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What is
aflatoxin?
Many agricultural commodities are
vulnerable to attack by a group of fungi that produce toxic metabolites called
mycotoxins. Among these mycotoxins, aflatoxins have assumed significance due to
their harmful effects on human beings, poultry and livestock. Two species of
fungus Aspergillus flavus (predominant in Asia and Africa) and Aspergillus
parasiticus (mostly found in the Americas), produce aflatoxins on various food
products. One of the most dangerous aflatoxins finds its way into the milk
systems of animals who have consumed contaminated feed (usually groundnut cake
or haulms with small pods). This is called aflatoxin M1.
• Alfatoxin is carcinogenic and can
cause liver and other cancers in humans.
• It is synergistic with hepatitis
viruses B and C.
• It lowers the body’s normal immune
response to invasion by foreign substances.
• It impairs growth in children,
notably in Africa, and causes childhood cirrhosis in India.
• In poultry and livestock,
aflatoxin can cause feed refusal, loss of weight, reduced egg production and
contamination of milk.
Infected Pods
Factors
contributing to contamination in groundnut
Postharvest
• Harvesting an overly mature crop.
• Mechanical damage to the pod at
the time of harvest.
• Stacking the harvest when pod
moisture is more than 10% or under high humidity conditions.
• Damage to the pod by insects
during storage.
• Storing haulms with immature or
small pods (they tend to contain more aflatoxins).
• Gleaning pods from the soil after
harvest.
• Rewetting stored pods due to
factors like ground-moisture or roof leakage.
Preharvest
• Presence of the A. flavus fungus
in soil and air. This infection of groundnut, which occurs at every stage from
preharvest to storage, causes aflatoxin production in the kernels.
• Use of susceptible cultivars.
• End-of-season moisture stress to
the crop for more than 20 days.
• Mean soil temperatures of 28-31oC
in the pod zone.
• Growth cracks and mechanical
injury to the pod.
• Insect damage to pods by termites
or pod borers.
• Death caused by diseases (stem,
root and pod rots) at pod maturity stage.
• Nematode damage to the pod.
Postharvest yard stacks
How can
aflatoxin be contained?
Preharvest
• Use aflatoxin-resistant groundnut
varieties.
• Select sound seed and treat them
with Diathane M45 (@ 3g/kg) before planting.
• Apply farm yard manure/compost @
5-10 tons/ha.
Different Pod Sizes
• Apply Trichoderma @ 1kg/ha.
• Maintain optimal plant population
in the field (33 m2).
• Apply gypsum (@ 400-500 kg/ha) at
flowering.
• Avoid end- of- season drought with
irrigation, if possible.
• Control foliar disease using
Kavach with 1-2 sprays.
• Remove dead plants from the field
before harvest.
• Harvest the crop at right
maturity.
Postharvest
Pods are frequently damaged during harvest
• At harvest, avoid mechanical
damage to the pod by inserting the blade or plow below the pod zone.
• Dry the harvested produce for 3-5
days using the inverted wind row drying method.
• Dry the produce until the pod
moisture is below 8%.
• Strip or thresh the pod
immediately after drying. Avoid stacking.
Border-damaged pods
• When using mechanical threshers,
use appropriate sieves based on pod size so that immature pods are blown off.
• Remove mechanical- and
insectdamaged pods.
• Separate the fully mature large
pods (to be used for raw consumption) from the remaining produce (used for oil
extraction).
• Do not mix the gleaned pod with
the main produce.
• If necessary, dry the stripped/
threshed pod once again to maintain seed moisture below 8%.
• Stack the pod-filled gunny bags on
a wooden plank and store them in well aerated, waterproof storage.
• Prevent insect damage to the pods
in storage.
Growth Cracks on Groundnut Pods
• Remove all immature pods attached
to the haulms.
Food products
susceptible to aflatoxin contamination
• Cereals: maize,
sorghum, pearl millet, rice, wheat
• Oilseeds: groundnut,
soybean, sunflower, cotton
• Spices: chilli,
black pepper, turmeric, coriander and ginger
• Nuts: almond,
pistachio, walnut, coconut
• Milk and milk products
How aflatoxin
affects groundnut
• Causes marked deterioration in
kernel quality because of fungal growth. Contaminated kernels are then unfit
for the markets or for consumption.
• Causes decay in both seeds and
non-emerged seedlings and leads to aflaroot disease.
• Severely affects the export of
groundnut and its products.
Project Partners:
 Acharya
N G Ranga Agricultural University. Society for Transformation,
Agriculture
and Alternatives in Development.
University
of Reading, U.K.
Rural
Development Trust.
Intergrated
Rural Development Trust.
Printed flyers
are available in English, Hindi, Telugu and French
International Crops Research
Institute for the Semi- Arid Tropics Patancheru 502 324, Andhra Pradesh, India
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