5. IMPORTANCE OF FOOD STORAGE
⚫ Storage is the art of keeping the quality of agricultural materials and
preventing them from deterioration for specific period of time, beyond
their normal shelf life.
Why is important to store the food??
Provision of food materials all year round
Pilling/provision for large scale processing
To extend to optimum shelf life and maintain quality
Price control and regulation/market fluctuation/Later sale
Optimization of farmers gain/financial empowerment of
farmers
To use at the time of famine/Famine reserve
Opportunity for export market,
Buffer stock etc
7. Storage of perishable crops
The term "storage” is to mean the holding of fresh fruit
and vegetables under controlled conditions.
Only crops with high initial quality can be stored
successfully;
mature, and undamaged
stored at cool temperature and in well ventilated room
proper fruit and vegetables storage practices include:
temperature control,
relative humidity control,
air circulation and maintenance of space between containers for
adequate ventilation, and
avoiding incompatible product mixes
8. Storage of perishable crops
Commodities stored together should be capable of
tolerating the same
temperature,
relative humidity and
level of ethylene in the storage environment.
12. Cont
…..
Refrigerated storage
⚫It is the storage method that termed as cold storage
system
o lowers temperatures when ambient conditions are
warm.
⚫An evaporative cooling system is used to reduce air
temperature and to remove moisture.
⚫Cold storage can also be used for long-term storage of
seasonal crops such as potatoes and onions.
14. CAS and MAS
CAS and MAS is a system for holding produce in an
atmosphere that differs from normal air
In respect to CO2 and O2 levels.
They Work by regulating the concentrations of
oxygen, carbon dioxide and nitrogen,
temperature and humidity of a storage room.
The gas mixture may constantly change due to
metabolic activity of the respiring and
leakage of gases through doors and walls.
15. Modified Atmospheric storages of F & V
⚫ MAS is the practice of modifying the composition of the
internal atmosphere of a storage
⚫ The modification process conducted by:
⚫lowering the amount of O2, from 20.9% to 1-3%,
⚫Increasing the amount of CO2 from 0.05% to 2-20%
•No control way over the process
•gas composition changes due to:-
activities such as product respiration
diffusion of gases into and out of the
product,
15
16. Controlled atmosphere storage (CAS)
⚫ It is a storage method in which the concentrations of O2
and Co2 is controlled to pre-determined condition
⚫ It refers to the constant monitoring and adjustment of the Co2
and O2 levels within gas tight stores or containers.
⚫ CAS storage involves
⚫reducing oxygen from 20.9% to 1-3%,
⚫Increasing carbon dioxide from 0.05% to 2-20%
⚫removing ethylene and other volatiles,
⚫as well as maintaining temperature and humidity.
• gases should be measured periodically and adjusted to the
optimum concentration
•control way over the process
17. Ventilated storage
⚫ The aims of this type of storage are to offer protection
against
⚫fungus growth and rotting by providing ventilation
⚫Ethylene production
⚫Gas composition disturbance
⚫ This storage method is suitable for storing root crops.
20. Cont…..
Zero Energy Cool Chamber-storage type
⚫Works by making two layer walls filled a moist sand in
between the walls
⚫It should be covered by roof from the top
⚫there is no need for electrical and mechanical energy for
the functioning
⚫Works based on the principles of direct evaporative
cooling
⚫Evaporative cooling is the reduction in temperature
resulting from the evaporation of a liquid, which removes
latent heat from the surface from which evaporation
takes place.
⚫Well constructed ZECC stored tomato
⚫for 33 days without any negative response to the
produce
176
23. Types of Storage Facilities
Traditional storage facilities
⚫Clay pots
⚫Bags/sack
⚫Traditional metal drums and bins
⚫Baskets
⚫Bins of stone or mud plaster
⚫Underground pits
Advantages:
⚫Made from local materials, hence cheap.
⚫Do not require technical skills
Disadvantages:
⚫Rats and weevils can attack.
⚫Rotting of grains
⚫Limited in size
179
25. Improved/Modern Storage Facilities
Improved storage methods
⚫Metal Silos
⚫Ventilated storage structures
⚫Airtight (hermentic) storage (oxygen and moisture proof)
Metal silo ventilated storage gas & moisture proof liner
26. Improved/Modern Storage Facilities
Advantages:
⚫Long life span
⚫Rodent proof
⚫Can store large quantities of grain
⚫Easy to maintain
Disadvantages:
⚫Quite expensive to construct
⚫Requires technical skills to design/erect
27. Cont.…
Factors Influencing the Choice of Storage Facilities:
⚫The quantity of produce to be stored
⚫The period or duration of storage
⚫Availability of construction materials
⚫The cost of construction
28. Types of Storage Facilities
1. On the Ground/On-farm storage systems
piled on the ground and unprotected only between
harvest and the availability of transport equipment
grain is exposed to rodents, birds, insects, and wind
pile should be on high ground
drainage is a crucial factor
30. 2. Bagged Storage
• This is a very popular form of storage.
• Bagged grain can be stored in almost any shelter that
protects the bags from weather and predators
• The bag should never rest directly on the ground or
against walls
Advantage of bagged storage
• lower capital costs without any need for sophisticated
aeration and fumigant circulation facilities
• easy to handle and allows you to store different grains
in the same room.
31. Cont….
The main disadvantage of bag storage is that the bag does
not provide protection against rat or insect attack.
32. 3. Bulk Storage
• most widely used type of storage
• Bins are constructed of steel, aluminum, concrete, and even
wood or plywood/basket.
• Round bins are most common,
• flat storage buildings are also used as well
32
33. Bulk Storage
Advantage
Can handle much grain in one storage structure
Can provide protection against rodent and birds
Disadvantage of bulk storage
Formation of charring and caking on grains
Cannot provide protection against insect attack
The modern may be expensive
34. 4. Underground storage
⚫ This method of storage is used in dry regions where the water table
does not endanger the contents.
⚫ Underground pit is a special form of a closed storage system and is a
promising method of storing grain
⚫ It is an effective, low cost method of long-term storage
–in good condition more than 10 years
– pits vary in capacity (from a few hundred kg to 200 tones).
⚫ It is characterized by low oxygen levels and prevent development of
damaging numbers of grain insects
⚫ Grain moisture content must be less than 12%
35. Cont.….
⚫ Underground pit varies from region to region: they are usually
cylindrical, spherical or amphoral in shape
⚫ The entrance to the pit may be closed either by sand onto a timber
cover, or by a stone sealed with mud.
36. Cont….
Advantages of underground pit storage:
⚫few problems with rodents and insects if only properly dried
grain and moisture ingress is prevented
⚫low cost of construction compared to that of above-ground
storage of similar capacity
⚫ambient temperatures are relatively low and constant;
⚫hardly visible, and therefore relatively safe from thieves;
⚫no need for continuous inspection
37. Cont….
⚫ The disadvantages are:
⚫construction and digging are laborious;
⚫storage conditions can adversely affect viability
⚫the grain can acquire a fermented smell after long
storage
⚫removal of the grain is difficult and can be dangerous
because of the accumulation of carbon dioxide in the
pit, if it is not completely full;
⚫inspection of the grain is difficult;
⚫Risks of penetration by water are not small, and the
grain at the top and in contact with the walls is often
mouldy, even if the rest of the stock is healthy.
39. Airtight storage
⚫Hermetic storage technology is airtight storage
structure.
⚫It works based on the principle of generating
⚫an oxygen-depleted,
⚫carbon dioxide-enriched interstitial atmosphere caused
by
⚫ the respiration of the living organisms in the ecological system
of a sealed storage structure
• elimination of the oxygen and an increase of the carbon
dioxide level.
40. Airtight storage
⚫A more popular form of hermetic storage system is the
triple layer bag
⚫ it consists of a sealed storage system containing a modified
atmosphere.
⚫ If a container is filled with grain and then hermetically
sealed (made airtight),
⚫the living organisms inside soon use up the available
oxygen and then they suffocate and die.
⚫E.x. Sitophilus is suffocated when oxygen is reduced
to 2%.
43. Ventilated storage
⚫ The aims of this type of storage are to offer protection
against
⚫ rodents, sun, rain and ground water
⚫ to prevent fungus growth and rotting by providing ventilation
⚫ It offers hardly any protection against insects,
⚫ it is less suitable for long term storage of cereals and pulses.
⚫ This storage method is suitable for storing root crops.
⚫ for protection against rats and termites, the huts can be
built on poles, at least 75 cm in height with rat baffles
fixed on them.
46. Refrigerated grain storages
⚫ It is the storage method that termed as cold storage
system
⚫lowers temperatures when ambient conditions are warm.
⚫ Mostly used in tropical climates
⚫ It can be justified for storage of grains such as
⚫malting barley
⚫seed grains in hot conditions, where maintenance of
germination viability is important.
⚫designed specifically for markets where food safety
and security are important
⚫ An evaporative cooling system is used to reduce air
temperature and to remove moisture.
48. CAS and MAS
CAS and MAS is a system for holding produce in an
atmosphere that differs from normal air
In respect to CO2 and O2 levels.
They Work by regulating the concentrations of
oxygen, carbon dioxide and nitrogen,
temperature and humidity of a storage room.
The gas mixture may constantly change due to
metabolic activity of the respiring grains and
leakage of gases through doors and walls.
49. CONTROLLED ATMOSPHERE STORAGE
⚫ It is a storage method in which the concentrations of O2,
Co2 and N2 is controlled to pre-determined condition
⚫ It refers to the constant monitoring and adjustment of the
Co2 and O2 levels within gas tight stores or containers.
⚫ The gases should be measured periodically and adjusted to
the optimum concentration of predetermined level by
⚫the introduction of fresh air or nitrogen or CO2.
50. CA Storage
⚫ Controlled-atmosphere (CA) storage of grains includes
⚫commodity-modified CA storage and
⚫artificially modified CA storage
⚫ Commodity-modified storage, respiration of grain & MO’s
reduces O2 and increases CO2.
⚫ Artificially modified CA storage--by injecting N2 or CO2
⚫ Traditional underground pit storage is an example of sealed
commodity-modified CA storage; ideally,
⚫the O2 decreases to 0.2% - 0.5% and
⚫the CO2 increases to 45% - 50%.
52. Modified Atmospheric storages of grains
⚫ MAS is the practice of modifying the composition of the
internal atmosphere of a storage
⚫ The modification process conducted by:
⚫lowering the amount of O2, from 20.9% to 0%,
- to slow down the growth of aerobic organisms and
- prevent oxidation reactions.
⚫Replacing the removed O2 with
⚫nitrogen (N2), or
⚫carbon dioxide (CO2), which can lower the pH or
inhibit the growth of mos. and insects
53. Cont….
⚫ In MAS after atmosphere composition adjustment
⚫No control way over the process
⚫gas composition changes due to activities such as
product respiration
54. THANK YOU
FOR YOUR ATTENSION!
Next class we will try to see
CHAPTER 7
SIZE REDUCTION
