Improving Food Safety for Human
and Animal Health
Lessons from Infectious Disease Control

Felicia Wu, PhD
John A. Hannah ...
Relevance to One Health
 Food safety is key to human, animal & environmental health.
 Mycotoxins – fungal toxins in food...
Motivating question
“I told a man on the plane that I’ve been working for the last
30 years on how to get rid of aflatoxin...
How can we control foodborne
mycotoxins, to protect human
& animal health?
Insights from other attempts to control microor...
Top 10 causes of death, low- vs. highincome nations (WHO 2011)
Lower resp. infections
Diarrheal diseases
HIV/AIDS
Heart di...
Top 10 causes of death in US in 1900 look
similar to those of low-income nations today

CDC (2010). National Vital Statist...
In US, infectious disease death rates have
dropped dramatically since 1900

Aiello AE, Larson EL (2002). Lancet Infectious...
Mycotoxins: What are they?
 Toxic & carcinogenic chemicals
produced by fungi
 Long history of mycotoxins affecting
socie...
Common mycotoxins in our
food supply
MYCOTOXIN

Produced by fungi…

In crops…

Human health effects

Aflatoxin

Aspergillu...
ONE HEALTH: We can apply lessons from
controlling infectious diseases to
controlling food safety

 Prenatal care
 Sanita...
Prenatal care
 Prenatal care: health services
pregnant women receive to
optimize maternal & child health

Problems endang...
Plant breeding to reduce
fungal infection / toxins
As with prenatal care: optimize chances, before food crops
are planted,...
Sanitation
Clean
water

Improved sanitation could reduce
global disease burden by 10% (WHO 2009)

Toilet
construction

Eff...
Good agricultural practices (GAP)
As with sanitation: GAP provides
environment that allows food crops
to grow healthily

P...
Vaccines
 Vacca: Latin for “cow”








Named by Dr. Edward Jenner
1796: 1st smallpox vaccine from
cowpox pustule
18...
Biocontrol

Photos: R Bandyopadhyay

 As with vaccines: apply
 Biocontrol: use of organisms to
“harmless” version of mic...
Quarantines
 Compulsory isolation to prevent spread of disease
 Venetian quarantena (quaranta giorni)




1377: Venice...
Sorting
As with quarantines:
Isolate infected individuals
(kernels) and remove, to
reduce mycotoxin load
 Hand sorting

...
Antibiotics
Compounds that kill bacteria or
slow their growth


1928: Alexander Fleming’s
staphylococcus cultures in lab
...
Fungicides
 As with antibiotics: kill
pathogen outright

 Effectiveness depends on:



Local weather conditions
Timing...
What has worked in public health, but has
no analogy (yet) in mycotoxin control
 Case study: Smallpox eradication
 Small...
Discovery & use of
smallpox vaccine
Cowpox on human arm

 Observation: dairymaids had no smallpox





Mild cowpox ins...
How did the world become smallpoxfree by 1980?
1. Government support

2. Cost-effective solutions

 $2.4 million/yr from ...
But molds, mycotoxins, & other food
contaminants differ from smallpox…
Smallpox
 Only reservoir: humans
 Easily identifi...
What lessons can we take from smallpox
eradication for food safety efforts?
 Government support critical


Convince poli...
Public health mistakes in infectious
disease control, & lessons learned
 Hepatitis C virus from antischistosomal syringes...
Hepatitis C virus (HCV) from
antischistosomal syringes (Egypt)
 Schistosomiasis endemic in Egypt: 1960s-70s treatment
cam...
Arsenic (As) in well water
(Bangladesh)
 1970s, Bangladesh: polluted surface waters  high
infant mortality





UNICE...
Summary
 Public health & food safety control follow similar principles.
 “How could I have worked on this problem for th...
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Climate Change and Food Security: Insights from Infectious Disease Control

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GRF 2nd One Health Summit 2013: Presentation by Felicia Wu, Michigan State University

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Climate Change and Food Security: Insights from Infectious Disease Control

  1. 1. Improving Food Safety for Human and Animal Health Lessons from Infectious Disease Control Felicia Wu, PhD John A. Hannah Distinguished Professor Department of Food Science & Human Nutrition Department of Agricultural, Food, & Resource Economics Michigan State University, USA GRF One Health Summit, Davos, Switzerland, 17 November 2013
  2. 2. Relevance to One Health  Food safety is key to human, animal & environmental health.  Mycotoxins – fungal toxins in food crops – among most dangerous foodborne toxins   Aflatoxin causes >100,000 cancer deaths/year worldwide Mycotoxins impair child growth & immunity  5 billion people worldwide exposed to uncontrolled aflatoxin in food (mostly through maize, peanuts) 2
  3. 3. Motivating question “I told a man on the plane that I’ve been working for the last 30 years on how to get rid of aflatoxin in food. He probably thought I was stupid. How could I have worked on this problem for 30 years and still not have figured out how to get rid of aflatoxin?” – Dr. Gary Payne, Purdue University meeting Short answer: Because it is difficult to control microorganisms. Long answer… 3
  4. 4. How can we control foodborne mycotoxins, to protect human & animal health? Insights from other attempts to control microorganisms… Infectious disease control    What has worked  Similar in mycotoxin control in our food What has worked  No analogy in mycotoxin control yet  Success story: Smallpox eradication What hasn’t worked: Lessons for food safety 4
  5. 5. Top 10 causes of death, low- vs. highincome nations (WHO 2011) Lower resp. infections Diarrheal diseases HIV/AIDS Heart disease Malaria Stroke Tuberculosis Low birth weight Birth traumas Neonatal infections Heart disease Stroke Respiratory cancers Alzheimer/dementias Lower resp. infections COPD Colorectal cancers Diabetes mellitus Hypertension Breast cancer 0 2 4 6 8 10 12 0 2 4 6 8 10 12 14 Low-income nations: High-income nations: Infections contribute highly to deaths Infections contribute little to deaths 5 16
  6. 6. Top 10 causes of death in US in 1900 look similar to those of low-income nations today CDC (2010). National Vital Statistics Report 58:19 6
  7. 7. In US, infectious disease death rates have dropped dramatically since 1900 Aiello AE, Larson EL (2002). Lancet Infectious Dis. 2:103-110. 7
  8. 8. Mycotoxins: What are they?  Toxic & carcinogenic chemicals produced by fungi  Long history of mycotoxins affecting society      Leviticus 14:37 11th c.: Claviceps purpurea produces ergot in rye  St. Anthony’s Fire Mysterious human & animal deaths in 1930s (Great Depression horses) 1960 aflatoxin discovery: UK turkey deaths Today: several dozen mycotoxins identified ↓ 8
  9. 9. Common mycotoxins in our food supply MYCOTOXIN Produced by fungi… In crops… Human health effects Aflatoxin Aspergillus flavus, A. parasiticus Maize, peanuts, tree nuts, dried coconut, spices Liver cancer, acute liver failure, immune toxicity, child stunting Fumonisin Fusarium verticillioides, Maize F. proliferatum Possibly esophageal cancer and neural tube defects Deoxynivalenol F. graminearum, F. (DON, vomitoxin) culmorum Maize, wheat, barley, oats, beer GI disorders, immune toxicity Zearalenone See above See above Estrogenic effects Ochratoxin A Penicillium verrucosum, A. ochraceus Maize, dried fruits, Nephritic syndrome, possibly other kidney conditions wine, wheat, chocolate, cereals, dried meats, coffee
  10. 10. ONE HEALTH: We can apply lessons from controlling infectious diseases to controlling food safety  Prenatal care  Sanitation  Vaccines  Quarantines  Antibiotics Plant breeding (conventional, GM) Good agricultural practices (GAP) Biocontrol Sorting Fungicides 10
  11. 11. Prenatal care  Prenatal care: health services pregnant women receive to optimize maternal & child health Problems endangering mother or baby detected and treated prior to birth:  Neonatal infections, birth trauma, low birth weight: 3 top killers in low-income nations (WHO 2011) Weight & blood pressure measurement  US: Babies with no prenatal care 5 times more likely to die in 1st 27 days (U.S. DHHS 2006) Fetal heart rate measurement Urine & blood tests Nutritional & behavioral counseling 11
  12. 12. Plant breeding to reduce fungal infection / toxins As with prenatal care: optimize chances, before food crops are planted, that they will resist disease Conventional breeding Transgenic breeding (GMOs) Select for crop genotypes with lower disease / mycotoxin levels Bt maize: reduce mycotoxins indirectly through reduced insect pest damage RNA interference (RNAi)-based host induced gene silencing to “turn off” fungi’s toxin production 12
  13. 13. Sanitation Clean water Improved sanitation could reduce global disease burden by 10% (WHO 2009) Toilet construction Effective sewer systems Clean food Handwashing with soap 2005: 1st time in 40 years that # children <5 dying annually fell below 10M worldwide  Top reason: improved access to clean water & sanitation (WHO 2009) 13
  14. 14. Good agricultural practices (GAP) As with sanitation: GAP provides environment that allows food crops to grow healthily Postharvest interventions reduced aflatoxin by 69% in Guinea peanuts, West Africa GAP: principles applied to on-farm production processes  safer food, agricultural sustainability   Crop rotation, tillage, planting date, irrigation, fertilization, pest control Harvesting date, sorting, proper drying & storage, pest control (Khlangwiset & Wu 2010)     Education on hand-sorting nuts, drying Natural-fiber drying mats, storage bags Wooden pallets for storage bags Insecticides for storage room floor (Turner et al. Lancet 2005) 14
  15. 15. Vaccines  Vacca: Latin for “cow”     Named by Dr. Edward Jenner 1796: 1st smallpox vaccine from cowpox pustule 1881 Pasteur “vaccine”: any inoculated material that produces immunity Weakened or killed form of microbe applied Today: Vaccines for 14 viruses & 11 bacteria in humans  UN Millennium Development Goal:   If 90% children worldwide given routine vaccines, prevent 2 million deaths/yr by 2015 (WHO 2011) GAVI (WHO & Gates Foundation)   In 10 yrs: 288M children vaccinated against diphtheria, tetanus, pertussis, hepatitis B, Hib 5M deaths prevented 15
  16. 16. Biocontrol Photos: R Bandyopadhyay  As with vaccines: apply  Biocontrol: use of organisms to “harmless” version of microbe, to reduce incidence of pests or toxins prevent damage from more  Not all Aspergillus flavus strains harmful type produce aflatoxin   Competitively exclude toxigenic strains with non-toxigenic strains Can reduce aflatoxin  80% 16
  17. 17. Quarantines  Compulsory isolation to prevent spread of disease  Venetian quarantena (quaranta giorni)   1377: Venice helped curb bubonic plague by quarantining ships in Ragusa (Dubrovnik) 40 days 1665: Villagers of Eyam, England, stopped plague spread by selfquarantine  Today: many nations have quarantine laws  Protect human health (travelers with infectious diseases may face isolation), animal health, plant health 17
  18. 18. Sorting As with quarantines: Isolate infected individuals (kernels) and remove, to reduce mycotoxin load  Hand sorting  Removing obviously moldy kernels can significantly reduce aflatoxin & fumonisin contamination in food (Afolabi et al. 2006, van der Westhuizen et al. 2011)  Industrial sorting   UV light to detect aflatoxincontaminated kernels Changing combine harvester configurations to sort out Fusarium-damaged grains 18
  19. 19. Antibiotics Compounds that kill bacteria or slow their growth  1928: Alexander Fleming’s staphylococcus cultures in lab   Penicillium in one dish destroyed bacteria “Mould juice” (penicillin) found to be effective against scarlet fever, pneumonia, meningitis, diphtheria, gonorrhea, syphilis, etc. Today: >150 antibiotics developed   Before antibiotics, infections caused >33% all deaths in US >200M lives saved by penicillin (Roberts & Ingram 2001) Dangers of overuse   Adverse gastrointestinal effects Antibiotic-resistant bacteria 19
  20. 20. Fungicides  As with antibiotics: kill pathogen outright  Effectiveness depends on:   Local weather conditions Timing  Azole fungicides (e.g., Prosaro®) inhibit sterol  Fungal prediction models help biosynthesis in Fusarium; growers assess when to apply control scab & toxins in oats, fungicides barley, wheat (Paul et al. 2011) (De Wolf et al. 2003, Schaafsma & Hooker 2007, Schmidt-Heydt et al. 2011) 20
  21. 21. What has worked in public health, but has no analogy (yet) in mycotoxin control  Case study: Smallpox eradication  Smallpox caused by viruses Variola major, minor    High fever, extensive rash: 30% mortality Blindness, permanent disfiguration in survivors Sanskrit medical texts: 1500 BCE  1700s: killed ~400,000 Europeans/yr  Devastated previously unexposed populations (50-80% mortality)    1241: Iceland 1500s: Aztecs, Mayans, Incans 1700s: North American natives 21
  22. 22. Discovery & use of smallpox vaccine Cowpox on human arm  Observation: dairymaids had no smallpox    Mild cowpox instead (caused by related Vaccinia virus) 1796: Dr. Jenner scratched cowpox pus from dairymaid into arm of 8-year-old boy 6 weeks later, scratched his arm with smallpox pus: boy immune!  Vaccinia-based smallpox vaccine spread globally  1967: WHO began effort to eradicate global smallpox, led by DA Henderson 22
  23. 23. How did the world become smallpoxfree by 1980? 1. Government support 2. Cost-effective solutions  $2.4 million/yr from WHO  Cooperation from nations  “Ring vaccination”  Public engagement in finding cases  Bifurcated needle Source: DA Henderson, Smallpox: The Death of a Disease, 2009 23
  24. 24. But molds, mycotoxins, & other food contaminants differ from smallpox… Smallpox  Only reservoir: humans  Easily identifiable disease  Solution cheap, globally effective, globally feasible  Lifetime immunity if vaccinated once Fungi/food contaminants  Multiple natural reservoirs  Disease not always visible  Multiple partial solutions, with limited applicability  “Lifetime” different for crops & animals vs. humans 24
  25. 25. What lessons can we take from smallpox eradication for food safety efforts?  Government support critical  Convince policymakers that mycotoxins are important  Public involvement critical  Engage public in surveillance & adoption efforts  Not enough for interventions to be cheap: they should also be applied cost-effectively  What’s minimum amount needed to achieve desired food safety in low-income regions? 25
  26. 26. Public health mistakes in infectious disease control, & lessons learned  Hepatitis C virus from antischistosomal syringes (Egypt)  Arsenic in well water (Bangladesh)    Scenario Mistakes made Lessons for food safety control 26
  27. 27. Hepatitis C virus (HCV) from antischistosomal syringes (Egypt)  Schistosomiasis endemic in Egypt: 1960s-70s treatment campaign using repeated emetic tartar injections  Mistakes made: Hepatitis C spread by unsterilized needles: Egypt has highest HCV rate in world (14-20%)  Lessons for food safety control: Ensure delivery method of intervention is safe 27
  28. 28. Arsenic (As) in well water (Bangladesh)  1970s, Bangladesh: polluted surface waters  high infant mortality    UNICEF: >8M wells Infant mortality halved, but ~50% population exposed to As >> 50 µg/L (Smith et al. 2000) Blackfoot disease; skin, lung, bladder cancers  Mistakes made: lack of learning from past mistakes Photos: Smith et al. (2000). (Taiwan) WHO Bull 78(9)1093.  Lessons for food safety: Consider risks of interventions; be well-informed of past mistakes 28
  29. 29. Summary  Public health & food safety control follow similar principles.  “How could I have worked on this problem for thirty years and still not have figured out how to get rid of aflatoxin?”   Eradicating smallpox took ~200 years since 1st vaccine; >3500 years since first documented Eradication of mycotoxins and food contaminants unlikely, but thoughtful prevention & control are crucial  One Health: Not only are health & agriculture/food safety linked, but we can learn lessons from each other’s fields. 29

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