Combating aflatoxins: Can we win the war?
4 likes1,537 views
The document addresses the challenge of aflatoxins, highlighting the health risks they pose to humans and livestock, as well as the economic impact and the need for effective intervention strategies. It outlines potential solutions, like good agricultural practices and feed standards, while emphasizing the importance of balancing regulations with economic burdens on farmers. The collaborative efforts among various organizations aim to reduce aflatoxin prevalence and mitigate its effects through research and stakeholder involvement.
Combating aflatoxins: Can we win the war?
- 1. Combating aflatoxins: Can we win the war? Johanna Lindahl and Delia Grace Nutrition working group platform Berlin, Germany 1 October 2014
- 2. The topic of today • What are the possible interventions and why are they not out there on full scale yet? • What research needs priority? • What does livestock have to do with it? • What harm can be done by interventions?
- 3. Aflatoxin work by CGIAR International Center for Tropical Agriculture (CIAT) International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) International Institute of Tropical Agriculture (IITA) International Livestock Research Institute (ILRI) International Maize and Wheat Improvement Center (CIMMYT) International Food Policy Research Institute (IFPRI)
- 4. What do we want to prevent? 1. Negative health effects in humans 2. Negative health effects in animals affecting livestock production (nutrition & poverty reduction) 3. Negative economic impacts 4. Negative publicity 5. Negative health effects in animals (animal welfare)
- 5. Need to fill the knowledge gaps 1. Documenting occurrence of aflatoxins 1. Maize 2. Groundnuts 3. Milk 4. Animal feed 5. Risk mapping 2. Exposure assessment in humans 3. Risk assessment (health impacts and likelihood)
- 6. Quick reminder-why is the toxin there? • Fungi (Aspergillus) infect crops pre-harvest, during harvest or during storage • If crops are stressed they are more susceptible • Especially susceptible crops: maize, groundnuts • Optimum temperature 37C (range 12-48) • Mainly tropical disease Photo by CIMMYT. Photo by IITA. Aspergillus naturally infected groundnuts in Mozambique.
- 7. Farmer Consumer Economic flow Aflatoxin flow Human exposure Feed producer AB1 AB1 AB1-> AM1 AM1 Corn/feed produced at farm Corn/feed purchased Milk produced at farm AB1 AM1 Treatments Feed seller Farmer Veterinary services Milk retailer Agricultural services Consumer
- 8. At what points can we make interventions? 1. Growing crops 2. Harvest 3. Storage 4. Before consumption 5. Mitigating the effects after consumption
- 9. Pre-harvest Prevent fungal growth pre-harvest: Insects and drought is predisposing 1. Breeding for resistance Drought-tolerant, or insect-resistant maize 2. Good agricultural practices Fertilizers, pesticides, irrigation 3. Biological control using atoxigenic strains Aflasafe, Afla-guard
- 10. Post harvest Poor storage conditions pre-disposing 1. Good agricultural practices Pest control 2. Improved drying technologies Improper drying of grains - Different grains being dried on roadside with rains looming in the horizon. Photo by IITA
- 11. Preventing consumption 1. Sorting 2. Legislation Limits for human and animal consumption 3. Treatment (detoxification) Ammoniation Ozone treatment Nixtamilization Fermentation Binders
- 12. Mitigating effects in the consumer Hepatitis B vaccination – Good effect!
- 13. Public awareness and dietary considerations Dietary diversification, switching from high-risk crop Consumption pattern Consumer awareness
- 14. The risks with uncertainty Do no harm! Interventions can not be allowed to increase risks of other hazards. Mycotoxin Main fungi Impact on animal health Aflatoxins Aspergillus spp All livestock susceptible to different degrees. Acute toxicity, hepatotoxic and nephrotoxic. Carcinogenic and mutagenic. Growth impairment. Immunosuppression. Ochratoxin A Aspergillus spp, Penicillum spp Nephrotoxic Immunosuppression Possibly carcinogenic Fumonisins Fusarium spp Toxic to liver and central nervous system Possibly carcinogenic Zearalenone Fusarium spp Swine highly sensitive, cattle less sensitive. Endocrine disruption. Estrogenic effects, reduced reproduction, feminisation, malformations. Trichotecenes Fusarium spp Gastrointestinal disturbance. Reduced feed intake. Ill-thrift. Immunosuppression.
- 15. Regulatory benefits must be balanced with regulatory burdens The economic cost of regulatory enforcement, testing and quality control is high. Furthermore, stringent regulatory enforcement is not always feasible. • In the USA, the annual cost of regulatory enforcement, testing and other quality control measures for aflatoxin is $0.5 billion USD annually. • Regulation costs 3.3% of the total value of corn produced. • In one study, a turkey farm used 2,200 tests for aflatoxins at a cost of $2.67 each for 400,000 tons of maize used as feed: • Testing costs 1.8% of the total value of the corn used. • The value of maize in East Africa was $3.4 billion USD in 2012. • This implies the cost of regulating aflatoxins would be a least $68 million USD )
- 16. The consequences of export barriers • The best products are exported • The bad products are left to the national markets Photo by IITA.
- 17. Problems moping up: What to do with contaminated crops?
- 18. What happens when we condemn the food? Developing country Relatively large food insecure population Large part of maize crop being contaminated with high levels of aflatoxins Control functions only in formal market chains Less alternative uses and lacking control of condemned products No control at informal markets increase the proportion of contaminated crops Visibly damaged crops may be fed to livestock, the rest becomes human food Population are more exposed to contaminated food, especially poor Large part of maize crop being contaminated with high levels of aflatoxins Control functions in the formal market chain and condemnation Alternative uses: processing, biofuels, animal feeds Less crop reach food market Prices increase Poor populations become more food insecure Developed country Large food secure population – smaller food insecure population
- 19. What is done with mouldy food? • Feed to chicken • Feed to other animals • Discard in pit, manure • Mix with good crop and mill • Wash, dry, re-cook T. Kiama, unpublished
- 20. Objectives of feed standards 1. Protect humans from harmful aflatoxins in animal source foods • Milk is the most high risk animal source food because relatively large amounts of aflatoxins are carried over, and milk is consumed especially by infants 2. Safeguard the benefits people derive from livestock and fish by protecting valuable assets that provide multiple benefits • These include income, food and nutrition security, draft power, manure and social/cultural benefits 3. Protect value chain actors from fraudulent or defective products 4. Encourage fair trade, competition and economic growth through promoting standards and credibility 5. Safeguard the welfare of animals
- 21. National regulation on aflatoxins in livestock and fish feeds • Very wide range in standards (suggests lack of coherence) • Standards stricter for sensitive species and ages • Standards stricter for low risk foods (suggests pragmatism > food safety) • Standards stricter for non- tropical countries (suggests protectionism?)
- 22. Highly susceptible: oral LD50 (<1 mg per kg body weight) Rabbits, ducks, cats, swine, rainbow trout Moderately susceptible: oral LD50 (1-2 mg per kg body weight) Dogs, horses, calves, turkeys, guinea pigs, sheep, baboon Relatively resistant: oral LD50 (5-10 mg kg body weight) Chickens, rats, macaque monkeys, mouse, hamsters One teaspoon of aflatoxin is enough to kill 2,500 rabbits
- 23. Standards and policies Ref: Wu. VOL. 38, NO. 15, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY FDA limits Aflatoxin standards for feeds and feed materials should be based on tolerable ranges plus a margin of safety. Generally tolerable ranges are: ≤50 ppb in young poultry, ≤100 in adult poultry, ≤50 in weaner pigs, ≤200 in finishing pigs, <100 in calves, <300 in cattle and <100 in Nile tilapia.
- 24. Feeding livestock contaminated feed Livestock produce less because of toxic effects Animals metabolize toxins Aflatoxin contaminated feed given to livestock instead of humans Less aflatoxin contaminated crops reach humans- less crops reach food market A reduced amount of aflatoxins may reach humans through animal-source food Less animal-source food produced, reduced livelihoods of farmers
- 25. Standards for Anti-Mycotoxin Additives (AMAs) in Feeds Clays (aluminosilicates) • Most effective binder but different clays vary in effectiveness Yeast/bacterial cell wall extracts • Provide other useful nutrients, but evidence on effectiveness is mixed Other binders • Some are promising but less evidence of effectiveness • Over 100 companies offering AMAs • In the Brazilian market, where approximately 100 AMAs for poultry and swine were evaluated, only about 30% were effective
- 26. Need of revising feed standards? High levels of aflatoxins, need of alternative use for contaminated foods, and implications for food security and livelihoods would support feed standards that are less rather than more strict. Need for approving safe and suitable AMAs for livestock and fish feeds. Livestock revolution with rapidly growing pig, poultry and aquaculture sectors plus the availability of effective mycotoxin binders offers a pathway to take contaminated grains away from human consumption and safely use to produce much needed, highly nutritious animal source foods
- 27. How can it be financed? 1. Farmers pay: if crops of other desirable characteristics (drought resistance) or premium market. Afla-safe example of premium market with contracted buyers. 2. Buyers pay: Importers, large programs (World Food) require aflatoxin safe. Scope for processors, manufacturers to also demand (and pay for) safer foods 3. Consumers pay: Premium markets. Aflatoxin-free certified dog food on the market in Kenya. Experiments indicate consumers WTP for safe maize and milk 4. Projects support: much of the GAP and bio-control is supported by development actors
- 28. Who are the stakeholders? Multi-stakeholder approaches PACA (Partnership for aflatoxin control in Africa) – success in bringing stakeholders together (public health under-represented)
- 29. Take home message • Effective ways to reduce aflatoxin exist, but incentives are lacking in poor countries for widespread adoption • Research on full health impacts and ways to finance aflatoxin mitigating practices a priority • Livestock feed sector + binders an attractive mechanism to suck contaminated grain out of human food chain • Potential for aflatoxin regulation to cause harm (burden on agricultural sector, concentrating contaminated among poorest)
- 30. Conclusions There is no silver bullet to eradicate aflatoxins -A battery of interventions to provide safer food in a world full of food safety hazards!
- 31. The ILRI work is financed by the Ministry of Foreign Affairs, Finland It is implemented in a partnership with the International Food Policy Research Institute (IFPRI), MTT Finland, Biosciences in eastern and central Africa (BecA) It contributes to the CGIAR Research Program on Agriculture for Nutrition and Health, led by IFPRI Acknowledgements
- 32. The presentation has a Creative Commons licence. You are free to re-use or distribute this work, provided credit is given to ILRI. better lives through livestock ilri.org