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Biocontrol of Aflatoxin in Kenya, R. Bandyopadhyay et al.


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Presentation at the Aflacontrol Conference on Aflatoxins, Food Safety and Food Security, IFPRI & ACDI/VOCA Kenya Nairobi, Kenya, January 13th 2011

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Biocontrol of Aflatoxin in Kenya, R. Bandyopadhyay et al.

  1. 1. Source: Environmental Health Perspectives Aflatoxin Biocontrol Ranajit Bandyopadhyay IITA Peter Cotty USDA-ARS Charity Mutegi KARI Claudia Probst Univ of Arizona Joseph Atehnkeng IITA Jacob Mignouna AATF Francis Nangayo AATF Margaret McDaniel USDA-FAS
  2. 2. <ul><li>Background </li></ul><ul><li>Biocontrol principles </li></ul><ul><li>Strain identification </li></ul><ul><li>Experiences in Nigeria </li></ul><ul><li>Biocontrol initiative in Kenya </li></ul><ul><li>Summary </li></ul>Outline Source: Environmental Health Perspectives
  3. 3. Aflatoxin: What is it? <ul><li>Highly toxic metabolite produced by the ubiquitous Aspergillus flavus fungus </li></ul><ul><li>The fungus infects crops and produces the toxin in the field and in stores </li></ul><ul><li>Fungus carried from field to store </li></ul><ul><li>Contamination possible without </li></ul><ul><li>visible signs of the fungus </li></ul><ul><li>Some predisposing factors: </li></ul><ul><ul><li>pre-harvest high temp & drought stress </li></ul></ul><ul><ul><li>wet conditions at harvest and </li></ul></ul><ul><ul><li>post-harvest periods </li></ul></ul><ul><ul><li>insect damage </li></ul></ul>
  4. 4. Bibiana Onemas Kikweo
  5. 5. Prevalence of Aflatoxins in Food & Feed <ul><li>Several African staple commodities affected </li></ul><ul><li>High human exposure in Africa – mother to baby </li></ul><ul><li>Levels and frequency of occurrence high </li></ul><ul><ul><li>>30% maize in stores with >20 ppb aflatoxin </li></ul></ul><ul><ul><li>~ 90% stores are contaminated with Afla fungi </li></ul></ul><ul><ul><li>Up to 40% grain in households with aflatoxin </li></ul></ul><ul><li>Concern for food and feed processors, government and emergency food reserve agencies </li></ul><ul><li>Highly toxic strains, conducive environmental conditions, traditional farming methods and improper grain drying and storage practices, unregulated markets </li></ul>
  6. 6. Mycotoxin R-4-D at IITA <ul><li>Aflatoxin and Child health </li></ul><ul><li>Breeding for resistance </li></ul><ul><li>Biocontrol through competitive exclusion </li></ul><ul><li>Low cost aflatoxin detection methods </li></ul><ul><li>Development and dissemination of integrated pre- and post-harvest aflatoxin management in value chain </li></ul><ul><li>Awareness , advocacy and information exchange </li></ul><ul><li>Ecology and biology of toxigenic fungi </li></ul><ul><li>Strengthening of surveillance and mycotoxin monitoring capacity </li></ul><ul><li>Standards & trade development related to aflatoxin </li></ul><ul><li>Coping with the impact of climate change on aflatoxin & human health </li></ul>
  7. 7. Biocontrol WORKS In tens of thousands of acres in the US! Aflasafe AF36 Aflaguard IT WORKS In Africa TOO!
  8. 8. Principles of Aflatoxin Biological Control <ul><li>Fungal communities differ in aflatoxin-producing ability & this influences crop vulnerability to contamination. </li></ul><ul><li>Some strains produce a lot (toxigenic), and others no aflatoxin (atoxigenic) </li></ul><ul><li>Competitive exclusion (one strain competing to exclude another) as biocontrol principle in practice in the US </li></ul><ul><li>Shift strain profile from toxigenic to atoxigenic </li></ul><ul><li>Thus, aflatoxin contamination reduced </li></ul>Incidence (%) T O X I G E N I C A T O X I G E N I C
  9. 9. Technology Development: Atoxigenic Strain Identification Collection/characterization VCG/DNA characterization Toxin assay Field Competition assays Lab cnx nia-D Unknown 2 + Field efficacy test
  10. 10. How does Biocontrol Work? Broadcast @ 10 kg/ha 2-3 weeks before flowering Sporulation on moist soil Spores Insects Inoculum on sorghum grain carrier 3-20 days Wind Soil colonization 30-33 grains m -2 Hyphal network in seed pericarp
  11. 11. Aflatoxin Biocontrol Facts Crops are infected by complex communities of diverse fungi Fungal communities differ in aflatoxin-producing ability & this influences crop vulnerability to contamination. Atoxigenic strains can be used to reduce aflatoxin-producing ability. There are many native atoxigenics Select safe strains best adapted to cropping systems, ecosystems, & climates Atoxigenics are Already Present on the Crop Just increase the frequency of endemic strains & natural interference with contamination Treatments May have Long-Term Influence & Cumulative Benefits More than One Crop May Benefit From the Applied Strain Atoxigenic Strains can be Applied Without Increasing Infection and without increasing the overall quantity of A. flavus on the crop & throughout the environment
  12. 12. Ex-Ante Impact Assessment of Aflatoxin Biocontrol in Nigeria <ul><li>DALYs saved: 103,000 to 184,000 </li></ul><ul><li>Cost-effectiveness ratio: 5.1 – 24.8 </li></ul><ul><li>Benefits are likely to be higher if all health impacts from aflatoxin exposure are considered. </li></ul>Wu & Khlangwiset (2010), Food Additives & Contaminants
  13. 13. <ul><li>National regulatory systems for commercial release of bio-pesticides must be addressed for significant impact </li></ul><ul><li>The nurturing of local enterprises to produce and market such biocontrol products is a significant challenge </li></ul>Challenges Partnerships and institutions key for meeting these challenges
  14. 14. Building Partnerships for Aflatoxin Biocontrol <ul><li>Registration of the atoxigenic strains as biopesticides </li></ul><ul><li>Sensitisation of growers, consumers, regulatory agencies and policy makers about potential of biocontrol </li></ul><ul><li>Upscaling and outscaling to wider areas ( Nigeria & Kenya – AATF, MycoRed) </li></ul>
  15. 15. Outline NAFDAC provisional registration approval letter
  16. 16. 10-kg boxes of AflaSafe ready for deployment
  17. 17. Explaining aflatoxin and biological control to farmers in their fields
  18. 18. B-Aflatoxin Concentration (ng/g) in Groundnut After Poor Storage *Mean of 4 samples ± SE Treatment B-aflatoxin* Reduction (%) Aflasafe TM 0.3 ± 0.4 96 Control 8.2 ± 2.5
  19. 19. Farmers treating maize and groundnut fields with AflaSafe Aflatoxin reduction at harvest: 2009: 80% 2010: 89% 56 to 73% carry-over of inoculum one year after application
  20. 20. Farmer Training
  21. 21. Training in Aflatoxin Assay <ul><li>BOKU collaboration; ADA funding </li></ul><ul><li>Participants: Farmers, technicians, grain storage personnel, processors </li></ul>Burkina Faso Mozambique
  22. 22. Awareness and Information Exchange <ul><li>More than 10 million people in Benin, Togo and Ghana are now aware of the dangers of aflatoxin-contaminated feed/foods. </li></ul>
  23. 23. Kenya KARI AATF IITA USDA-ARS USDA-FAS Ministry of Agriculture Partnership Strong support from Min Agri and KARI
  24. 24. <ul><ul><li>Increase technical capacity to manage contamination for both health improvement and increased crop value. </li></ul></ul><ul><ul><li>Test and implement biological control of aflatoxins throughout Kenya. </li></ul></ul><ul><ul><li>Develop simple procedures and controls to minimize human exposure to aflatoxins and ensure contaminated crops flow to high value alternative markets. </li></ul></ul><ul><ul><li>Develop low-cost capacity to analyze aflatoxins in markets, during crop off-take, and in storage. </li></ul></ul><ul><ul><li>Create awareness of aflatoxin influences on human and animal health and procedures to limit contamination and human consumption of aflatoxins. </li></ul></ul>Proposed Plan for Kenya: Mid- and Long-term
  25. 25. Genesis and Time Line <ul><li>2004 to 2006 </li></ul><ul><ul><li>Grain and soil samples collected by CDC, Ministry of Health and Icipe </li></ul></ul><ul><ul><li>Aspergillus population structure studied by Cotty lab in USDA-ARS and biological basis (S-strain) of high toxin production discovered </li></ul></ul><ul><li>2007 to 2010 : Several Kenyan atoxigenic strains identified by Claudia Probst, and 13 highly competitive atoxigenic VCGs selected based on laboratory studies </li></ul><ul><li>July 2010 : USDA-FAS provides funding for further exploring the utility of the atoxigenic strains in aflatoxin biocontrol in Kenya and training Kenyan staff and infrastructure development </li></ul><ul><li>Oct 2010 : AATF provides complementary funding to KARI and IITA </li></ul><ul><li>Sep-Nov 2010 : KSTCIE considers application for repatriation of Kenyan atoxigenic strains </li></ul><ul><li>Dec 2010 : KSTCIE approves strain repatriation, import permit issued, inoculum multiplied in IITA-Ibadan, shipped to Kenya </li></ul><ul><li>29 Dec 2010 : Field plots in KARI-Katumani inoculated with 13 atoxigenic strains </li></ul><ul><li>Further evaluation to be conducted in Kiboko, Bura and Tana in 2011. </li></ul><ul><li>Purpose: To identify 4-6 highly competitive strains under field conditions in Kenya and develop a biocontrol product </li></ul>
  26. 28. Atoxigenic Strain Identification in Kenya <ul><li>More than 3,400 A. flavus isolates recovered from 263 ground maize samples obtained between 2004 and 2006 from the Eastern, Coast and Rift Valley </li></ul><ul><li>290 L strain isolates screened for aflatoxin-producing ability on maize </li></ul><ul><li>96 identified as atoxigenic and co-inoculated with toxigenic stain on maize. </li></ul><ul><ul><li>Average aflatoxin reduction: 7 to 98% </li></ul></ul><ul><li>23 Strains that reduced >80% or members of VCG from 2 or more locations were further evaluated </li></ul><ul><ul><li>Aflatoxin reduction: 64 to 90% (mean 80%) </li></ul></ul><ul><li>12 atoxigenic VCGs (13 strains) selected for further evaluation under field conditions in Kenya </li></ul>
  27. 29. Aflatoxin in Maize Co-Inoculated with a Toxigenic Strain and a Few Kenyan Atoxigenic Strains Isolate co-inoculated Aflatoxin B1 (µg g -1 ) Average Reduction (%) Test 1 Test 2 Toxigenic alone 105 109 C6-E 9 19 87 C8-F 13 21 82 E62-L 8 23 87 E63-I 12 25 82 R1-N 12 25 83 NRRL-21882 9 27 86
  28. 30. Distribution of Kenyan Atoxigenic VCGs <ul><li>96 atoxigenic isolates belonged to 53 VCGs </li></ul><ul><li>41 VCGs have single member </li></ul><ul><li>7 multi-member VCGs in eastern province </li></ul><ul><li>4 in 2 provinces, and 1 in 3 provinces </li></ul>Samples = Number of samples the indicated VCG was isolated from. Total number of samples was 156. Isolates = Number of atoxigenic A. flavus isolates belonging to the indicated VCG.
  29. 31. Probst et al. 2011. Plant Disease. Vol. 95, January, 212-218
  30. 32. Inoculum at Nairobi airport being cleared by Charity Mutegi
  31. 33. Inoculum transported to KARI-Katumani
  32. 34. KARI-Katumani Center Director inspecting inoculum
  33. 35. Inoculum of 13 Kenyan atoxigenic strains in KARI-Katumani Lab
  34. 36. Soil sample collection before inoculation in KARI-Katumani
  35. 37. Training field workers in KARI-Katumani
  36. 38. Workers in protective clothing handling inoculum in KARI-Katumani
  37. 39. Inoculation in KARI-Katumani
  38. 40. Inoculation in KARI-Katumani
  39. 41. Focus Countries and Stages of Development Yet to start Partially started Completed Country Strain identification Partnerships Commercialization Capacity development Nigeria Senegal Burkina Faso Ghana Cote d’Ivoire Kenya Malawi Mozambique Tanzania Ethiopia Mali
  40. 42. Aflasafe-SN1 inoculum application in Senegal
  41. 43. Manufacturing Need for a pilot manufacturing facility Production Room Atoxigenic Strain Manufacturing Facility Arizona Cotton Research & Protection Council
  42. 44. How do we stimulate demand in the medium term?
  43. 45. Summary Partnership for Aflatoxin Control can improve health and income of people in developing nations <ul><li>Aflatoxins in food and feed pervasive in Africa </li></ul><ul><li>Biological control in conjunction with other management practices has potential to dramatically reduce aflatoxin contamination </li></ul><ul><li>Large scale manufacturing and commercialization of biocontrol agents a prerequisite for adoption. </li></ul><ul><li>Aflatoxin mitigation plan developed </li></ul><ul><li>Linkage being developed with other organizations for downstream dissemination activities for biocontrol </li></ul><ul><li>Support and partnership needed from national governments, donors, private food sector, farmer groups, and regulators to improve health and income of people </li></ul>
  44. 46. Thank you IITA Campus, Ibadan