Impact of Aflatoxin on Health and Trade in Africair4.rutgers.edu/GMUS/Nairobi Bio Evalworkshop/healthandtrade... · Impact of Aflatoxin on Health and Trade in Africa Ranajit Bandyopadhyay

International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org

Impact of Aflatoxin on Health and

Trade in Africa

Ranajit BandyopadhyayIITA-Ibadan, Nigeria


Outline

• Food systems

• Prevalence of aflatoxins

• Exposure to aflatoxins

• Impact on health and its cost

• Impact on trade and its cost

• Mycotoxin regulations and challenges in Africa


Food Systems

Large Scale and Regulated – Developed countries– Trade based– Advanced infrastructure– Capital intensive

Tim Williams, Peanut CRSP

Small Scale and Unregulated – Developing countries– Informal markets– Subsistence– High food insecurity



Prevalence of Aflatoxins in Food• Aflatoxins are toxic substances produced by highly prevalent and

ubiquitous Aspergillus fungi• High levels from Kenya, Benin, Burkina Faso, Cameroon, Gambia,

Ghana, Guinea, Mozambique, Nigeria, Senegal, South Africa, Zambia…….

• Frequency of occurrence high– >30% maize in stores with >20 ppb aflatoxin– ~90% stores are contaminated with Afla fungi– Up to 50% grain in households with aflatoxin

• Several African staple commodities affected – maize, groundnut, cassava, sorghum, yam, rice, cashews

• Food basket surveys limited

• Environmental conditions, traditional farming methods and improper grain drying and storage practices


Aflatoxin Contamination in W. Africa

Maize: 4000 – BeninPeanut: 216 – GhanaSorghum: 80 – GhanaMillet: 200 – NigeriaTiger nuts: 120 – Nigeria

Primary products• Peanut paste: 3278 – 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: 7600 – Nigeria• Local beer: 135 - Nigeria

Food products MTL = 20 ng/g


Aflatoxin-albumin adducts (pg AFB1-lysine eq./mg albumin)

<5 5-25 26-100 >100

Num

ber o

f ind

ivid

uals

(%)

0

20

40

60

80

100 Gambia (n = 950)Benin (n = 479)USA (n = 48)Europe (n = 74)

Aflatoxin Exposure in Africa, Europe & USA


Synergistic interaction with Hepatitis-B & C

Malnutrition

Liver cancer

Trade Restrictions

Quality reductionAflatoxin

contamination in food and feed

Reduced ability to cope with diseases, especially HIV/AIDS

Liver cirrhosis, immuno-suppression, blocks nutrient absorption, growth

abnormalities, etc.

Aflatoxins


Aflatoxin and Human Health

Death Contributes to 40% of DALYsImpairs growth and development of childrenSuppress immune systemAflatoxin interacts with HBV• 30 times more potent in

HBV+ people• 5-60 times higher cancer

riskMay impede uptake and utilization of micronutrients in human systemsAssociated with Kwashiorkor in children


Aflatoxin poisoning in Kenya

• Eastern and central provinces – Jan to Jul, 2004• True magnitude greater than reported• 317 cases reported with 125 deaths (CFR 39%)

– 22% patients <5 years; 29% 5-15 years; 49% >50 years– 88% in 4 districts: Makueni, Kitui, Machakos & Thika– CFR highest in Makueni district (CFR = 49.3%)

• Nearly 50% samples had >20 ppb aflatoxin B1

• School-feeding program – 26 deaths in 2005• Significant risk factors:

– consumption of homegrown cooked maize kernels – possession of discolored or visibly moldy homegrown maize– storage of damp maize Nyikal et al. 2004

Presenter

Presentation Notes

A case of suspected aflatoxin poisoning was defined as a case of acute jaundice that occurred after January 1, in a resident of Eastern or Central Province or a case diagnosed at Kenyatta National Hospital in a patient who was not known to have chronic liver disease or any other cause of jaundice. CFR means case-fatality rate Ingestion of 2--6 mg/day of aflatoxin for a month can cause acute hepatitis and death (5,6).


Distribution (%) of aflatoxin (ng/g) in maize products in Kenya, 2004

District Products (No.) < 20 21-99 100-1000 >1000

Makueni 91 35 13 40 12

Kitui 73 38 21 32 10

Machakos 102 49 25 23 3

Thika 76 66 17 13 4

TOTAL 342 47 19 27 7

Nyamongo et al

Max 25,000 ppb

Or 1200 times

MTL


Drought, high temperature stress and unseasonal rains increase aflatoxin in maize and groundnuts

Increase of duration and area under drought would further accentuate the aflatoxin

problem

Climate Change and Aflatoxin in Kenya

The 2004 Aflatoxin outbreak. Increasing aflatoxin in market maize in brown.

Blue circles –aflatoxin deaths

INCREASING RISK OF AFLATOXIN OUTBREAKS IN MAKUENI AND MACHAKOS


Medical epidemiology – Aflatoxin

• Focused on children

• Transversal (across zones): Survey 16 villages, 4 zones; 497 children; 9 months to 5 years

• Longitudinal (across time): 2 zones; 4 villages; 200 children; 3 times (Feb/Mar, May/Jun, Oct/Nov); 16-37 month

• Ethical approval from Governments

• IITA-NARS-University of Leeds collaboration in Togo and Benin

Presenter

Presentation Notes

497 children, 99% aflatoxin positive, 33% stunted growth, 29% underweight Aflatoxin contamination averaged >100 ppb (safe limit: 20 ppb) in up to 30% grain stores.


Blood aflatoxin-alb in 6–48 month old infants in AEZ

SS NGS SGS CSZones

pg a

flato

xin μl

-1bl

ood

0.0

250.0

Benin and Togon = 480

16 villages30 per village

Presenter

Presentation Notes

Variation in AF-alb level by eco-zone was marked and statistically significant. In the SGS average adduct levels were 5 times higher than in the SS. Children in the NGS and CS had AF-adduct levels that were in between those of children from the SGS and SS (resp. 54.86, 42.20, 128.47 and 25.28 pg/mg, see Graph 2). Presumably aflatoxin exposure within each zone should be similar. After statistical analysis, this presumption proved valid for the SS and NGS only. Within the SGS and CS, villages differed significantly from one another.


Afla-alb adduct level and weaning status

Weaned

Unadjusted Adjusted

1.8X

Gong et al., 2003

Presenter

Presentation Notes

Figure 1 Aflatoxin-albumin (AF-alb) adduct level and weaning status in children. Aflatoxin-albumin adducts levels in: breastfed (n = 158; white) and weaned (n = 144; shaded) children aged 3 years. Unadjusted geometric means were 45.6 (95% CI: 38.8–53.7) and 18.0 (95% CI: 15.2–21.3) for weaned and breastfed group respectively. After adjusting for age, socioeconomic status, and agro-ecological zone in a multivariable model there was a highly significant difference between adduct levels in weaned and breastfed children (P = 0.0001). The adjusted geometric means were 37.7 (95% CI: 30.8–46.1) and 21.1 (95% CI: 17.5–25.5) for the weaned and breastfed groups respectively. **P 0.0001.


Effect of aflatoxin exposure in children

• Stunting - 40% more frequent in the high exposure zone

• Underweight - 45%; no differences between zones

• Sex– No difference

Aflatoxin exposure group

AF-alb adduct(pg mg-1)

Ht. increase*(cm)

Lower quartile <23.3 5.88

Upper quartile >101.5 4.21


Factors related to aflatoxin exposure

• Aflatoxin content of maize

• Maternal education and socio-economic status – no effect

• Maize-based weaning food

• No. of A.flavus colonies of more toxigenic strain in stored maize


Confounding Toxicological Effects

• Poisoning modes– Acute poisoning

• Clear symptoms– Chronic exposure

• Indirect symptoms usually attributed to other agents– Immune suppression -> infectious diseases– Nutritional interference -> vitamin deficiencies– Developmental interference

– Cumulative exposure• Genetic and carcinogenic

• Medical professionals need better information


Wrong Emphasis on Aflatoxin and Human Disease (Gong et al)

Health effectPossible

deaths (No.)Relative public

attention

Biological weapon 0 (?) Very high

Acute aflatoxicosis 100’s High

Hepatocellularcarcinoma

10,000’s Medium

Growth impairment/ immunosuppression

100,000’s (?) Low/None


Animal Health Impact of Aflatoxin

Livestock and poultry lossesliver damage including cancerrecurrent infection due to immune system suppressionreduced growth ratelosses in feed efficiencydecreased milk and egg yieldembryo toxicity (reduced reproductivity)death (cattle, turkey, poultry, swine..)


Social cost (A$) – Spoilage and Human*

Sector Maize G-nut Total

Spoilage 70.9 36.8 107.7

Human – premature death

112.7 73.2 185.9

Human –disability/morbidity

63.8 41.5 105.3

*Human life difficult to cost. But, partial costing of economic surplus forgone:√Cost of productive capacity lost due to mortality; Cost of productive capacity due to morbidity/hospitalization×Cost incurred by Govt. hospitals; intangibles: pain, suffering, anxiety, quality of life….

Presenter

Presentation Notes

4.2 Evaluating the costs of the human health effects of aflatoxins There are two main approaches to the study of disease in a community. One approach estimates disability-adjusted life years lost due to premature death and increased morbidity. Examples of this approach include World Bank (1993). The aim in computing life years lost is to give some impression of the nature and degree of ill health in a community. This approach does not generally produce a monetary cost of disease. A second approach estimates the monetary cost of disease. Examples of this approach include Crowley et al. (1992). This paper uses the second approach because it generates a meaningful, though partial, monetary measure of the cost of disease. It is partial because it does not cover all impacts of disease. For example, it does not incorporate the effects of disease on quality of life or human suffering, for which satisfactory measures are still being developed (Crowley et al. (1992)). Disease leads to the following categories of cost (see Crowley et al. (1992)): · the cost of mortality which relates to the cost of productive capacity lost when people die prior to reaching the end of their productive life; · the cost of morbidity which relates to value of production loss resulting from hospitalisation and the cost of health care services consumed when an individual is sick; · the costs incurred by governments and hospitals in the provision of medical services for individuals suffering from primary liver cancer; and the cost of intangibles - pain, suffering, anxiety and reduction in quality of life. In this paper, the cost of the human health effects of fungi and aflatoxins include only the first two categories of the cost of primary liver cancer. The estimation of the costs in the third category requires data on the number and lengths of visits made by primary liver cancer patients to hospitals, medical centres and medical facilities, the type of medical personnel that attended them, the drugs and other pharmaceutical products prescribed and whether they were hospitalised or not. This category was excluded mainly because the data needed to enable their estimation is not available. The last category was excluded because at this time, there are no satisfactory monetary measures of the intangible cost of disease. Determining the value of life can be controversial. On one extreme is the assumption that the value of an individual life is infinite. This assumption, however, is not helpful (BTCE (1993)). This paper assumes that human life has a finite value. There are two main methods for determining the finite value of life (Crowley et al. (1992)): · the human capital approach; and · the willingness to pay. The human capital method equates the value of life with the present value of expected future earnings. The willingness to pay method uses contingency valuation surveys to ask people how much they would be willing to pay to avoid different levels and types of risks. The willingness to pay approach is inappropriate when people surveyed cannot perceive the risk whose cost they are asked to assess. In the case of aflatoxin-related primary liver cancer deaths in the Southeast Asian region it is not clear that people consuming aflatoxin-contaminated maize and peanuts realise the risk they face from aflatoxin-related primary liver cancer. This paper uses the human capital approach to estimate the cost of life.


Social cost (A$) – Animals and Total

Sector Maize G-nut Total

Poultry meat* 28.9 2.5 31.4

Poultry egg* 6.6 0.6 7.2

Pig meat* 36.2 3.1 39.3

TOTAL 319.1 157.7 476.9

*Increased mortality and reduced feed efficiency


Wine

Coffee

Cocoa

Maize

HazelnutsGroundnuts

ExportCrops


Trade Losses due to Aflatoxins

• Export compliance with food safety and quality standards.

• CODEX standard: 20 ppb; EU: 2 ppb• African exports: EU (51%) & US (22%)• World Bank estimate of lost trade

– 2005 study: ~ Tens of millions of $

• Some countries active to meet standards by putting in place relevant institutions

• Best quality exported; poorer quality consumed domestically.

Peanut

Maize

Coffee

Cocoa

Presenter

Presentation Notes

EXPAND Groundnut kernel and maize earhead infected with Aspergillus flavus. Milk (contaminated with Aflatoxin M1) poured into drain. The reduction in aflatoxin standard in EU will result in one less death in EU in two years. But cost to African nations is huge. This is a non-tariff trade barrier. This is based on a World Bank study by Otsuki et al (2001). The Asian study is from Lubulwa (1996)


EU Rejections of Imports According to Risks

SOURCE: EU Rapid Alert System For Food and Feed (RASFF, 2005)


Meeting Aflatoxin Standards Benefits Exporting Nations

• Cost of compliance is a source of concern for several developing countries

• These challenges are manageable, and compliance is a worthwhile investment.

• Nigeria and Senegal major groundnut exporters in 1960s, but completely lost the export market since 1980s.

• Senegal: US$ 4.1 million added capital investment cost 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.• Fair Trade groundnut export from Malawi.


Factors influencing mycotoxin regulations

• Availability of toxicological data• Availability of food consumption &

exposure data• Availability of survey analytical data• Availability of methods of sampling

and analysis• Trade contacts with other countries• Sufficiency of food supply


Food intake determines exposure

Fumonisin B (mg/kg)

Probable Daily FB Intake (μg/kg body weight/day)

Europe (10)* Nigeria (150) Kenya (400)

0.2 0 0.5 1.4

1.0 0.2 2.5 6.6

2.0 (ML) 0.3 5.0 13.0

4.0 0.7 10.0 27.0

SafeNephrotoxicity (0.8 – 2.0)> PMTDI

(After Marasas et al., 2008)

*Maize intake (g/60 kg person/day)


Mycotoxin regulation in Europe & Africa

• All EU member states have regulations for 12 mycotoxins

• 15 African countries have regulations (59% pop).

• Most countries not regulated, but say that regulations needed

• Does not mean problem does not exist

• For small-scale & subsistence systems regulation has failed

Source: FAO, 2004

Presenter

Presentation Notes

Nigeria has regulations for 20 ppb in food; Ivory Coast’s regulations vary from 10-100 ppb depending on use of commodity


Standard setting institutions

JECFA

National governmentsRegional Commissions

Members debate on JECFA recommendations, sets maximum tolerable limits (MTLs), codes of practices

CODEX

Expert panel evaluates data, seeks more data if necessary, makes recommendation on PTDI

Evaluate CODEX recommendations,propose, legislate and enforce MTLs

WTO and SPS regulations


Mycotoxin standards……..

• National governments decide based on JECFA & CODEX recommendations

• Important for trade• Harmonization critical, such

as in MERCUSOR countries

• ALARA (As Low As Reasonably Achievable) principle

• Leaves room for dispute

0

5

10

15

20

25

30

0 1 3 4 5 10 15 20 30 35Total aflatoxin (ng/g)

Countries (No.)


Loss disputes – World Bank vs. EU

• Aflatoxin limit: 4 ppb in EU vs. 20 ppb

• Otsuki et al. (WB) modelled (econometric) loss for 7 African nations as US$670 million


• Following request from the EU, the WB revisited the study

• Losses for Africa, recalculated as several hundred thousand US$

• Countries most affected are Argentina, Brazil and USA


Kenkey – Ghana’s national food

• Corn based• Meal wrapped

in leaves and boiled

• Common food• Street vendors


Aflatoxin as sensational

news

Victim: Aflatoxin awareness campaign



Need for mycotoxin testing and monitoring

• Protect consumers from undue exposure

• Promote regional and international trade• Stringent regulatory standards in

importing countries (e.g., EU)• Rapid Alert Reporting System globally

reports food safety issues (on internet) – poor country image

• To promote regional and international trade

• To encourage national development of agro-based economies

• To protect consumers from economic exploitation


Sampling protocol for aflatoxin

Weight of the lot (t)Number of incremental samples/Weight of the aggregate sample (kg)

≤ 1 10 (1)> 1 to ≤ 3 20 (2)

> 3 to ≤ 10 40 (4)

> 10 to ≤ 20 60 (6)> 20 to ≤ 50 100 (10)

For poor farmers grains, the sampling and analytical cost would be higher than potential net profit achievable from such sale


Challenges of Regulations in Developing Countries

• Poor regulatory and control systems• Lack or inadequate national standards and

regulations• Informal and dispersed markets, low volume• ~90% producers consume production at

home• Inadequate inspection and enforcement

capabilities


Challenges of regulatory labs in developing countries

• Inadequate infrastructure – building, electricity, water, telecommunication, computerization

• Lack of trained personnel• Sustainability of laboratory supplies

– Mostly imported– High costs for good quality– High cost per test (HPLC: ~ $150, ELISA: ~ $80)– Reference standards – issue of biohazards and terrorism

• Instrument maintenance and repairs– Lack of technical expertise, reliance on overseas engineers – Long downtimes, low output

• QA/QC and laboratory accreditation for international acceptability

• Political will – convincing policy makers; competing needs

Presenter

Presentation Notes

Convincing policy makers on the need to meet regulatory requirements of importing countries in order to participate international trade in food Committing meager resources to mycotoxin monitoring in the face of competing needs QA/QC and laboratory accreditation – For international acceptability of analytical results ISO 17025 specifies quality criteria for operations in a laboratory prior to accreditation Cumbersome and often underestimated Sustainability of the quality system


Summary

• Aflatoxins in food and feed pervasive in Africa.

• Negative impact overlooked – chronic, unseen.

• Serious effect on children’s growth & development.

• Export potential of primary raw material unrealized.

• Institutions related to food safety very weak.

• New approaches, tools and coalition to manage aflatoxin.


IITA Campus, Ibadan

Documents

Impact of Aflatoxin on Health and Trade in Africair4.rutgers.edu/GMUS/Nairobi Bio Evalworkshop/healthandtrade... · Impact of Aflatoxin on Health and Trade in Africa Ranajit Bandyopadhyay