– 25% premium worked better, but above what market bears
– Flexible timing of offer costly to implement
• In high-aflatoxin areas, yield is often low & uncertain
– Three years in Eastern Kenya, struggled to purchase
significant volumes from farmers despite premium price

33. Even so, price incentives can help
• 5% incentive for safe maize (50% of 152 farmer groups, Kenya)
• Farmers treated maize primarily for their own consumption
• Incentive increased purchase among those already buying
– If poor harvest, enough good maize; if excess, good market
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Purchased any Acres covered
Proportionoffarmers
Aflasafe Purchases
No premium 5% premium

34. When commercial motivation drives
aflatoxin control
• When health concerns not well known, commercial
motivation is primary reason for aflatoxin control
– Nigeria study found only 13% of farmers’ household supply
of maize treated with Aflasafe (Narayan et al., 2019)
• To ensure farm families benefit, educate on health
benefits of aflatoxin control
– Include those who prepare food (usually women)
– Don’t rely solely on commercial partners for this role, but
work with them

35. Conclusions
Strategies to increase use of aflatoxin control strategies
by farmers
1. Make technologies available and affordable through subsidies,
targeting high-risk areas
2. Encourage premium prices through direct links between
farmers and aflatoxin-sensitive markets
3. Ensure farmers involved in premium markets are aware of
health benefits
None of these alone will solve the problem, but all have a
role to play

36. Thank you