importance of aflatoxin: summary of biocontrol projects in burkina faso
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Importance of Aflatoxin
Summary of Biocontrol Project in
Burkina Faso
Importance of Aflatoxin
Summary of Biocontrol Project in
Burkina Faso
Ranajit BandyopadhyayIITA, Ibadan, Nigeria
www.iita.org
• Highly toxic metabolite produced by the ubiquitous Aspergillus flavus fungus
• The fungus resides in soil and crop debris, infects crops and produces the toxin in the field and in stores
Aflatoxin Facts
• Contamination possible without visible signs of the fungus
• Fungus carried from field to store
Photo: Peter Cotty
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• Unlike most fungi, Aspergillus flavus is favoured by hot dry conditions.
• The optimum temperature for growth is 37 C, but the fungus readily grows between the temperatures of 25-42 C, and will grow at temperatures from 12-48C.
• Toxin contamination more when night temperatures are high
• Drought stress predisposes plants to aflatoxin
Disease Development & Weather
Source: www.aspergillusflavus.org
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Aflatoxin Contamination Occurs in Two Phases
Phase I: Before Crop Maturity Developing crops become infected. Associated with crop damage (insect, bird, stress). Favored by high temperature (night) and dry conditions.
Phase II: After Crop Maturity Aflatoxin increases in mature crop. Seed is vulnerable until consumed. Rain on the mature crop increases contamination. Associated with high humidity in the field & store, insect
damage, and improper crop storage or transportation.
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Pre‐Harvest Problem
Aflatoxin (ppb)ppb)
Peanut (n = 188) Maize (n = 241)
Distribution (% samples)
> 4 54 70> 10 41 52> 20 29 24
Descriptive statistics (ppb)
Minimum < LOD < LODMaximum 3487 838
Mean 111 33LOD = Limit of Detection; States sampled: Nassarawa, Katsina, Kaduna, Kano, Bauchi, Jigawa & Niger
Aflatoxin in Groundnut and Maize at Harvest, 2012, Nigeria
Increases in store
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Post‐Harvest Aflatoxin
Aflatoxin in Groundnut and Maize in Farmers’ Store in Burkina Faso
Crop Zone B‐aflatoxin (ppb)Mean Range
GroundnutSudan Savannah 46.0 0.0 – 925.0
Northern Guinea Savannah 11.3 0.0 – 41.0Southern Guinea Savannah 12.3 1.0 – 21.0
MaizeSudan Savannah 49.6 2.0 – 517.0
Northern Guinea Savannah 17.8 2.7 – 127.0Southern Guinea Savannah 7.0 0.0 – 11.7
Prevalence of Aflatoxins in Food & Feed
• Several African staple commodities affected• High human exposure in Africa – mother to baby• Levels and frequency of occurrence high• Concern for food and feed processors, government
and emergency food reserve agencies, school‐feeding
• Aflatoxins disproportionately impact the poor• Highly toxic strains, conducive environmental
conditions, traditional farming methods and improper grain drying and storage practices, unregulated markets
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Aflatoxin Contamination in West Africa
• Maize: 4,000 – Benin• Peanut: 925 – Burkina• Sorghum: 80 – Ghana• Rice: 372 – Nigeria• Millet: 200 – Nigeria• Tiger nuts: 120 – Nigeria
Primary products• Peanut paste: 3,278 – Ghana• Peanut sauce: 943 – Ghana• Leaf sauce: 775 – Gambia• Maize dough: 313 – Ghana• Kenkey: 524 – Ghana• Cashew paste: 366 – Ghana• Peanut oil: 500 – Nigeria• Yam flour: 7,600 – Nigeria• Local beer: 135 – Nigeria• Infant food: 19* – Burkina
Food productsMTL = 10 - 20 ng/g
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Aflatoxin and Human Health
Death Binds with DNA -- mutagenic Type I carcinogen Causes liver cancer – increasing incidence Aflatoxin interacts with HBV
• 30 times more potent in HBV+ people• 5-60 times higher cancer risk• 40% of liver cancer cases linked to aflatoxin
Associated with stunting in children Associated with immune suppression Impede uptake and utilization of micronutrients in
human systems Associated with Kwashiorkor in children Contributes to 40% of DALYs
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Animal Health Impact of Aflatoxin
Livestock and poultry losses liver damage including cancer recurrent infection due to
immune system suppression reduced growth rate losses in feed efficiency decreased milk and egg yield embryo toxicity (reduced
reproductivity) death (cattle, turkey, poultry,
swine..)
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Aflatoxin and Poultry (Broilers)
Aflatoxin levels in feeds in Nigeria
Aflatoxin level (ppb) Samples (%)
<20 (safe) 38
>20 to 100 (up to 5x) 14
>100 to 500 (up to 25x) 41
>500 to 1,000 (up to 100x) 7
AF-free diet 500 ppb AF dietAF-freediet
500 ppb AF diet
~40% reduction in live weight (8 weeks)
EC 2007
Aflatoxin and Trade
SOURCE: EU Rapid Alert System For Food and Feed (RASFF, 2005)
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Trade Losses due to Aflatoxins
• Nigeria and Senegal major groundnut exporters in 1960s. Compliance has economic incentives
• Senegal: US$ 4.1 million added capital investment and 15% recurring cost would attract 30% price differential to oil cake.
• Export would increase from 25K tons to 210K tons.
• Increased export volume and price differential would annually add $281 million value to groundnut export for the capital investment.
• For confectionary groundnut, adherence to Good Management Practices would increase export value by US$ 45 million annually.
• Best quality exported; poorer quality consumed domestically. Peanut
Maize
Coffee
Cocoa
Groundnut Pyramids in Nigeria during 1960sPyramids in Egypt?
World Bank; Mbaye (2004)
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Mycotoxin Projects in Burkina Faso
• 2007‐2010: Diffusion of cost‐effective technologies for the control of mycotoxin contamination for increased health and income in Burkina Faso, Tanzania and Mozambique
• 2010‐2014: Biological Control of Aflatoxins in Maize for Enhanced Food Safety and Income in Burkina Faso
Two projects – both funded by Austrian Development Cooperation
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Biocontrol Project Outputs
• Output 1: Aflatoxin biocontrol strains identified for reduction of aflatoxins in maize and other associated susceptible crops.
• Output 2: Efficacy and product data available for pre‐registration of atoxigenic strains as biopesticides.
• Output 3: Students and staff trained for conducting aflatoxin research.
• Output 4: Infrastructure and technical capacity developed for aflatoxin research.
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Atoxigenic Strain IdentificationCollection/characterization Toxin assay
Fieldefficacy
test
Labcompetitionassay
VCG/DNA characterization
cnxnia-D
Unknown 2
+
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1. Strain Identification
• 3,660 Aspergillus isolates from 256 samples collected in three agro‐ecological zones of Burkina Faso.
• Four widely distributed and adapted atoxigenic strains, namely M109‐2, M110‐7, MO11‐8 and GO18‐2 identified.
• Biocontrol product Aflasafe BF01 constituted with the four strains mentioned above
Broadcast @ 10 kg/ha 2‐3 weeks before flowering
Sporulation on moist soil
Spores
Insects
Aflasafe in 2.5 & 5 kg bags
3‐20 days
Wind
Soilcolonization
30‐33 grains m‐2
How Does aflasafe Work?
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Crop Sample Treatment FieldsAF
mean (ppb)*
Red uction(%)
Groundnut
HarvestTreated 51 3.7
92Control 51 44.0
StorageTreated 49 15.0
86Control 49 101.0
Maize
HarvestTreated 17 1.7
82Control 17 9.1
StorageTreated 17 50.3
84Control 17 319.0
*All means of aflasafe treated and control pairs significantly different; Student’s t-test (P<0.05)
Efficacy trial sites
Crop sampling sites
2. Efficacy of Aflasafe BF012012
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3. Student/Staff Training
• An INERA staff (Mr. Touré Mahama)was trained in principles and methodologies followed in aflatoxin biocontrol research at IITA.
• Spent three months each for two years at IITA.
• MPhil student Mrs TIENDREBEOGO Assiata spent four months at IFA‐Tulln, Austria
• She worked on development of DNA‐based assays to monitor Aspergillus biocontrol strains in the field.
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4. Infrastructure Development
• A lab renovated in INERA’s Farako Ba research station
• Lab equipped with Laminar flow hood, Autoclave, Coffee grinder, Water‐jacket incubator, Digital shaker, Neogen aflatoxin kits and LFD reader, and automatic pipettes
• The renovation of the building and the new equipment facilitated further research activities after the project ended
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Next Steps
• A highly effective biocontrol product available • Disseminate Full registration of the product
necessary• Developed in partnership with farmers to
demonstrate product efficacy• Need for consultation with other stakeholders in
maize and groundnut value chains• Explore mechanisms for scaling up of the product –
public, private, mixed• Identify scaling up partners• Plan scaling up implementation
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Aflasafe Manufacturing Facility
Large‐scale: capacity 5 tons/hour
CoolerRoaster
Inoculum Production Lab
Big WeigherSmall Weigher
Sealer Sealer
Sterilised Grain Silos50 tons each
Raw Grain Silo100 tons
Finished Product
Debearder
Fine Cleaner
Deabearder & Fine CleanerHousing
IntakePit
Roaster & Coolerhousing
2 Labs
IITA
TucsonUSDA/ARS
IITA, USDA, & Doreo have Teamed up to Bring Aflatoxin Prevention to Africa
Made Possible by Many National Partners in Ministries, Industry, and on the Farm
Nigeria
For more information about aflatoxin biocontrol for Africa, check out: www.aflasafe.com