Postharvest and Food Safety Management for Improved Health and Income

Postharvest and
Food Safety
Management for
Improved Health
and Income

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

Outline

 Introduction
 Factors that influence post harvest quality
 Research to address post harvest
constraints
- post harvest systems analysis
- control of pests
- diffusion and adoption of new
technologies
 Mycotoxin research
 Future needs


Food Systems

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

 Small Scale and Unregulated
– Developing countries
– Informal markets
– Subsistence
– High food insecurity Tim Williams, Peanut CRSP

Post harvest systems in Africa - constraints

• Almost all operations are manual – leading to high
losses and poor quality
• Potential for rapid drying low – high moisture and
increased fungal development
• Storage structures open and often poorly ventilated -
increased losses due to pest and diseases
• Long holding periods in open stores – leading to
theft, infection with pests and diseases
• Poor to no access to storage insecticides
• Poor marketing system - leading to increased losses
and low prices low incentive for increased production


Evaluation of post harvest system

• Development of post harvest insects and fungi in three different
traditional storage structures in Benin
• Vegetable material stores (VMS)
• Mud silo store (MSS)
• Polyethylene bag storage (PBS)
• 4 sites in different agroecological zones, monitored monthly for 7
months
• Serious levels of Sitophilus zeamais (highest in the south and in the
VMS) and Prostephanus truncatus (high levels in the VMS and later
in the season in the PBS)
• Highest moisture content in the coastal zone decreasing towards the
north (16,5% south to 9,9% north)
• Most prevalent fungi were Fusarium spp. highest levels observed in
Aplahoué (south), whereas Penicillium and Aspergillus spp. were
found mostly in Ouessè (middle)

Hell et al. 2008 submitted to Journal of Applied Entomology

Effects of four temperatures (20, 25, 30 and 35 C) and two
relative humidity levels (44 and 80% RH) on development time,
survivorship, age-specific fecundity, sex ratio and intrinsic rate
of natural increase (rm) of S. cerealella
• Minimum development
time occurred close to
32 C and 80% RH for
both males and females. 0,03
High RH
• Development time of
females was significantly 0,02

shorter than that of develop
males. ment 0,01

rate
• Immature survivorship (day-1)
0
was highest between 25- 15 20 25 30 35 40

30 C and 80% RH and
lowest at 35 C. 0,03
females

• The greatest fecundity Low RH
males
(124 eggs per female) 0,02
occurred at 20ºC, 80%
RH. The maximum rm - 0,01
value was 0.086 d-1 at
30 C and 80% RH, but 0
the growth rate declined 15 20 25 30 35 40
ºC
dramatically at 35 C.

L. Stengård Hansen et al. 2004 Journal of Economic Entomology

Prostephanus truncatus
 Prostephanus truncatus serious
pest of stored maize and dried
cassava roots
 Quarantine pest affects
international trade
 Maize losses after 6 months
from 11% before the
introduction of P. truncatus to
more than 35% afterwards
 IITA had projects from 1990 till
2003 (estimated more than 10
mill $ were spent)
 Predator released for the
control
 Impact of this effort was not
evaluated

Teretrius nigrescens G.Goergen

Augmented release
 Cassava chips stored for 5
months in mud silos and 50
adults of T. nigrescens added
 Chip weight and number of NoTn PlusTn

holes on chips differed
between treatments from 2 50
50
months of storage 43 41
45
 After 3 months of storage, 40
losses reached 40 to 50% 35 31
without predator and 30 to

Losses (Kg)
30 25
40% with T. nigrescens. 25
 A farmer can increase his 20 18 18

profit by 1437 fcfa/100kg and 15
12
11
losses are reduced by 11% 10 7

 Twice as many P. truncatus 5 0 0

and holes on chips in stores 0
0 1 2 3 4 5
where T. nigrescens was not
released Month of storage
 Farmers were able to prolong
storage period by 2 months.
Hell et al. 2006 Journal of Stored Products Research


Bruchid control
• Twelve indigenous and exotic isolates of
Beauveria bassiana and Metarhizium anisopliae
were evaluated
• Indigenous isolates from C. maculatus were
more virulent in laboratory bioassays than
exotic isolates from other insects.
• B. bassiana 0362 at both 1x107 and 1x108
conidia g-1 grain led to significant adult mortality
and reduced F1 emergence relative to Most serious pest of cowpea
untreated and beans in Africa
• Effect of the fungus persisted into the F1
generation. The net reproductive rates, R0, The development of a single
measured 26 days after insects were released larva in a kernel can lead to
were 5.16 and 7.32 for the high and low doses weight losses of 8–22%
compared to 9.52 for the untreated control.
• No evidence that cadavers were sporulating in Significant impact on
stored grain need for persistence would depend commercial value – price
on initial inoculum reduced by 40%
Cherry et al. 2005 Journal of Stored Products Research & Cherry et al. 2007 Annals of Applied Biology


Adoption of Improved Mud Silo
 Impact of farmers’ socio- 210 Courbe de diffusion du grenier fermé en terre amélioré
economic factors, 200 Yt=199/(1+ e
-666,99691-0,33281*t
)
technology characteristics 190
180
and farm specific factors, 170
on the adoption of

Nombre de paysans ayant adopté le grenier
160

improved mud silo 150
140
130
120
 Farmers’ socio-economic 110
factors such as the years 100
90
of farming experience, 80
access to extension 70

service, were positively 60
50
correlated with adoption. 40
30
20
 Technology 10

characteristics like cost 1984 1988 1992 1996 2000 2005 2010 2015 2020
0

affected adoption Année d'adoption
negatively and perceived
durability of the store
affected adoption
Hell et al. 2008 Submitted to Int. Journal of Postharvest Technology & Innovation
positively

Adoption of cassava chipping equipment

Variables β Coefficient Standard Error Probability
Gender 0.291 0.769 0.705*
Sale -0.144 0.673 0.831
Education -1.246 0.827 0.132
Processing experience -0.049 0.028 0.079*
Non-tuber incomes -1.945 1.108 0.079*
Contact 1.814 0.748 0.015**
Group Membership 4.274 0.886 0.000***
Agro-Ecological zone -1.355 0.648 0.037**
Average Income -1.221 0.798 0.126
Constant 0.439 1.742 0.801
Pourcentage de prédictions correctes : 89.6 % ; Constante = 0.46217 ; N=212
Ratio de maximum de vraisemblance = 69.218; Chi carré = 72.100***.
(***) : significatif à 1 % ; (**) : significatif à 5 %.

Allogni et al. 2008 Submitted to Bulletin de la Recherche Agronomique.


Mycotoxin R-4-D at IITA
 Aspergillus and Fusarium species diversity and
mycotoxin profile in food baskets (USAID, BMZ, IFAR)
 Breeding for resistance (US-FAS)
 Biocontrol of aflatoxin (BMZ)
 Low-cost detection of mycotoxin
 Development and dissemination of mycotoxin
management strategies (BMZ, ADA)
 Intervention study for the reduction of aflatoxin and
impact on nutritional situation (BMZ)
 Awareness campaign (Rotary International)
 Training & information exchange (USAID, BMZ, EU)


Major classes of mycotoxins

• Aflatoxins: Aspergillus flavus, A. parasiticus
• Trichothecenes: Fusarium spp, Stachybotrys
• Fumonisins: F. verticillioides etc.
• Zearalenone: F. graminearum

• Ochratoxins: Penicillium verrucosum,
A. ochraceous


Prevalence of Aflatoxins in Food
• Aflatoxins are toxic substances produced by highly prevalent
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
• Environmental conditions, traditional farming methods and
improper grain drying and storage practices


Aflatoxin and Fumonisin in W. Africa

Primary products Food products
Maize beverage:
Maize: aflatoxin – 2-560 ppb
• aflatoxin <2ppb
fumonisin – 0-12 ppm
• fumonisin <2ppm
Cassava chips: 0,3-13 ppb Cassava flour: 0,3-4.4ppb
Cowpea: 0.9-18.6ppb
Cashew: 3.0-56 ppb
Egussi: 4.6-32 ppb
Dried vegetables – 3.2-6 ppb


Aspergillus flavus prevalence in
maize in Benin
Aspergillus flavus
prevalence 160000

differs between 140000
120000
zone and season
100000

cfu
80000 AFT
High risk zone
60000
has been 40000
identified 20000
0
SS NGS SGS CS
Ecozones

Tedihoue et al. 2008 Submitted to Plant Disease


Aflatoxin in maize in different
agroecological zones in Benin
High and low risk
1600.0
zones have been
1400.0
identified
1200.0
1000.0
Results vary
ppb 800.0 Aflatoxines
between season 600.0
and years 400.0
200.0
0.0
SS NGS SGS CS
Ecozones

Tedihoue et al. 2008 Submitted to Plant Disease


Mycotoxin risk in different agroecological
zones in Africa

 High aflatoxin risk
zones: moist
savannas (with
bimodal rainfall
patterns) and hot dry
savannas
 Fusarium toxin risk
zones: humid forest
and mid-altitudes
Drier savanna
 Aflatoxin Moist savanna
Humid forest
contamination Moist midaltitude
Drier midaltitude
High altitude
increase with storage
time especially in
drier savanna

Factors that influence mycotoxins

• Climatic (rain, relative humidity, temperature)
• Biotic (insects, damage, incomplete huskcover)
• Abiotic (stress, irrigation, rotation, variety, planting date,
harvest, storage conditions)

Trt Aspergillus spp. Fusarium spp.
Non-protected 3.95 0.82 a 36.05 3.38 a
Protected 2.33 0.62 b 16.62 1.47 b
P 0.0067 <.0001


Climate Change and
Aflatoxin in Kenya

The 2004 Aflatoxin
outbreak.
INCREASING RISK OF Increasing aflatoxin
AFLATOXIN OUTBREAKS IN in market maize in
MAKUENI AND MACHAKOS brown. Blue circles
– aflatoxin deaths

Drought, high temperature stress
and unseasonal rains increase
aflatoxin in maize and groundnuts
>125 people died of aflatoxin
poisoning in 2004, a drought year
Increase in duration and area
under drought would further
accentuate aflatoxin problem

Associated insect species

• Insects play a big role in the
propagation and distribution of Correlation between mean number of insects and toxigenic
fungal species on maize
the fungal spores
• High correlation between certain A. flavus A. parasiticus F.verticillioides

insect species and fungi Prostephanus 0.36* 0.12 0.23
• Pest pressure was low Sitophilus -0.21 0.39* -0.17
Cathartus 0.32* 0.18 -0.31*
• To protect cobs from fungal Carpophilus 0.21 0.13 0.08
infestation a reduction of 40% Tribolium 0.33* 0.48** 0.08
Palorus 0.23 0.42** -0.03
aflatoxin Cryptolestes -0.08 0.40** 0.09
• Cobs with more than 10% of Gnathocerus 0.23 0.24 0.04
damage by insects had aflatoxin * Significant at P = 0.05 and ** P = 0.01
contamination of 388 - 515 ppb
Hell et al. 2000 al., 2004
Hell et African Entomology


Effect of maize variety, and cowpea intercropping
on aflatoxin production during storage

Local variety 1.0E+03

Gbogbe had 8.0E+02
much lower toxin AFB1
Aflatoxin (ppb) 6.0E+02 AFB2
levels than
TZSR-W 4.0E+02

2.0E+02
No effect of
intercropping 0.0E+00
with cowpea

0

1
0

1

P0

P1
P0

P1

LV

LV
IV

IV

C

C
C

C

LV

LV
IV

IV
Tedihoue et al. 2008 Manuscript in preparation


Beninese maize and F. verticilliodes infection

80 80
a a a a a
a A
Stem infection (%)

Inoculation B
60 b 60 Control
b a
a a a a
ab ab ab ab ab ab
40 40 b

* * * * * *
20 * 20
* **
* * * * * * * * * *
0 0
Keb-EMY
DMRY
DMRW

QPM

TZESRW

TZESRW
HPG97
DTSR

TZPB-SR
TZPB-SR
N'gakoutou

DMRW

DMRY
ACR20

ACR94

Keb-EMY

QPM
Gbogboue
Kamboinse

Kamboinse
80
Kernels infection (%)

80
C D
60
60
a
40 * ab
* * * ab ab
40 ab a ab ab ab ab
ab ab bc ab
* * abc abc abc
20 abc c b abc * bc
bc * c * *
20 * *
*
0
TZPB-SR
TZESRW
DMRY

Keb-EMY

QPM
DMRW

Kamboinse

N'gakoutou

0

TZESRW
HPG97
DTSR

TZPB-SR
DMRW

DMRY
ACR20

ACR94

Keb-EMY

QPM
Gbogboue

Kamboinse
A & C 2003 B & D 2004
Dewaminou et al. 2008 submitted to Journal of Phytopathology

Aflatoxin Resistance in Maize Inbreds

1800
Field-03 Field-04 KSA
1600

1400

1200
Aflatoxin (ppb)

1000

800

600

400

200

0
TZMI102

TZMI502
TZM104
1368

1823

Inbred Lines


Mycotoxin Monitoring Tools

• Simple and low-cost diagnostic tool (ELISA)
• Polyclonal antibodies for aflatoxin
– Low-cost (US$ 1-2 per sample analysis)
– Simple procedure, qualitative and
quantitative
– Results comparable to HPLC
– High throughput analysis possible
(100-400 samples/day)
– Less dependency on commercial
equipment
– Ideal test for aflatoxin estimation in
developing countries

Aflatoxin Tested Pet Food
in Nairobi


Mycotoxin Management
Strategies
• Awareness
• Host plant resistance
• Biological control
• Time of harvest
• Grain drying method
• Storage structure
• Storage form
• Sorting and processing
• Insect control


Insect control
• Cobs were protected with mosquito netting, natural or artificial infestation
In protected cobs Pt levels were low rising to means of 1.8 under natural and
14.2 under artificial infestation
Aspergillus and Penicillium incidence was highest on Mussidia nigrivenella,
Carpophilus sp., Prostephanus truncatus and Sitophilus sp. While Fusarium spp.
was mainly associated with the field pests Eldana saccharina and Sesamia
calamistis
Low aflatoxin 0.21 0.16 ppb in T0, whereas insect infestation resulted in 22.74
p 6.99 ppb aflatoxin in T1, and 27.37 7.83 ppb in T2.

Treatment A. flavus A. Insect. Grain Fungal Fungal Total
parasiticus damage losses damage losses aflatoxin
Cobs 8.17±0.86a 0.22±0.14a 10.48±1.4a 4.68±1.03a 6.43±0.44a 0.92±0.24a 0.22±0.16a
protected(T0)
Natural 37.11±1.44b 0.11±0.00a 41.01±2.6b 19.65±1.9b 10.56±0.7a 1.57±0.69a 22.74±6.99b
infestation(T1)
Artificial 47.60±1.50c 0.33±0.14a 50.34±2.9c 27.47±2.4c 9.72±0.67a 1.12±0.49a 27.37±7.83b
infestation(T2)
p 0.0001 0.42 0.0001 0.0001 0.99 0.98 0.002

Mihinto & Hell 2008 Manuscript in preparation

Aflatoxin management

Occurrence (%) of various toxigenic fungal species in maize grains after a 7-day
drying period using different drying methods

Drying method Aspergillus Fusarium Penicillium Others

Cobs on stalk in the field 4.7ab1 98.3a 1.7a 5.3a

Sun drying cobs dried on the ground 21.0a 95.3a 43.7a 10.0a

Sun drying cobs dried on a platform 2.0b 86.3b 4.7b 2.7a

Sun drying cobs dried on a plastic sheets 18.3a 33.3c 9.7b 0.7a

1
Means within a column followed by the same letter do not differ significantly from each other (P < 0.05)

Hell et al. 2008 Mycotoxin Book


Mycotoxin management
• Four storage systems of maize commonly
used by farmers in Benin, West Africa,
were tested to determine their impact on
infection of maize by Fusarium and
fumonisins.
• Fusarium incidence was significantly
higher when maize was stored on a
cemented floor in a house, a non
ventilated facility (40.3 17.4%), than in
the other tested systems (p < 0.05).
• The lowest Fusarium incidence was
recorded when maize was stored in a
bamboo granary (25.5 13.5%) (p <
0.05).
• All maize samples from the tested storage
systems were found to be fumonisin-
positive, with levels ranging from 0.6 to
2.4 mg/kg.

Fandohan et al. 2006 African Journal of Biotechnology


Mycotoxin management

Oils from Cymbopogon citratus,
Ocimum basilicum, and Ocimum
gratissimum were the most 1.6
effective in vitro, completely
inhibiting the growth of F.
Mean total fumonisin level (ug/g)

1.4
verticillioides at lower
concentrations over 21 days of
1.2
incubation
1.0
These oils reduced the incidence
of F. verticillioides in corn and .8
totally inhibited fungal growth at
Storage conditions
concentrations of 8, 6.4, and 4.8
.6
ųL/g, respectively, over 21 days. Clos ed

.4 Open
C. citratus O. gratis simum
Further studies are in progress to
O. bas ilicum Control (no oil)
evaluate the toxicological effects
of these plant substances. Treatments

Fandohan et al. 2004 Journal of Agricultural and Food Chemistry


Simple management practices during
processing
• Sorting followed by winnowing of naturally Infected Healthy
contaminated maize grains resulted in a mean
reduction of 59% and 69% in aflatoxin and
fumonisin levels, respectively (Fandohan et al.,
2005).
• Similar losses of aflatoxins (37%) and
fumonisins (51%) to wash water have been
reported when maize was processed into
derived products in Benin (Fandohan et al.,
2008)
• Small reductions in mycotoxin levels (18% for
aflatoxins and 13% for fumonisins) also have
been observed following lactic fermentation
when preparing ogi (fermented maize dough)
(Fandohan et al., 2005).
• A reduction of mycotoxin levels was observed
during the preparation of adoyo (86 % of
aflatoxins and 65 % of fumonisins). (Fandohan
in preparation)


Poverty reduction through a better
post harvest management of maize

aflatoxin levels in
100000
Maize sorting before

ppb
50000
storage resulted in
an important 0
Maize sorted Maize no-sorted
reduction of aflatoxin
level from 45461.22 experim ented technologies

ppb to 1811.775 ppb. Aflatoxin levels after six months

Calculated financial
losses were 40.75
FCFA for maize
sorted before
storage and 52.52
FCFA for non-sorted
maize.

Losses after six months

Atoxigenic Strain Identification
Toxin assay -
Unknown

Strain characterization cnx nia-D

VCG

Field Field release
Unknown
Competition assays
cnx
nia-D

Lab +

How does Biocontrol Work?
Soil
Sporulation on wet soil
colonization

3-20
days

Insects
Wind

Spores

Broadcast Inoculum on
@ 10kg/ha 20-30 sorghum grain carrier
days after sowing International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org

Steps in Aflatoxin Biocontrol R-4-D
• Collection and identification of isolates
• Characterisation of isolates
• Identification of atoxigenic strains
• Determination of genetic and molecular diversity in the
atoxigenic strains
• Ensuring biosafety of the atoxigenics
• Developing methods for mass multiplication of
inoculum for field application
• Testing efficacy of atoxigenics in field trials
• Sensitisation of growers, consumers and regulatory
agencies about potential of biocontrol
• Registration of the atoxigenic strains as biopesticides
• Upscaling and outscaling to wider areas

Awareness campaign & capacity building

More than 10 million
people in Benin, Togo
and Ghana are now
aware of the dangers of
aflatoxin-contaminated
feed/foods.

Per year:
About 10 students
1 training course on
post-harvest pests and
diseases
Individual training


Africa Conference

13-16 Sept 2005
Accra Ghana

 109 participants, 28 countries in Africa (15), Europe, Asia, North
America and South America
 Participants: Scientists, parliamentarians, heads of institutions,
policymakers, trade and health specialists


Impact of awareness campaign

Aflatoxin awareness amongst target groups before (Pre-C) and after (Post-C) awareness campaign in Benin, Ghana and Togo

Respondents aware of aflatoxin (%)

Awareness
Farmers Traders Consumers Poultry farmers
†
indicator
% % % %
Pre-C Post-C Pre-C Post-C Pre-C Post-C Pre-C Post-C
change change change change

Informed 20.8 53.2 32.4*** 26.7 56.9 30.2*** 25.2 63.5 38.3*** 60.0 60.9 0.9 ns

Believed 54.6 76.9 22.3*** 58.5 78.1 19.6*** 60.0 84.3 24.3*** 83.0 91.2 8.2 **

Adopts 51.1 75.7 24.6*** 55.4 91.8 36.3*** 81.3 84.5 3.2 ns 48.9 68.8 19.9***

James et al. 2007 Food Additives & Contaminants


Trade Losses due to Aflatoxins

• Export compliance with food safety Maize
and quality standards.
• Some countries active to meet Cocoa
standards by putting in place relevant
institutions
• Best quality exported; poorer quality
Coffee
consumed domestically.
• Need to evaluate the economic impact
of aflatoxin on health and trade, and the
economic benefit the deployment of
aflatoxin management can have.
Peanut

Nutritional status of children aged 18-36 month
in four agro-ecological Zones in Benin

Zone 1 (N=45)
Zone 2 (N=113)

38.56
% of undernourished children

37.01
45 Zone 3 (N=76)

32.18
31.58
30.13
40 Zone 4 (N=88)

28.12
27.44
27.6
35
30
25
20
15

4.41
3.93
10

7
5

0
0
Stunting Underweight Wasting

Figure 1: Prevalence (%) of malnutrition by agro-ecological zone

Honfo et al. to be submitted to International Journal of Food Safety, Nutrition and Public Health


Nutritional status of children aged 18-36 month
in four agro-ecological Zones in Benin

Zone 1(N=45)
100

78.2
Zone 2 (N=113)

71.9
64.3
62.3

61.9
60.5

80 Zone 3 (N=76)

55 .6
48 .9

52.5
51.3
Proportion

60 Zone 4 (N=88)
37 .8

36.8
40
20
0
Energy Proteins Iron
Figure 2: Proportion of children covering at least 100% of the nutritional
needs
Honfo et al. to be submitted to International Journal of Food Safety, Nutrition and Public Health


Summary

• Food supplies in Africa are precarious
• High losses of foods both in Quality
(mycotoxins, chemical residues,
hygiene) and in Quantity (mostly due
to pest)
• Need for improved storage structures
and methods to reduce these losses
(up to 30%)
• Need improved access to markets
• Need improved processing and
packaging methods to maintain quality

It’s not possible that people go hungry
and we have more than 30% of the
children showing signs of malnutrition


New research opportunities
• Quality in horticultural food chains (risk
assessment, technology options)
• Scaling up and out of mycotoxin management
using different partnership models
• Economic impact of mycotoxin management on
improved health and income
• Study other mycotoxins eg. Fumonisin,
OchratoxinA (diagnostic capacity has to be
established)
• Mycotoxins and climate change
• Monitoring and testing of product quality at
different steps in commodity chain using
appropriate analytical tools (mycotoxins,
pesticide residues, other microbes)
• Development of options for quality approaches &
Market Access (Technologies, Methodologies,
Training)
• Food/nutrition/health especially focusing on child
health

Postharvest and Food Safety Management for Improved Health and Income

Recommandé

Recommandé

Contenu connexe

Similaire à Postharvest and Food Safety Management for Improved Health and Income

Similaire à Postharvest and Food Safety Management for Improved Health and Income (20)

Plus de International Institute of Tropical Agriculture

Plus de International Institute of Tropical Agriculture (20)

Dernier

Dernier (20)

Postharvest and Food Safety Management for Improved Health and Income