Managing Aflatoxins with Aflasafe® - Part of combined Integrated Pest Management Training
1. Managing Aflatoxins with Aflasafe®
Part of combined Integrated Pest Management Training
By: Titilayo Falade, Karim Dagno, Alejandro Ortega-Beltran
At IER-Mali, 16 August to 20 August 2021
2. Outline
• Current practices and identified gaps related to aflatoxin
management
• Proposed good practices for aflatoxin management
• Training modules
• Module 1: Introduction to aflatoxins
• Module 2: Good pre-harvest practices
• Module 3: Introduction to Aflasafe
• Module 4: Application of Aflasafe
• Module 5: Good harvest and post-harvest practices
• Results demonstrating efficacy of Aflasafe
3. Current practices and identified gaps related to aflatoxin management
• Incidence of aflatoxins in maize, sorghum and groundnut was high
• There was no structured arrangement for aflatoxin management in
practice
• Drying was done on the bare soil surfaces
• Field management was not optimal for aflatoxin control
• Aflatoxin biocontrol methods were not being used
• Aflatoxin testing using rapid testing equipment was being practiced
Mean: 1.8 ± 5.5 ppb
Range: <LOD – 35 ppb
Mean: 98.2 ± 253 ppb
Range: <LOD – 1245 ppb
Mean: 84.9 ± 317 ppb
Range: <LOD – 2076 ppb
Drying on bare surfaces in practice
Aflatoxin concentration
and fungal load in
sampled grains
4. Proposed good practices for aflatoxin management
• Follow good practices, using Aflasafe as a centerpiece technology among others
Optimal
storage
Rapid grain
drying
Timely
harvest
Sorting and
processing
Awareness
Policies
Testing
Dietary
interventions
Market
development
Resistant
varieties
Insect
control
5. Training modules
• Module 1: Introduction to aflatoxins
• Module 2: Good pre-harvest practices
• Module 3: Introduction to Aflasafe
• Module 4: Application of Aflasafe
• Module 5: Good harvest and post-harvest practices
6. Module 1 – What are aflatoxins?
Nature of aflatoxins and regulation
• Aflatoxins are natural toxins produced by some members of Aspergillus
species including A. flavus, A. parasiticus
• Aflatoxins are chemicals that cannot be perceived with the natural senses of
taste, smell, touch or sight
• There are four major groups of aflatoxins: Aflatoxins B1, B2, G1 and G2
• Due to the harmful effects of aflatoxins, total aflatoxins are regulated at 4 ppb
(in the EU) and 20 ppb (in many countries incl. the USA)
Routes of exposure
• Dietary exposure to aflatoxins is the commonest and causes a range of
illnesses including liver cancer, kidney toxicity and is associated with growth
retardation and immunosuppression
• Occupational exposure can also occur through the skin, but this is rare
Aspergillus
7. Module 1 – What are aflatoxins?
How does aflatoxin contamination occur?
• Aflatoxin contamination starts in the field when the toxin-producing genotypes
that occur naturally become associated with the crop
• Propagules of aflatoxin-producing fungi are air-borne and in the soil and crops
contact them through these media
• Aflatoxin contamination can also occur during harvest and post-harvest when the
crops are exposed to toxin-producers in the soil or in the environment
• Under conditions of stress and ideal conditions of temperature and moisture, the
fungus biosynthesizes aflatoxins within the crop
Through the pegs On the grains
Through the silk
8. Module 2 – Good pre-harvest practices to prevent aflatoxin exposure
• Prepare fields by ploughing and/or harrowing to a depth of 20 – 30 cm to control weeds,
kill some insects and for ease of incorporation of manure and seed planting
• Space crops properly (maize: 75 cm between rows, 25 cm within rows, and 5 cm deep;
groundnut: 75 cm between rows, 20 cm within rows and 6 cm deep)
• Weed fields at 1 to 3-weeks and 5 to 6-weeks post emergence, for groundnut also weed
during earthing up of ridges to encourage pegging. Uproot weeds to prevent re-growth
• Use recommended doses of fertilizers
• Manage pests using appropriate methods (incl. crop rotation, inter-cropping with non-
host plants, avoiding late planting to escape high pest densities
Prepare field and space properly Avoid pest damage
9. Module 3 – Introduction to Aflasafe
• Aflasafe is a biological control product that protects crops from exposure to high
densities of aflatoxin-producing fungi and so reduces exposure to aflatoxins
• Aflasafe is made of up highly-competitive non-aflatoxin-producing strains of
A. flavus selected from strains that occur naturally in the environment as active
ingredient
• The active ingredient spores are coated onto dead sorghum grains as carrier and
applied for field protection against aflatoxigenic strains with carry-over
protection at harvest and post harvest because of their association with the crop
10. Module 4 – Application of Aflasafe
• Aflasafe is applied during the crop
development between 2 and 3 weeks before
crop flowering: before the emergence of the
flag leaf (for maize and sorghum) and before
peg formation (for groundnut: between 30 and
45 days after planting)
• After applying Aflasafe do not conduct
activities that can bury the grains such as
weeding, trampling. Also, do not use chemicals
such as fungicides that can kill the active
ingredient until after 2 weeks after Aflasafe
application.
Sporulating
Aflasafe
Application rate of Aflasafe
is 10 kg/ha (i.e., 4 kg/acre)
Aflasafe is to be applied when the field is moist (e.g., just after rains or just
before rains) to allow sporulation of active ingredient to occur and protect
the crop from spores of aflatoxin-producers
11. Example for maize
Estimated Aflasafe application dates based on flowering dates after planting for maize
Extra early Early
Late-
intermediate
Late
45-50 DAP 51-55 DAP 56-60 DAP 55-63 DAP
Maize varieties
Estimated
Flowering date
after planting
24-36 DAP 30-41 DAP 35-46 DAP 34-49 DAP
Aflasafe
application
(2-3 weeks before
flowering)
For maize, estimated crop
height is between waist to
chest high for a person of
average height
12. Module 5 – Good harvest and post harvest practices
Harvesting
• Harvest on time when grains have reached maturity. Late
harvesting can pre-dispose crops to contamination
• Carefully harvest and avoid damage to the grains
• Shake off the excess dirt to reduce moisture and exposure to
contaminants
• Harvest the crops into clean containers and sort the damaged and
mouldy grains from grains that appear wholesome
Threshing
• Thresh grains onto clean covered surfaces such as onto tarpaulin
sheets
• Be careful not to damage/crush grains during threshing
Drying
• Dry grains rapidly on clean surfaces to moisture content below
14%
Separate damaged and undamaged crops
Image
credit: WFP
Light processing emoves dust and non-
food particles that can harbor
aflatoxigenic fungi
13. Module 5 – Good harvest and post harvest practices
Storage
• Ensure that storage facilities are clean, and store grains within clean bags. If bags are re-used, they
must be properly sanitized, dried, and without damage
• Use hermetic storage for properly-dried grains where possible to prevent insect damage and keep
moisture out
• Fumigate storage facilities against insect pests and rodents that damage grains and create entry points
for toxigenic fungi
• Store grains in well-ventilated areas on pallets to allow good airflow and prevent moisture
accumulation (i.e., keep away from direct contact with the walls and the floor)
• Do not combine new and old stock together in the store
Transportation
• Transport grains in clean, covered trucks or vehicles with pallets
Grains in well-aerated area on pallets
Triple-layer hermetic
(PICS) bags
14. Results from Mali fields (2019/2020) demonstrating efficacy of Aflasafe
Control
AflasafeSN01-
Treated
AflasafeBF01-
Treated
Groundnut 38.88 1.70
Maize 22.45 2.48 2.20
Sorghum 5.32 3.07 1.87
0
10
20
30
40
50
Mean
aflatoxin
concentration
(ppb)
Aflatoxin concentration of crops sampled from Aflasafe-
treated and control fields
15. 2.5
18.1
2.5
4.3
2.5
15.2
2.2
3.3
0
5
10
15
20
Treated Control Treated Control Treated Control Treated Control
Sikasso Segou Koulikoro Kayes
Mean
aflatoxin
concentration
in
ppb
Mean aflatoxin concentrations from sorghum fields
2.5
110.4
2.3
52.8
4
34.8
0
20
40
60
80
100
120
Treated Control Treated Control Treated Control
Sikasso Koulikoro Kayes
Mean
aflatoxin
concentration
in
ppb
Mean aflatoxin concentrations from groundnut fields
28.2
0
5
10
15
20
25
30
Treated Control Treated Control Treated Control Treated Control
Sikasso Segou Koulikoro Kayes
Maize
Mean
aflatoxin
concentration
in
ppb
Mean aflatoxin concentrations from maize fields
Results from Mali fields
(2020/2021) demonstrating efficacy
of Aflasafe (cont’d)
16. Summary
• Current practices and identified gaps related to aflatoxin
management
• Proposed good practices for aflatoxin management
• Training modules
• Module 1: Introduction to aflatoxins
• Module 2: Good pre-harvest practices
• Module 3: Introduction to Aflasafe
• Module 4: Application of Aflasafe
• Module 5: Good harvest and post-harvest practices
• Results demonstrating efficacy of Aflasafe
