safety precaution to maintain grain quality - implementer induction training

www.iita.org A member of CGIAR consortium Date: 19-June-2014

Safety Precaution to Maintain Grain

Quality

Lawrence K. Kaptoge

Adebowale Akande

Joseph Atehnkeng

Joao Augusto

Ranajit Bandyopadhyay


Introduction – Health & Economic Losses

• The 2004 outbreak (317 cases reported, with 125 deaths) resulted from widespread

aflatoxin contamination of locally grown maize, which occurred during storage of the

maize under damp conditions. Aflatoxin poisoning likely will continue to be a public

health problem until culturally appropriate storage methods for dry maize are

implemented by the local population

• Evidence that this outbreak resulted from aflatoxin poisoning included:

1. High levels of aflatoxin (up to 8,000 ppb) in maize samples collected from patient

households

2. Clinical illness consistent with acute aflatoxin poisoning

3. Clustering of cases among residents of the same household and

4. Reports of deaths among animals known to have eaten the same maize as the

patients during the same period.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5334a4.htm.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5334a4.htm


Introduction – Health & Economic Losses


Introduction

Small-scale grain

farmers in Kenya risk

losing out from the

World Food Program

maize purchase deal

due to contamination

of grain by aflatoxin.

On Tuesday, the

government raised

the red flag after

samples from last

season’s harvest

were found to be

contaminated.

http://www.nation.co.

ke/business/Aflatoxin

-to-hurt-farmers-

prospects-/-

/996/918918/-

/f07g2c/-/index.html

http://www.nation.co.ke/business/Aflatoxin-to-hurt-farmers-prospects-/-/996/918918/-/f07g2c/-/index.html




































Introduction

• The National Cereals and Produce Board has re-opened its depots in Eastern and Coast

provinces to buy maize with aflatoxin. A major alert was issued by the government last week in connection with 2.3 million bags of contaminated maize in the two provinces. http://www.nation.co.ke/news/Cereals-board-moves-to-buy-bad-maize--/-/1056/934812/-/5y2gn3/-/index.html

• Change of fortunes as sweet harvest turns suddenly sour

Tests reveal that slightly over 60 per cent of the maize tested in the larger Makueni District is infected with the poisonous aflatoxin. http://www.standardmedia.co.ke/article/2000010754/change-of-fortunes-as-sweet-harvest-turns-suddenly-sour

http://www.nation.co.ke/news/Cereals-board-moves-to-buy-bad-maize--/-/1056/934812/-/5y2gn3/-/index.html





















http://www.standardmedia.co.ke/article/2000010754/change-of-fortunes-as-sweet-harvest-turns-suddenly-sour

















• Highly toxic metabolite produced by the ubiquitous Aspergillus flavus fungus

• The fungus infects crops and produces the toxin in the field and in stores

• Fungus carried from field to store

• Contamination possible without visible signs of the fungus

• Some predisposing factors: – pre-harvest high temp and

drought stress

– wet conditions at harvest and

post-harvest periods

– insect damage

Aflatoxin Facts


Out line

• Sampling.

• Moisture content

• Fumigation.

• Drying.

• Cleaning.

• Storage

• Steps for good storage practices


Out line

Sampling is important for checks and testing for a range of

properties; moisture content, infestation viability, weight etc.

• Done periodically to check on the viability and general

deterioration of the crop.

1. In the field to determine MC, maturity, infestation etc.

2. On arrival at the store for MC, infestation, quantity etc

3. During storage for continual quantity monitoring

4. On despatch from store where it is weighed out and samples

retained in event of subsequent disputes

5. On arrival at the purchaser’s store for required quality attributes.


Sampling

Sampling points: A 5; B 8; C 11.

http://www.cd3wd.com/cd3wd_40/INPHO/VLIBRARY/T0522E/GIF/T0522E0D.GIF


Aflasafe sampling – Raw Sorghum

Consignme

nt Date/

2014

# Bags

Registers

Clean Grain

(kg)

Waste

Material

(kg)

Total of

Grain (kg)

% of Grain

(kg/Bag)

09/05 310 26,265.0 1988.5 28,253.5 91.5

10/05 303 24,451.00 2,533.00 26,984.00 89.0

22/05 320 29,055.00 1,453.00 30,508.00 95.5

TOTAL 933 79,771.00 5,974.50 85,745.50 92

% of grain 93 % 7 % 100 %


Aflasafe sampling – Raw Sorghum

Consignment Date/

2014

# Bags with high

fungus contamination

Total of Grain (kg)

09/05 7 655.0

10.05 4 354.0

22/05 3 285.0

TOTAL 14 1,294.0

Finished Product – every 100 packets I sample collected


Sampling


Fumigation

• Fumigation - method of pest control that completely fills an area with gaseous pesticides

or fumigants to suffocate or poison the pests within.

• Used for control of pests in buildings (structural fumigation), soil, grain, and produce & during

processing of goods to be imported or exported to prevent transfer of exotic organisms.

• It involves:

• Covering the area to be fumigated to create a sealed environment;

• Releasing of fumigant into the space to be fumigated;

• Holding the pace for set period while the fumigant gas percolates through the space and

acts on and kills any infestation in the product and finally

• Ventilation of the space to allow poisonous gases escape and render it safe for entry.

• If successful, the fumigated area is now safe and pest free.

• Widely used fumigants include:

o phosphine

o 1,3-dichloropropene

o chloropicrin

o methyl isocyanate

o hydrogen cyanide

o sulfuryl fluoride

o formaldehyde

o Iodoform

http://en.wikipedia.org/wiki/Pest_control



http://en.wikipedia.org/wiki/Pesticide

http://en.wikipedia.org/wiki/Introduced_species



http://en.wikipedia.org/wiki/Infestation

http://en.wikipedia.org/wiki/Poison



http://en.wikipedia.org/wiki/Phosphine

http://en.wikipedia.org/wiki/1,3-dichloropropene





http://en.wikipedia.org/wiki/Chloropicrin

http://en.wikipedia.org/wiki/Methyl_isocyanate



http://en.wikipedia.org/wiki/Hydrogen_cyanide



http://en.wikipedia.org/wiki/Sulfuryl_fluoride



http://en.wikipedia.org/wiki/Formaldehyde

http://en.wikipedia.org/wiki/Iodoform


Fumigation


Moisture Content

Moisture content

Definition

It is the amount of moisture (water) the seed contains.

2 methods of expressing moisture content:

1. Wet Basis

2. Dry Basis

Moisture content determination methods:

1. Direct methods determine the amount of water in the seeds

by removing them.

2. Indirect methods require the use of a meter to measure the

property of the seed that can be related to the moisture

content


Moisture Content

Source: Transactions of ASABE 3330337


Drying

o Physiological maturity - high moisture e.g. maize 35 %, highest quality, greatest vigour and germination potential.

o Duration of safe storage dependent on the condition the crop was harvested and the type of storage facility being utilized.

o Drying - Removal of high moisture to low levels for safe storage. Drying, Aeration and Dehydration. Drying permits a reduction of losses in storage from causes such as:

• Premature and unseasonable germination , • Development of moulds, • Proliferation of insects.

Recommendation: Harvesting early MC >20%, quickly dry to safe MC <13%.

Drying may be effected by any of the following methods:

1. Field drying

2. Sun drying

3. Drying with forced artificially heated or unheated air,

4. Use of desiccants to dehumidify the air and

5. Drying with infrared light rays.


Drying

Reasons for drying.

o Retard or stop the development of bacteria, fungi, mites and

insects during storage.

o Make further processing easier.

o Prevent germination.

o Produce uniformly high quality crop/seed with high vigour and

germination.

o Reduced damage in processing operations, especially in

shelling in the case of maize, to elevators and cleaners.

o Increased quality of harvested grain by reducing crop

exposure to weather.

o Harvesting can be done early and in a controlled way.

o Harvesting operations can be scheduled to obtain more

efficient use of labour and available equipment.

o Allows more time for post-harvest fieldwork.

o Reduced potential for weather and pest related field losses.


Importance of drying

http://www.nation.co.ke/news/regional/Sh760m-given-to-fight-maize-poisoning-/-/1070/936196/-/h322gm/-/index.html







































Drying


Cleaning

• After threshing, grains (or shells, in the case of groundnuts) are contaminated by

impurities (earth, small pebbles, plant and insect waste, seed cases, etc.)

• These impurities hinder drying operations and make them longer and more costly.

• Traditional methods: Simplest cleaning method, known as winnowing, consists of

tossing the grain into the air and letting the wind carry off the lightest impurities.

• Although widespread does not eliminate all impurities.

• Air Screen Cleaning:


Storage

• Storage - produce kept in condition to guarantee food security other than during periods of agricultural production.

• Main objectives of storage:

i. At the food level – use on annual/multiannual

ii. At the agricultural level –Availability of seed for crop cycles to some

iii. At the agro-industrial level - guarantee regular and continuous supplies of raw materials for processing industries;

iv. At the marketing level - to balance the supply and demand of agricultural products, thereby stabilizing market prices.

• To attain above general objectives, necessary to adopt measures aimed at preserving the quality and quantity of the stored products over time.

• Storage in bag or bulk; sealed or unsealed structure.

• Effect of environmental factors and Agents causing deterioration – microorganisms, insects and rodents


Storage

• Influences of environmental factors

• long-term storage, degradation processes must be slowed down or even

stopped.

• Degradation of grains during storage depends principally on a

combination of three factors:

o Temperature,

o Moisture,

o Oxygen content.

• Temperature and moisture

• Direct influence on the speed of development of insects and

microorganisms (moulds, yeasts and bacteria), and on the premature

and unseasonal germination of grain.

• Moisture content of stored grain, depends on the relative humidity of the

air,

• Temperature sensors in silos


Storage

• Oxygen content

• Like grain, micro-organisms and insects are living organisms that need

oxygen. Storage of grain in places that are low in oxygen causes the

death of insects, cessation of development of micro-organisms, and

blockage, or slowing down, of the biochemical phenomena of grain

degradation. This favours the conservation of grain, but may affect its

germinating power. CA Storage.

• PICS bag storage - Purdue Improved Crop Storage (PICS2) - http://www.entm.purdue.edu/PICS2/

http://www.entm.purdue.edu/PICS2/


Steps for Good Storage Practice


Agents causing deterioration of

stored grain • The principal enemies of stored grain are micro-organisms, insects and

rodents.

• Micro-organisms

• Micro-organisms (moulds, yeasts, bacteria) are biological agents present

in the soil which, when transported by air or water, can contaminate

products before, during and after the harvest.

• Their presence and growth cause severe changes in the nutritive value

and the organoleptic features of grain (taste, smell, aspect).

• They are responsible for formation of dangerous poisons.

• Impurities and cracked or broken grains, foster the development of

micro-organisms.

• Temperature and humidity have a determining influence on the growth

rate of these degradation agents.

• On the contrary, atmospheres that are low in oxygen help check the

development of these degradation agents.


Agents causing deterioration of

stored grain Insects

• Insect infestations occur either in the field, before harvest or in storage.

• Their biological activity (waste production, respiration, etc.) compromises

the quality and commercial value of the stored grain and fosters the

development of micro-organisms.

• Insects can live and reproduce at temperatures between 15 & 35 0C.

• Low humidity slows or even stops their development, and a low supply of

oxygen rapidly kills them.

Rodents

• Rodents invade and multiply in or near storage places, where they can find

abundance of food. They also cause serious damage to packaging and

storage buildings.

• Prolonged attacks result in serious quantitative losses of stored products.

• Their filth (excrement, secretions) is responsible for decrease in quality of the

foodstuffs

• This contamination is as important from the marketing standpoint as it is for

hygiene and health. Rodents are often the vectors of serious diseases

(rabies, leptospirosis).


Good Post Harvest Practices

For best storage performance:

• Clean the grain to remove chaff, weed seeds, and broken kernels

• Handle grain gently to minimize cracked and broken kernels.

• Dry to the safe storage moisture 10-12 % for cereals; 7-9% for oil seeds

• Aerate to maintain cool, uniform recommended temperature.

• Properly clean and disinfect the storage structures.

• Chose storage structure that does not permit contact/exchange with

outside humid air.

Requirements for good storage

• Provide maximum possible protection from ground moisture, rain, insect

pests, moulds, rodents, birds etc.,

• Provide the necessary facility for inspection, disinfection, loading,

unloading, cleaning and reconditioning.

• Protect grain from excessive moisture and temperature favourable to

both insect and mould development.


Ideal Storage Conditions


Ideal Storage Conditions

Figure 2. Storage Risk Increases with Temperature, Moisture and Time.



Pests Stored product pests can be managed either behaviouraly (traps ) or with

several preventive and curative measures (both chemical and non-

chemical methods).

Steps.

1. Before storage

• Check for leakage of rain water and sufficiency of drainage facilities

• Cleanliness of the facility and environment

• Pesticidal treatment – e.g. application of Actellic dust

• Security and fire fighting arrangements and

• Repairs to available equipment

2. After receipt

• Inspection for variety and soundness of quality

• Carefully inspection for infestation and when present, type and extent of

infestation,

• Inspection whether grain has excess moisture, any grain rendered wet or

damaged to be segregated and salvaged with facilities available and

check the weight received



3. During storage

• Maintenance of cleanliness

• Ensuring aeration where necessary

• Check for leakage after rains

• Inspection for insects, rats and mites at fortnightly intervals

• Watch for advancement in deterioration, if any,

• Arrangement for segregation, salvage and processing, wherever,

damage owing to leakage of water and other causes might have

taken place.

www.iita.org A member of CGIAR consortium Date: 02 – May - 2013

http://www.aflasafe.com/

http://www.iita.org/

safety precaution to maintain grain quality - implementer induction training

Science

aflatoxin poisoning

maize samples

dry maize

acute aflatoxin

poisonous aflatoxin

bags of contaminated

high levels of aflatoxin

sweet harvest