1. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
3.5 HANDLING, TRANSPORTATION AND STORAGE OF FOODS
DETAILED CONTENTS
1. Introduction (03 hrs)
Scope and importance of handling, transportation and storage of food and food products, post harvest
losses
2. Post Harvest Changes in Foods – Physiological, chemical, microbiological and biochemical (06 hrs)
3. Handling, Transportation and Storage (08 hrs)
Various unit operations of post-harvest handling, transportation, introduction to different conveying
systems like belt conveyors, chain conveyors, screw conveyors, hydraulic conveyors, pneumatic
conveyors, vibrating and oscillating conveyors, bucket elevators – their selection, operation and
maintenance.
4. Grains (08 hrs)
Preparation of grains for storage, Storage requirements, infestation control, mycotoxin, handling practices,
causes of spoilage and their prevention, factors affecting quality of grain during storage and types of
storage structures and facilities
5. Fruits and Vegetables (05 hrs)
Handling, transportation and storage, spoilage and prevention
6. Animal Foods (07 hrs)
Pre-slaughter handling and transportation system – their effects on quality of meat products, transportation
and storage requirements, ante-mortem examination of animals
7. Milk (03 hrs)
Collection, pre-cooling, handling and transportation systems – their effects on quality of milk
8. Eggs (03 hrs)
Candling and grading, packaging, handling, pre-treatment, transportation and storage
9. Cold Storage (05 hrs)
Introduction to cold storage facilities & requirements for storage of different fruits and vegetables.
LIST OF PRACTICALS
1. Sampling Techniques of stored foods from different storage structures and conditions
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2. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
2. Analysis of sampled grain for foreign matter like straw parities, rodent excreta and rodents & insects
infected grains
3. Demonstration of changes during storage of fresh fruits and vegetables in (a) traditional storage (b)
modified storage system (c controlled atmosphere
4. Determination of changes in pH and acid values in storage of milk
5. Visit to a public distribution system (PDS) showing storage facilities, warehouse, cold storage,
refrigeration system and slaughter house etc
6. Visit to demonstration of material handling systems in various food industries
1. Visits to cold storage
INSTRUCTIONAL STRATEGY
Teachers should prepare tutorial exercises for the students, involving visits to various food-processing units. These
tutorials can be considered a mini projects. Students may be asked to bring specifications and catalogues from
industries. Students may also be exposed to relevant National, BIS and international standards. An intensive
exercise on actual workbench performance in the industries is recommended. Experts may be invited to deliver
lectures on various themes. Use of audio-visual aids will also be useful for better conceptualization of various
operations.
RECOMMENDED BOOKS
1. Handling, Transportation and Storage of Fruits and Vegetables by A Lloyd, Ryall Penizer (AVI
Publications)
2. Proceedings of Regional Workshop on Warehouse Management of Stored Food Grains by Girish and
Ashok Kumar (UNDP)
3. Modern Potato and Vegetable Storage by Volkind and Roslov (Amerind)
4. Controlled Atmospheric Storage of Fruits by Mettel Skilv
5. Food Grains in Tropical and Sub Tropical Areas by Hall
1. Food Storage Part of a system by Sinha and Muir (AVI)
2. Post Harvest Technology of Fruits and Vegetables – Handling, Processing, Fermentation and Waste
Management by LR Verma and VK Joshi; Indus Publishing com., New Delhi
3. Drying and Storage of Grains and Oilseeds by Brooker & Hall, CBS
SUGGESTED DISTRIBUTION OF MARKS
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3. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Topic No. Time Allotted (Hrs) Marks Allotted (%)
1 3 6
2 6 12
3 8 16
4 8 16
5 5 12
6 7 16
7 3 6
8 3 6
9 5 10
Total 48 100
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4. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Fruits and Vegetables play an important role in agriculture, human health and national economy. India is the
second largest producer of fruits and vegetables in the world. India produces about 100,000 corers of rupees worth
fruits and vegetables every year. However, a considerable amount of this produce in lost due to negligence and
improper post harvest handling, which amounts to be 25 to 30%.
In spite of huge production, India shares only 2.3% of the world trade of fruits and vegetables. It also
process only 2.5% of the total produce in a organized sector whereas Thailand 30%, Brazil 70%, Philippines 78%
and Malaysia 80%.
Fruits and vegetables processing industry ranks 5th in its size and employees 19% of work force which is
about 1.6 million people. It accounts for 14% total industrial output against 5.5% industrial investment and
contribute 18% to the GDP. Annual turnover of fruit and vegetable industry is Rs. 1800 billion and out of which
Rs. 1400 billion are from unorganized sector.
FACTORS CAUSING SPOILAGE: PHYSICAL, THERMAL, MICROBIAL, CHEMICAL, INSECTS,
PESTS, DISEASES
The perishable foods like fruits and vegetables continue to undergo chemical changes even after harvest. The
changes of fruits after harvest are numerous. Some of the very important changes include changes in
• rate of respiration
• water content
• carbohydrates
• Organic acids and pH.
Factors causing spoilage often do not operate in isolation. At one time, many forms of deterioration may take
place, depending on the type of food and the environmental conditions that its exposed to.
Physical Factors
Storage conditions like temperature, oxygen, light, duration of storage etc are the important factors that influence
the type of microbial growth and spoilage. Abnormal physiological deterioration occurs when fresh produce is
subjected to extremes of temperature, of atmospheric modification or of contamination. This may cause
unpalatable flavours, failure to ripen or other changes in the living processes of the produce, making it unfit for
use.
Microbial Factors
Bacteria, yeasts and moulds often cause food spoilage after harvesting, during handling, processing and storage.
They attack all the food components – sugar, starch, cellulose, fat and protein. Depending on the food and the
microorganisms, the action on food could be to produce acids, making the food sour, or produce alcohol. Some
microorganisms produce gases, making the food foamy; still others produce unwanted pigments or toxins.
Chemical Factors
Pesticides can leave residues on plant produce much more than safe limits and make them unfit for consumption.
Poisonous chemicals may enter foods from utensils. The rate of a chemical reaction doubles itself for every 100
C
rise in temperature. Excessive heat results protein denaturation and destruction of vitamins. Several fruits and
vegetables deteriorate even at refrigeration temperature (40
C) resulting in discoloration, changes in texture etc.
Indiscriminate use of all plastic packaging material like polyvinyl and polyethylene material can be a health
hazard, e.g., it may lead to the reaction of acid and oil of pickles with plastic packaging as observed in some cases.
Insects, Pests, Diseases
Insects, worms, bugs and fruit flies may damage foodstuffs such as grains, fruits and vegetables and render them
unfit for consumption. Pests such as rodents introduce high degree of filth in form of excreta, bodily secretions and
spoilage microorganisms. For example, rats can transfer the bacteria Salmonella to the food, may cause
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5. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
salmonellosis. Several types of pathogenic fungi are able to initiate an infection on the surface of floral parts and
on, developing fruits.
POST HARVEST TREATMENTS
In our country the most (above 97%) of the horticultural produce is consumed as fresh. The post harvest handling
involves movement of the horti produce from field to the dining table. This may be in bulk or retail. The better
quality, produce fetches better returns. Therefore, the quality of produce is to be maintained by keeping a close eye
on the movement of the produce. Fruits and vegetables continue to respire even after harvesting.
On-farm post harvest treatments are basically into two:
1. Removal of field heat by cooling
2. Disinfections of the produce
We cannot improve the quality of the harvested commodities but it can be retained till consumption if the
rate of metabolic activities is reduced by adopting the appropriate post harvest handling operations:
1. Pre-cooling
Cooling of fresh produce means removal of the field heat. Harvesting/picking should be done in the early
morning or late evening during low temperature”. Pre-cooling (prompt cooling after harvest) is important for
most of fruits and vegetables because they may deteriorate as much in 1 hour at 320
C as they do in 1 day at
100
C or in 1 week at 00
C. You know fruits and vegetables are living. They respire if the temperature is more,
their respiration rate increases. Thus, during handling it releases more heat and deteriorates the quality of the
produce. In addition to removal of field heat from commodities, pre-cooling also reduces bruise damage from
vibration during transit. The fresh produce can be cooled by:
• Natural cooling
• Forced air cooling
• Hydro cooling
• Natural Cooling-The natural cooling is the simplest method in which harvested produce is to be
kept in shade on a cemented floor or polyethylene sheet. It is the slowest method of cooling and
sometimes time taken to remove the field heat is so high that spoilage of produce starts during
cooling itself. Some people misunderstood this and kept the freshly harvested produce in cold room.
It may cause harm to the produce as warm fresh produce releases water which when condenses and
spoils the produce. Thus, such places should be equipped with good ventilation to remove the field
heat.
• Forced Air Cooling-Cold air is blown above the freshly harvested produce. It is many times faster
than the natural cooling. It suits most of the fruits, which cannot be dipped inside the water for
hydro cooling for i.e. strawberry, grapes etc. The main advantage of forced air cooling is that it not
only carried heat librated but also carries the moisture evaporated from the fruits. The only
disadvantage is if excess air is blown. Then loss of weight of fruit is high.
• Hydro Cooling-It is the most effective method in which freshly harvested produced are dipped in
cold water or cold water is sprayed over them. The advantage of this method is that it is fastest
method of cooling and washing the produce. However, it requires more energy because surface
water of the fruit is to be removed before packaging is done by forced aeration. The temperature of
water should not cause cold injury or the shower pressure shouldn’t damage the produce.
2. Washing, Cleaning and Trimming- Before fresh fruits and vegetables are marketed various amounts of
cleaning are necessary which typically involves the removal of soil, dust, adhering debris, insects and spray
residues. Chlorine in fresh water is often used as disinfectant to wash the commodity. Some fungicides like
Diphenylamine (0.1-0.25%) or ethoxyquin (0.2-0.5%) may be used as post-harvest dip to control an
important disorder of apple known as superficial scald.
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6. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Cooling method Commodity
Room cooling All fruits and vegetables.
Forced air cooling (pressure cooling)
Fruits and fruit type
vegetables, tubers and
cauliflower.
Hydro cooling
Stem, leafy vegetable,
some fruits and fruit type
vegetables.
Package icing
Roots, stem, some
flower type vegetables,
green onions and brussel
sprouts
Vaccum cooling
Some stem, leaf and
flower type vegetables.
Transit cooling All fruits and vegetables
Some roots, stems, leafy
vegetables
Mechanical refrigeration
Top icing and channel icing
Some crops contain non-edible parts/excess leaves with the produce. These unwanted portions
not only contain unnecessary bulk but also lead to microbial infection and water loss. Thus such produce
are to be trimmed before storage and handling.
2. Sorting, Grading and Sizing- Sorting is done by hand to remove the fruits, which are unsuitable to market
or store due to damage by insects, diseases or mechanical injuries. The remainder crop products are
separated into two or more grades on the basis of the surface colour, shape or visible defects. For example,
in an apple packing house in India 3 grades viz. extra fancy, fancy and standard may be packed for
marketing.
After sorting and grading, sizing is done either by hand or machine. Sizing on the basis of fruit
shape and size are most effective for spherical (oranges, tomato, certain apple cultivars) and elongated
(delicious apples, European pears or of non-uniform shaped commodities, respectively. Grading packing
line machines with facilities of washing, waxing and drying in addition to sizing are now days available in
the market.
3. Disinfection- Apart from these routine packing operations, such as cleaning, selection, grading and
packing of produce, some crops which are seasonal and subject to long-term storage, or are highly
perishable and transported over long distances to market (citrus, bananas, apples, etc.), require special
treatments in order to slow deterioration and minimize losses. Methods of disinfection are
• Spray or mist. For small-scale operations application is by hand-held knapsack sprayer or for large-
scale commercial operations by a mechanized spray rig in conjunction with a moving belt or roller
conveyor.
• Drenching. A simple mechanized recirculating system pumps fungicide in a cascade over produce
passing beneath it on a belt or roller conveyor
• Dipping. Where small quantities of produce are to be treated, the fungicide mixture is made up in a
small container and produce is dipped by hand. Excess fungicide is allowed to drain back into the
bath
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7. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
• Smoke or fumigant. Fungicide can be applied in the form of dust or vapor in closed containers, or in
sealed bulk stores. Such treatments are relatively rare. Bulk-store fumigation requires skilled
operation and is normally carried out by contractors..
2. Curing- Curing is an effective operation to reduce the water loss during storage from hardy vegetables viz.
onion, garlic, and other root vegetables. The curing methods employed for root crops are entirely different
than that from the bulbous crops (onion and garlic). The curing of root and tuber crops develops periderm
over cut, broken or skinned surfaces for wound restoration. It helps in the healing of harvest injuries,
reduces loss of water and prevents the infection by decay and attack by pathogens. Onion and garlic are
cured to dry the necks and outer scales. For the curing of onion and garlic, the bulbs are left in the field
after harvesting under shade for a few days until the green tops; outer skin and roots are fully dried.
3. Waxing- Waxing generally reduces the respiration and transpiration rates, but other chemicals such as
fungicides, growth regulators, preservative can also be incorporated specially for reducing microbial
spoilage, sprout inhibition etc. Commonly used waxes are paraffin wax, carnauba wax, bees wax, wood
resins, shellac, etc. The majority of quality contributing factors as affected by wax application includes
reduction in the physiological loss in weight (PLW), delay in respiration rate, reduction in post-harvest
spoilage and maintenance of improved quality of commodity intended for storage to increase the shelf life.
The principal disadvantage of wax coating is the development of off flavour if not applied properly.
Adverse flavour changes have been attributed to O2 and CO2 exchange, thus resulting in anaerobic
respiration and elevated ethanol and acetaldehyde contents.
4. Packaging- Proper or scientific packaging of fresh fruits and vegetables reduces the wastage of
commodities by protecting them from mechanical damage, pilferage, dirt, moisture loss and other
undesirable physiological changes and pathological deterioration during the course of storage,
transportation and subsequent marketing. Packaging cannot improve the quality but it certainly helps in
maintaining it as it protects the produce against the hazards of transportation. Mechanical damage to
packages occurs particularly during handling and transportation.. The package should have the following
features:
• It should have sufficient mechanical strength which can withstand dead load during transportation
(including impact and vibrations).
• It should be well aerated to remove respiration heat and humidity.
• It should be attractive and economical.
In general horticultural produce are handled through wooden cartons, corrugated fiberboard boxes and
plastic crates. To avoid damage produce by touching each other liners/fillers are used of corrugated
fiberboard or newspapers or grasses. Polyethylene lines are used to increase the humidity and decrease
the water loss from the fruits. The use of pallets and mechanical aids can reduce handling damage to
the package considerably.
5. Transportation- The refrigerated vans are the best method for transporting the produce from one place to
another. However, it is not common practice in our country. Therefore, open vans with system of air
movement to remove the respiratory heat should be practiced. In the van stacks should be arranged
uniformly with thick cushioning pads (straw) to absorb the shocks
Storage
Storage is one of the most important aspects of the post harvest handling of fruits and vegetables. The term
"storage", as now applied to fresh produce, is almost automatically assumed to mean the holding of fresh fruit and
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8. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
vegetables under controlled conditions. Although this includes the large-scale storage of some major crops, such as
potatoes, to meet a regular continuous demand and provide a degree of price stabilization
A substantial quantity of fruits and vegetables go waste in our country due to lack of proper storage. The primary
purpose of storage is to control the rate of transpiration, respiration, ripening and also any undesirable bio-
chemical changes or disease infection. Improper storage resulted in deterioration in fruits and vegetables in
following ways:
•Aging due to ripening, softening, and textural and colour changes
•Undesirable metabolic changes and respiratory heat production
•Moisture loss and the wilting
•Spoilage due to invasion by bacteria, fungi, and yeasts and insect pests
•Undesirable growth, such as sprouting of potato
The field heat of a freshly harvested crop should be removed as quickly as possible before shipping,
processing, or storage. In general fruits and vegetables are stored at low temperature and high humidity.
Appropriate storage conditions for storage of different horticultural produce for temporary/transit storage for 1-day
produce can be kept in the evaporating cool chamber where humidity is 90-95% and temperature is 10-15 oC lower
than the atmospheric temperature. Horticultural produce can be stored in modified atmosphere package (MAP) or
controlled atmosphere (CA). In this storage, the oxygen concentration is reduced (in general below 5%) and
carbon dioxide concentration is increased (3 to 7%). It helps in enhancing the shelf life and maintaining the quality
for longer period.
Factors affecting storage life
The natural limits to the post-harvest life of all types of fresh produce are severely affected by other biological and
environmental conditions:
• Temperature- An increase in temperature causes an increase in the rate of natural breakdown of all
produce as food reserves and water content become depleted. The cooling of produce will extend its life by
slowing the rate of breakdown. Many vegetables and fruits store best at temperatures just above freezing,
while others are injured by low temperatures. Crops such as cucumbers, pumpkin, and sweet potato are
highly sensitive to chilling injury. Similarly, the tropical and sub-tropical fruits like mango, banana,
papaya, pineapple etc. are also sensitive to chilling temperature. These crops may look sound when
removed from low temperature storage, but after a few days of warmer temperatures, chilling symptoms
become evident: pitting or other skin blemishes, internal discoloration, or failure to ripen.
• Water loss. High temperature and injuries to produce can greatly increase the loss of water from stored
produce beyond that unavoidably lost from natural causes. Maximum storage life can be achieved by
storing only undamaged produce at the lowest temperature tolerable by the crop.
• Relative Humidity:- Relative humidity is also important in the storage of fruits and vegetables. The
relative humidity of the storage unit directly influences water loss in produce. Water loss can severely
degrade quality-for instance, wilted greens may require excessive trimming, and grapes may drop loose
from clusters if their stems dry out. Water loss also leads to saleable weight loss and reduced profit. Most
fruit and vegetable crops retain better quality at high relative humidity (80 to 95%), but at this humidity,
disease growth is encouraged at higher temperature level.
• Decay in storage. Decay of fresh produce during storage is mostly caused by the infection of mechanical
injuries. Furthermore, many fruits and vegetables are attacked by decay organisms which penetrate through
natural openings or even through the intact skin. These infections may be established during the growth of
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9. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
the plant in the field but lie dormant until after harvest, often becoming visible only during storage or
ripening.
• Storage Sanitation:- Sanitation is of great concern to produce handlers, not only to protect produce
against post-harvest diseases, but also to protect consumers from food borne illnesses. E. coli, Salmonella,
Hepatitis, and Cyclospera are among the disease causing organisms.
• Ethylene Evolution:- Ethylene, a natural hormone produced by some fruits as they ripen. It promotes
additional ripening of produce when exposed to it. Damaged or diseased apples produce high levels of
ethylene and stimulate the other apples to age too quickly. As the fruits age or ripen, they become more
susceptible to diseases. Ethylene “producers” should not be stored with fruits, vegetables that are sensitive
to it. The result could be loss of quality, reduced shelf life, and specific symptoms of injury.
Bad effects of ethylene during storage include:
•loss of green colour in snap bean;
•increased toughness in turnips and asparagus spear;
•bitterness in carrots and parsnip;
•yellowing and abscission of leaves in cabbage, and cauliflower;
•accelerated softening of cucumbers;
•softening and development of off-flavour in watermelon;
•discoloration and off-flavour in sweet potato;
•sprouting of potato; and
•increased ripening and softening of mature green tomato.
Ethylene producers include apple, apricot, avocado, ripening banana, honeydew melons, ripe
kiwifruit, nectarines, papayas, peaches, pears, tomato
During Transportation
Most fresh produce is now moved in road vehicles, with lesser amounts by sea, air or inland
waterways. The vehicles in most common use are open pick-ups or bigger trucks, either open or enclosed.
A limited amount of high-valued produce is sometimes transported overland by air.
In all cases, the same conditions should be observed. Produce must be:
• kept as cool as possible;
• kept dry;
• moved to market as quickly as possible
In addition, the produce should be immobilized by proper cushioning in packs, packaging and stacking,
to avoid excessive movement or vibration. Vibration and impact during transportation may cause severe
bruising or other types of mechanical injury.
By Truck
The use of road vehicles is likely to increase, so users should give attention to the following:
• Refrigerated containers and trailers are more often used for long distance shipping, whether by sea, rail or
truck. Shipping by refrigerated trucks is not only convenient, but also effective in preserving the quality of
product. However, both the initial investment and the operating costs are very high. Another possibility is
insulated or properly ventilated trailer trucks.
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10. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
• Pre-cooled products can be transported through well-insulated non-refrigerated trucks for many hours
without any significant rise in product temperature.
• closed vehicles without refrigeration should not be used to carry fresh produce except on very short
journeys, such as local deliveries from farmers or wholesalers to nearby retailers;
• Open-sided or half-boarded trucks can be fitted with a roof on a frame. The open sides can be fitted with
canvas curtains which can be rolled up or moved aside in sections to allow loading or unloading at any
point around the vehicle. Such curtains can protect the produce from the elements but still allow for
ventilation. Where pilfering is a problem, the sides and rear of the truck must be enclosed in wire mesh;
• a second, white-painted roof can be fixed as a radiation shield 8 or 10 cm above the main roof; this will
reflect the sun's heat and help to keep produce cool;
• If the shipping distance is long, a ventilated truck is a better choice than an insulated truck without
ventilation and without refrigeration. Ventilation alone does not usually provide a uniform cool
temperature, but it may help dissipate excessive field heat and respiration heat, and thus avoid high
temperature injury.
Rail transport-In some countries a large amount of produce is carried by rail.
The advantages are:
• transport damage to produce while moving is slight as compared with that from haulage over rough roads;
• Costs are lower than transport by road.
Rail transport, however, requires extra handling since road transport is needed to and from the rail
journey; transport by road alone usually is a door-to-door service.
Water transport
Short-distance transport of fresh produce in small ships without refrigeration is common in countries of island
communities (e.g. the Philippines). Ships often accommodate passengers and general cargo, and no special
provision is made for fresh produce, which may be stowed in unventilated holds. Losses are high, owing to rough
handling by porters, inadequate packaging and overheating in unventilated holds or near engine rooms.
There is much room for improvement in this mode of transport. A model for organized and efficient sea transport
is the refrigerated shipment of commercial crops such as bananas, although a modest investment by the small-scale
shipper could greatly improve performance.
Air freight
As with shipping, the international trade in the air-freighting of high-value exotic crops is generally well
organized. In some countries where road links are poor (e.g. Papua New Guinea), produce is carried by air from
production areas to urban markets. Costs are high and losses often heavy because of:
• poor, non-standard packages;
• careless handling and exposure to the elements at airports;
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11. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
• consignments left behind in favour of passengers;
• flight delays owing to bad weather or breakdowns;
• intermittent refrigeration followed by exposure to high temperatures;
Pre-slaughter handling and transportation system – their effects on quality of meat
products, transportation and storage requirements, ante-mortem examination of animals
Preslaughter Care, Handling and Transport of Meat Animals.
It is not enough to produce healthy meat animals, it is equally important to ensure that these animals reach
the point of slaughter in sound condition. Preslaughter care and handling can markedly influence the quality and
quantity of meat. Ways of loading and unloading, means of transportation and average distance covered by the
animals from the point of production to the point of slaughter has definite bearing on the keeping quality of meat.
Excited, stressed, bruised and injured animals are not expected to yield wholesome meat.
The underlying principles for preslaughter, care, handling and transport of meat animals are:
1. To avoid unnecessary suffering of animals during transport.
2. To ensure minimum hygienic standards
3. To prevent spread of diseases.
TRANSPORT OF MEAT ANIMALS
The mode of transport should be decided on the basis of ground situation. Unless price differences are
significant, the animals should be taken to the nearby slaughter house or abattoir avoiding long journeys. It will
protect the animals from possible injury during loading and unloading as also adverse weather and inadequate
ventilation during transport. Various modes of transport may be
1. Driving on hoof
2. Transport by road truck
3. Transport by railroad
4. Transport by sea
5. Transport by air
1. Driving on Hoof
Animals reared within 6-10 k.m from the point of slaughter can be driven on foot. This distance can be covered in
4 to 5 hours. The time can be adjusted in early morning during summer and late morning during winter season.
This mode is especially suitable for animals accustomed to pasture grazing. It allows them to browse on
indigenous grass or shrubs and take water en route. So the animals suffer minimum weight loss or shrinkage due to
travel.
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12. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
2. Transport by Road Truck
Distance up to 500 km or 12-15 hours journey may be negotiated by road truck. Such vehicles should have non-
slip floor. It is also important to provide temporary or permanent protective overhead coverings, making provision
for adequate ventilation. Proper partitions should separate unequal sized animals or different species. The partition
height may vary from 25 to 120 on depending on the size of animals. Before the commencement of journey, the
animals should be offered adequate feed and water. If the journey is required to be continued after 12 hours, the
animals should be unloaded and offered enough feed and water. Transportation by road trucks allows convenience
of loading and unloading at the appropriate places.
3. Transport by Rail Road
For distances over 500 km, it is advisable to transport animals by railways. It is economic on maintenance and easy
to handle. Besides, there is a saving on extortions and other incidental expenses. Animals should be provided as lib
water and feed at least for an hour before the journey commences. It will be beneficial if water troughs are
provided within the roofed rail wagons. Railway wagons meant for this purpose should have a non-slip floor and a
free flow of air. Arrangement can be made to unload the animals after bout every 1000km and offer feed and water
before reloading. This made ensures comparatively less losses due to shrinkage and death. In fact, shrinkage losses
may come down to as low as 5 percent.
4. Transport by sea
Ships are used only for international transport.
5. Transport by Air.
It is very rare and used only for highly expensive animals.
Pre-loading precautions
There are a number of simple procedures that can be implemented prior to the loading of livestock, which will
considerably reduce the risk of injury and stress.
1. Pre-mixing of cattle or pigs leads to greater familiarity and these animals travel better than animals that are
strangers.
2. Fighting amongst pigs that are strangers is common, resulting in skin damage, wounds and stress. Mix pigs
from different pens together before loading, smearing pigs with litter or excreta from the same pen so that
they smell similar.
3. Most animals can be fed and watered before transporting.
4. Do not mix horned and hornless animals in the vehicles as these causes bruising and injury.
5. Different species should also not be mixed - sheep, goats and calves under 6 months can be mixed.
6. Bulls should not be carried together with other stock unless separated by a strong partition.
7. Animals that are diseased, injured, pregnant should not be transported to far because they cannot stand up
during transportation.
8. Vehicles should be fitted with a portable ramp to facilitate emergency offloading in case of prolonged
breakdowns.
EFFECT OF TRANSPORT ON MEAT ANIMALS
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13. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Poor transportation can have serious deleterious effects on the welfare of livestock and can lead to significant loss
of quality and production.
1. Stress - Leading to DFD beef and PSE pork. These conditions are sure
during transportation which lowers the meat quality. These conditions
may at times lead to shipping fever.
2. Bruising( ), torn skin and
broken bones
- Bruising is the escape of blood from damaged blood vessels into the
surrounding muscle tissue. Perhaps the most insidious and significant
production waste in the meat industry. Muscular bleeding may occur
especially in pigs
3. Trampling
- this occurs when animals go down due to slippery floors or
overcrowding
4. Heat stroke - pigs are susceptible to high environment temperatures and humidity;
5. Sun burn - exposure to sun affects pigs seriously;
6. Death it may occur during
long transportation:
- Sheep and pigs are easily affected if animals of unequal age and size
are loaded in road trucks without partitions due to suffocation. Sheep
and goats could also die in long distance transportation by ship due to
non-inflammatory diarrhea
7. Dehydration - animals subject to long distance travel without proper watering will
suffer weight loss and may die;
8. Fighting - this occurs mostly when a vehicle loaded with pig stops, or amongst
horned and polled cattle.
Effect on Meat Quality
Stress and fatigue before and during slaughter, the glycogen is used up, and the lactic acid level that
develops in the meat after slaughter is reduced. Thus, keeping quality of meat is reduced and it looks dark due to
higher water content. Pale Soft Exudative (PSE) and Dark Firm Dry (DFD) meats are two of the major quality
defects facing the meat industry. These defects reduce consumer acceptability, shelf life and yield of meat. The
energy required for muscle activity in the live animal is obtained from sugars (glycogen) in the muscle. In the
healthy and well-rested animal, the glycogen content of the muscle is high. After the animal has been slaughtered,
the glycogen in the muscle is converted into lactic acid, and the muscle and carcass becomes firm (rigor mortis).
This lactic acid is necessary to produce meat, which is tasteful and tender, of good keeping quality and
good colour. This acid gives meat an ideal pH level, measured after 24 hours after slaughter, of 6.2 or lower. The
24h (or ultimate) pH higher than 6.2 indicates that the animal was stressed, injured or diseased prior to slaughter.
Lactic acid in the muscle has the effect of retarding the growth of bacteria which are responsible for spoilage or
food poisoning.
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14. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Thus, meat from animals, which have suffered from stress or injuries during handling, transport and
slaughter, is likely to have a shorter shelf life due to spoilage. This is perhaps the biggest cause for meat wastage
during the production processes.
Pale Soft Exudative (PSE) meat
PSE in pigs is caused by severe, short-term stress just before slaughtering, for example during off-loading,
handling, stunning and holding in pens. Excitement, fright caused by manhandling, fighting in the pens and bad
stunning techniques may result in biochemical processes. Due to this a rapid breakdown of muscle glycogen takes
place and the meat becoming very pale with pronounced acidity (pH values of 5.4-5.6 immediately after slaughter)
and poor flavour. This type of meat is difficult to use or cannot be used and is wasted in extreme cases. Allowing
pigs to rest for one hour prior to slaughter and quiet handling will considerably reduce the risk of PSE.
Dark Firm and Dry (DFD) meat
This condition can be found in carcasses of cattle or sheep and sometimes pigs and turkeys soon after
slaughter. The carcass meat is darker and drier than normal and has a much firmer texture. The muscle glycogen
has been used up during the period of handling, transport and pre-slaughter and as a result, after slaughter, there is
little lactic acid production, which results in DFD meat. This meat is of inferior quality and has a shorter shelf life
due to the abnormally high pH-value of the meat (6.4-6.8). DFD meat means that the carcass was from an animal
that was stressed, injured or diseased before being slaughtered.
PRESLAUGHTER HANDLING OF ANIMALS
Handling of animals should conform to humane standards at every stage. It will safeguard the animal
welfare as well as meat quality. Rough handling of animals before slaughter can result in several physiological
stresses.
Arrangement of water is important in hot weather when lot of heat builds up in stationary trucks.
Preslaughter shearing and washing of sheep is quite stressful leads to bruises.
Not to mix strange animals shortly before slaughter in order to avoid fighting amongst them, especially
males.
Lairage serves as resting ground for the tired and stressed animals. Resting period depends on the length
and mode of journey, animal species, age, sex, condition.
Lairage should have adequate litter and drainage to avoid faecal soiling of skin.
The fed of animals should be with held for 12-18 hrs before slaughter whereas ample drinking water should
be made available during this period. It lowers the bacterial load in the instestine and facilities easy removable of
the hide or skin during dressing of carcases.
Stunning made more effective and brightness of the carcass is also improved.
Ante-mortem Examination of Meat Animals
Ante mortem Examination of meat animals awaiting slaughter is very necessary in order to produce to
whole some meat and thus safeguard the health of meat consumers. It should be conducted 12-24 hrs before
slaughter by qualified veterinarians. Hence, layout and construction of large should be such that it provides proper
light and provision of an isolation pen for diseased and injured animals. A number of para-veterinary staff should
also be at hand to help in the Examination. All animals meant for slaughter should be rested at least for 24 hours
and should not be fed for at least 12 hours before slaughter but they should be provided with plenty of water.
Objectives
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15. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
1. Detection of animals suffering from scheduled infectious diseases which are communicable to man.
2. To detect certain diseases which are toxic or contagious and whose identification is either difficult or impossible
during post mortem, e.g. tetanus, rabies etc.
3. To prevent food poisoning out breaks e.g. in salmonellosis carcass or organs show little noticeable change on
post mortem
4. To make postmortem examination more efficient, accurate and less laborious.
5. To protect the health of butchers and slaughter house personnel.
6. To prevent unnecessary contamination of building and equipment of the abattoir.
7. To implement disease control program with more precision by tracing back the source of disease.
Ante-mortem Examination procedure
It should be carried out in two stages
Stage I
General examination: Meat animals should be observed in the lairage pens during rest as well as in motion.
General behavior, fatigue, excitement, gait, posture, evidence of cruelty, level of nutrition, symptoms of diseases,
or any other abnormalities should be closely observed.
Stage II
Detailed examination: Suspected or diseased animals should be segregated for detailed examination. Their
temperature, pulse rate and respiration rate should be recorded. Animals showing elevated temperature and
systematic disturbance should be detailed for further inspection and treatment in the isolation pen
. Animal Temperature Pulse min Respiration min Gestation period
Sheep and Goat 39.5c 75 12.20 147 days
Pigs 39c 75 10.16 112 days
Cattle and Buffaloes 39c 50 12.16 280 days
Principles of judgment in Antemortem Examination
1. Fit for slaughter- Animals which are normal and free from any symptoms of disease should be sent for
sacrifice
2. Unfit for slaughter- highly emaciated, skin bound animals and those affected with tetanus or communicable
diseases like rabies etc. or diseases which can not be treated should be declared unfit for slaughter.
3. Suspects- All suspected animals need further attention. Some animals with localized condition and recovered
cases should be passed for slaughter as suspect with instructions for careful postmortem examination.
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16. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
i. Detained animals some animals need to be detained for specified period of time for treatment of disease
or excretion of known toxic residence.
ii. Emergency slaughter It is recommended in cases where the animal is in acute pain or is suffering from a
condition where any delay in slaughter would be contrary to the welfare of animal. It is done under strict
supervision so that there is no hazard to the consumer health.
ANTEMORTEM INSPECTION
Some of the abnormalities which are checked on antemortem examination include:
1. Abnormalities in respiration
2. Abnormalities in behaviour
3. Abnormalities in gait
4. Abnormalities in posture
5. Abnormalities in structure and conformation
6. Abnormal discharges or protrusions from body openings
7. Abnormal colour
8. Abnormal odour
1 Abnormalities in respiration commonly refer to frequency of respiration. If the breathing pattern is
different from normal the animal should be segregated as a suspect.
2 Abnormalities in behaviour are manifested by one or more of the following signs:
The animal may be:
a. walking in circles or show an abnormal gait or posture
b. pushing its head against a wall
c. charging at various objects and acting aggressively
d. showing a dull and anxious expression in the eyes
3 An abnormal gait (chaal) in an animal is associated with pain in the legs, chest or abdomen or is an
indication of nervous disease.
4 Abnormal posture in an animal is observed as tucked up abdomen or the animal may stand with an
extended head and stretched out feet. The animal may also be laying and have its head turned along its side. When
it is unable to rise, it is often called a “downer”. Downer animals should be handled with caution in order to
prevent further suffering.
5 Abnormalities in structure (conformation) are manifested by:
a. swellings (abscesses) seen commonly in pigs
b. enlarged joints
c. umbilical swelling (Naal ki sujan) (hernia)
d. enlarged sensitive udder indicative of mastitis
e. enlarged jaw
6 Abnormal colour such as black areas on horses and swine, red areas on light coloured skin (inflammation),
dark blue areas on the skin or udder (gangrene).
7 An abnormal odour is difficult to detect on routine antemortem examination. The odour of an abscess, a
medicinal odour, stinkweed odour or an acetone odour of ketosis may be observed.
Examination of a carcass should be carried out as soon as possible after the completion of dressing in order to
detect any abnormalities so that
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17. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Collection, pre-cooling, handling and transportation systems – their effects on quality of
milk
Milk: - Milk is defined as the secretion of mammary glands intended for the immediate nutrition of newly born
offspring.
For any milk industry, raw fluid milk is the basic raw material. Milk is often made to undergo some
processes which are applied to it before it comes to the market for selling. Chilling, packaging and transportation
of milk is a part of dairy technology that deals with milk processing on an industrial scale.
Introduction
Raw field milk is the basic raw material for the dairy processing industry. A dairy is a place for handling
milk and milk products. India's dairy processing industry has developed rapidly since after 1950.
The task of procuring milk and getting it to our dairy processing plants is a complex problem involving
ownership, pricing, collecting, grading, measuring, weighing, testing, bulking, transporting and chilling, packaging
and heating. Chilling, packaging and transportation of milk is a part of dairy technology which deals with the
processing of milk on an industrial scale. Milk must be cooled as soon as possible after it is produced. A
temperature of 4°C or less is recommended. It is very necessary, because as long as this temperature is maintained,
bacterial action in the milk is retarded if not prevented.
Collection of milk
There are three methods of collection of milk:-
1. By co-operative organization
2. By contractors
3. By individual producer or suppliers
The main objectives of collections of milk are:-
1. To arrange adequate quantity of milk for city. Milk plant to meet the requirement of installed capacity.
2. To provide readily available market for milk product by the farmer and to ensure for best price for them.
3. To satisfy the milk demand of the increasing population.
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18. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Location of milk collection cum chilling center:-
1. Where adequate milk production.
2. Adequate water supply.
3. Good road and rail link.
4. Good electric supply.
5. Good sewage disposal facilities.
Operational procedure in milk collection cum chilling center:-
On arrival of milk first grading is done on the basis of sensory tests are:
1. Appearance
2. Smell
3. Taste
1. Appearance: - it means white or off white on colour. If there s any off colour in the milk them milk can
be rejected.
2. Smell: - it means if foul smell then rejected.
3. Taste: - it means if sour taste rejected.
After that sample is collected for chemical analysis and their platform test i.e. COB, fat, SNF, pH, acidity, sugar,
alcohol, preservative, neutralizers, dye reduction tests.
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19. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Cooling
Methods of cooling/pre-cooling
There are several methods of chilling which are mentioned here:
1. Can immersion,
2. Can cooling,
3. Surface cooler,
4. Tubular cooler,
5. Plate chiller,
6. Bulk milk cooler.
1. Can immersion
In this method milk cans are immersed in a water tank containing ice water. The milk inside the can is
stirred with the help of plunger for uniform cooling. This system is less expensive, simple and suited for a
small scale operation. Since the cans are not insulated, the transport to the factory must be efficient enough to
enable milk reach the factory in acceptable condition.
Disadvantages:
• Cooling process is not very efficient,
• encourages contamination of milk,
• requires more time and labour, and
• Cannot be adopted for large operations.
Chilled water can be sprayed on milk cans by using an electrical pump or an agitator which can be mounted
on the cabinet to fasten cooling.
2. Surface cooling
Several hollow pipes are horizontally welded and they are joined at both the ends so that the water can flow
through the pipes without interruption. These pipes are mounted on a strong iron frame. On top a milk supply tank
is provided which delivers milk at the lower end of the pipes milk is collected in the milk cans.
In this method of cooling ice-water or chilled water is used for cooling the milk. Chilled water is pumped
through the pipes and milk flows over the pipes: in the form of thin film. As the milk travels downward; its
temperature is being reduced progressively. If the flow of milk is uniform as chilled water is properly regulated,
then the temperature of chilled milk is nearly the same as that of chilled water.
Advantages
1. More efficient cooling,
2. Cost of operation is low,
3. Less labour is involved,
4. More milk can be handled,
5. Initial cost is low as compared to plate chiller and bulk milk cooler,
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20. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
6. Less chances for contamination.
Disadvantages
1. Regular supply of chilled water is required
2. Milk is exposed to atmosphere during cooling process
3. Maintenance of pump and refrigeration plant is involved
4. Process can not be adopted for a large operation.
4. Tubular Cooling
In this method of cooling milk is passed through a hollow pipe which is placed inside another pipe having
larger diameter. The length and diameter of both the tubes are determined according to capacity of the plant. In one
of the tubes, milk flows, while in the other chilled water flows. The flow of milk and chilled water is in opposite
direction. The arrangement is called counter-current method. The cooling efficiency is more when compared to co-
current method where the cooling medium and the liquid to be cooled, flow in the same direction.
5. Plate chiller
This is the most widely used equipment for chilling of milk by the commercial dairy plants. Several
stainless steel plates are mounted on a solid stainless steel frame in which the flow of milk and chilled water is so
arranged that in the alternate plates chilled water flows and yet it does not mix with water. The flow is always in
opposite direction (counter- current). The chilled water circulates through the plate chiller. Milk is pumped directly
from the dump tank which passes through the plate chiller and goes to the raw milk storage tank. The number of
plates and size of plates in the chiller depend upon the capacity of the plant.
This method of chilling is more efficient, more hygienic, involves less manual labour and low cost when
plant is operated to its capacity). There are several disadvantages of this system of chilling.
a. Cannot be adopted without electricity.
b. Requires technically trained personnel.
c. Regular supply of chilled water is required.
d. Initial cost is high.
e. Suited only for large operation.
6. Bulk Milk coolers/In-tank cooler
Bulk milk cooler consists of a double jacketed vat fitted with a mechanical agitator. It also has provision
for circulation of chilled water which comes from the chilled water tank. As the name itself suggests it is meant for
bulk quantities. Normally milk is chilled and subsequently stored at low temperature until transported to
processing units for further processing. The agitator is used for stirring the milk which helps in uniform cooling.
Bulk milk coolers are generally installed in chilling centre.
Advantages
a. They are used for cooling as well as storage of milk.
b. Contamination of milk through external agencies is avoided.
c. Less labour is involved.
d. Operational costs are low
Disadvantages
a. Requires electricity,
b. Initial cost is more,
c. Suited only for large scale operation.
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21. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Transportation
In India bulk of the milk is produced in the rural areas and it has to be transported as raw milk from the
place of its production to the urban dairies for processing and ultimate consumption. Due to adverse climatic
condition and excessive cost of refrigeration, transportation of milk must be regularly done twice a day (morning
and evening). The transport system should therefore, be most efficient and economical. There are various modes of
transportation based on various considerations.
Mode of transport
Sr. No. Mode of transportation Quantity(Liter) Distance(km)
1 Head Load 15-20 3-8
2 Shoulder sling up to 40 3-6
3 On animal up to 80 6-10
4 Bullock carte 300-400 10-12
5 Bicycle 40 or more 5
6 Cycle rickshaw 150-200 10 or more
7 Auto rickshaw 250-500 15
8 Truck ½ tones to 3 tones 15
9 Rail wagon 11 tones 80
10 Tanker (Rail or Road) 5 tones 80
1. Head Load
Generally producers carry milk on their head to the collection or chilling centre. This is commonly
practiced in hilly areas where the volume of milk to be transported is less and the other means of transportation are
not convenient. The practice of head load transportation of milk is restricted to 3 to 5 litres of milk for a short
distance.
2. Shoulder sling
This method of transportation is again restricted to hilly areas where other means of transportation are not
easily available. The quantity of milk may vary from 10 to 20 litres.
3. Bullock cart
The size and design of cart or tonga differs from place to place simultaneously, the volume of milk
transported and distance to be covered. Both these means of transportation are employed in areas where the area is
plain and some kind of road exists.
4. Bicycles
In the recent years use of bicycle in the rural areas has increased tremendously. Door to door delivery of
milk by the milk man by bicycle up to 40 litre of milk for a distance of about 10 to 15 km on a bicycle is a
common mode of transport in this country. It is faster, more convenient and aso a cheaper mode of transportation
of milk.
5. Cycle Rickshaw or auto-rickshaw
They have more capacity than bicycle. Cycle rickshaw can carry more load than bicycle and auto rickshaw
can carry more than cycle rickshaw. Auto-rickshaw can carry 250 to 500 litres milk for a distance or 15 to 20 km.
These modes of transportation involve less initial expenditure and their maintenance is also comparatively cheaper.
6. Boat
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22. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
The method of transportation of milk is limited. But in some places boat may be the convenient mode of
transport of milk through boat. Normally small boats carry about 200 litres of milk for short distance.
7. Motor truck
As the automobile industry in India has shown remarkable progress, use of motor trucks as a means of
transporting milk in truck has become very popular. Almost all the dairies make use of motor trucks for the
transportation of milk particularly when the milk is to be transported in cans. They carry approximately 0.5 to 3.5
tonne load for more than 100 kg. Due to improvement in road facilities and construction of all reason roads, motor
trucks have been found to be most effective means of transportation.
8. Railway wagon
Railways have been most dependable means of transportation. Railway wagons are economical only when
a high volume of milk is to be transported for comparatively longer distances. Railway wagons can carry
approximately 10 to 12 tonnes of load for more than 100 kin. They are considered economical and feasible where
handling is large.
9. Tankers (Rail and road)
Insulated stainless steel tanks are mounted either on the road or rail truck. These tankers are economical
for bulk handling and for long distance transportation. A good number of rail as well as road tankers are in use.
There tankers are outcome of technological advancement in the field of design and development of equipment
within the country.
HYGIENIC MILK HANDLING AT DAIRY FACTORIES
i. Floors and Walls of dairy buildings should be smooth and washable to about 2 meters from floor.
ii. Doors should be self shutting while windows should be rendered insect proof by mosquito netting to keep
flies out.
iii. Rooms should be kept clean and in good repair.
iv. All product-contact surfaces should be kept cleaned immediately before use or as often as necessary.
v. Equipment and utensils should be disinfected immediately before use, and whenever there has been
possibility of accidental contamination.
vi. Equipment repairs and maintenance should preferably be carried out after processing.
vii. Equipment used for handling liquid milk products should preferably be cleaned and disinfected after each
period of use and at least daily.
Disinfection of dairy equipment may be carried out by means of:
• Steam - Steaming should be done for 10- l5 minutes after the condensate has attained 85° C.
• Hot water - Hot water at8O° C (use soft water only to prevent deposition of salts) for at least 20 minutes in
circulation cleaning for 15 minutes at 85° C
• Detergents/disinfectants - used as part of the cleaning process at temperatures between 45-60° C in manual
cleaning and for cold milk lines, storage tanks and tankers.
Effect of collection, handling, cooling and transportation on milk quality
Milk inside the udder is almost sterile and as soon as it leaves the udder, it is exposed to atmospheric
conditions. The micro- organisms gain entry into the milk. The number and type of micro-organisms would
depend upon the conditions and the sources of contamination. As soon as micro-organisms get into the milk, they
start growing rapidly because milk contains all the nutrients required for their growth. If the growth of
microorganisms is not checked then several biochemical changes will take place in milk.
The common microorganism can grow easily between 20-40°C therefore the raw milk should be cooled to
5°C or below and hold at this temperature till processed. The numbers of microbes in the sample of milk is double
22

23. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
in about half an hour and at 15.5o
C about 4 hours and at 10o
C about 8 hours and at 4.4o
C about 39 hour were
needed to double of the original number.
The growth of micro-organisms can also be stopped by adding certain chemicals but the addition of such
substances is illegal and unethical because they are injurious to human health. The most effective means of
controlling the growth of micro-organisms without effecting the physico-chemical properties and nutritive value of
milk is to chill it. Lower temperature inhibits the growth of most of the micro organisms.
During Storage milk should be protected from exposure to light because when milk is exposed to strong
light or to sunlight for a few minutes, an off-flavour' suntaste' is developed due to oxidation of an amino acid in
milk protein.
Milk has natural Acidity (0.14 to 0.16%) or apparent acidity that comes from the component of the milk
such as albumin, casein, phosphate citrate and carbon dioxide. During handling and storage various sources
contribute to the micro flora and acidity development in milk are milk containers, udder of the animal, dust and
dirt particles, fodder (), leaves, air, the milker and the animal itself. Developed acidity is also come from
fermentation of lactose to lactic acid by streptococcus lactis by lactic acid fermentation.
The fat and protein in milk may undergo chemical changes during processing and storage. These changes
are normally of two kinds: Oxidation and hydrolysis, the resulting reaction products can cause off-flavours
principally in milk and butter.
Candling and grading, packaging, handling, pre-treatment, transportation and storage
EGG
Structure, Composition and Nutritive Value of Eggs is necessary to effectively preserve its quality during storage
and marketing. There are four main components of hen’s egg:
a. Shell
b. Shell membranes
c. Albumen or white
d. Yolk
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24. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
i. Shell The outer protective covering of an egg is shell which comprises around 1% of its total weight. It is mainly
composed of calcium carbonate. The shell contains numerous minute pores on the entire surface, which are
partially sealed by cuticle. These pores allow loss of carbon dioxide and moisture from the eggs.
ii. Shell membranes. The shell is attached to the shell membranes. The outer thick and inner thin membranes are
usually inseparable except at the broad end of the egg forming an air cell. The shell membranes are a part of in-
built defense mechanism in the egg because of their role as an effective barrier against bacterial invasion. The air
cell continues to increase in size during storage due to loss of moisture and shrinkage of egg contents.
iii. Albumen The white or albumen portion of egg constitutes about 58% of the total weight of an egg. It occurs in
occurs in four layers as follows:
a. Outer thin layer
b. Outer thick layer
c. Inner thin layer
d. Inner thick white or chalaziferous layer. .
iv. Yolk. Constitutes nearly 31% of the total egg weight. It consists of the following four structures from outside:
Chemical Composition of egg
As mentioned earlier, an egg consists of 11% shell, 58% albumen and 31% yolk. The cuticle of egg shell is
composed of a foaming layer of proteinaceous matter especially keratin. It covers the calcified portion of the shell
which is made up of calcium carbonate (94%) with minor quantities of calcium phosphate (1%), magnesium
carbonate (%) and proteinaceous material especially keratin. The true cell membrane consists of protein fibers. The
inner membrane is comparatively thick.
Chemical
composition of egg
Component
Total (%) Water (%) Protein (%) Fat (%) Ash (%)
Whole egg
Albumen
Yolk
Shell
00
58
31
11
65.5
88.0
48.0
Calcium
Carbonate
(%)
94.0
11.8
11.0
17.5
Calcium
Phosphate
(%)
1.0
11.0
0.2
32.5
Magnesium
Phosphate
(%)
1.0
11.7
0.8
2.0
Organic
Matter
(%)
4.0
Candling
"Candling" is the examination of the contents of the eggs using a shielded light in a
darkened area.
Candling is the process of holding a strong light above or below the egg to observe the embryo. A candling
lamp consists of a strong electric bulb covered by a plastic or aluminum container that has an aperture (hole). The
egg is placed against this aperture (hole) and illuminated by the light. Candling detects bloody whites, blood spots,
or meat spots, and enables observation of germ development. During incubation the air sac size should increase as
moisture evaporates from the egg. If your humidity levels are about right, the air sac should increase at different
days of incubation. Candling is done in a darkened room or in an area shielded by curtains.
Candling is a way of checking whether
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25. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
• Infertile eggs: These are easy to detect, as the egg is clear. Discard
• Early deaths: The embryo has developed for several days and then died. ). A small dark area and
disrupted blood vessels seen. Embryo with red blood “ring”. Discard.
• Late Deaths: These are often difficult to tell. Look for the absence of movement and the breakdown of
the blood vessels. Discard
• Viable Embryos: These move in response to the light and have well defined blood vessels. Mark the air
sac and the inoculation site and then return the eggs to the incubator ready for inoculation.
When to Candle
White eggs should be tested for fertility on the third day. Brown shelled eggs on the fifth or sixth day because it is
difficult to see the embryo clearly before this time.
Day 8 onwards is usually when the embryo is more easily identified.
1. Day 3 of incubation (usually pale shelled eggs).
2. Day 5/6 of incubation (usually dark shelled eggs).
3. Between day 8 - 12 of incubation (embryo more easily identified).
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26. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
How to Candle?
In a darkened room, carefully hold the egg up to the light to observe the
contents of the egg. The light penetrates the egg and makes it possible to
observe the inside of the egg. The embryo is located at the large end of
the egg. In candling, the egg is held in a slanting position with the large
end against the hole in the Candler.
The egg must be hold between the thumb and tips of the first two
fingers, is turned quickly to the right or left. This moves the contents of
the egg and throws the yolk nearer the shell. Mark with any marker for air
cell or any other spot Any eggs you are not sure of, pencil a question
mark onto. Have another look at them later. Dark or brown shelled eggs
are more difficult to candle than white or pale shelled eggs.
This egg candle can be made from a tin can that's about 5 inches in diameter and 7 to 9 inches long.
A shortening can with an easily removable lid works well.
Grading
It is the form of quality used to divide a variable commodity or product into a number of classes according to
physical and quality characteristics of economical importance. Egg grading involves inspection of cell for
soundness, cleanliness, appearance, strength and shape. The interior quality of egg is determined by candling and
they divided into different classes on the basis of quality, shape and weight.
In India eggs are divided into four grades, according to their weight i.e.
1. Extra large 60 grams
2. large 53-54 grams
3. medium 43-52 grams
4. small 38-42 grams
U.S Grading of eggs
AA grade:
a) Clean, unbroken and practically normal shell
b) Air cell must not exceed 1/8th inch in depth, unlimited movement and may be free and bubbly
c) White must be clear and firm
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27. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
d) The yolk must be practically free from defects.
A grade:
a) Clean, unbroken and normal shell
b) Air cell must not exceed 3/16th inch in depth, unlimited movement, free and bubbly.
c) Clear and reasonably firm white
d) Yellow also should be fairly well defined without defects
B grade:
a) Unbroken, may be abnormal and can have slightly stained areas.
b) Stained areas are permitted if they do not cover more than 1/32th of the shell surface if localized or 1/16th of the
shell surface if scattered.
c) Egg surface should not be dirty.
d) White may be weak and watery
e) Air cell may be over 3/16th inch in depth, show unlimited movement, free and bubbly
f) Yolk outline is slightly visible
g) Yolk may appear dark, enlarged and flattened and may show clearly visible germ development but no blood
h) Small blood spots and meat spots may be seen.
Packing
Packing of egg is normally carried out of to protect them from microorganism such as bacteria, loss of moisture,
tainting, temperature that cause
deterioration and possible crushing.
While being handled, stored or
transported. There are different types of
packing material use.
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28. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Type I: - Packing eggs with clean and odorless rice husk, wheat chaff of chopped straw in firm walled.
Type II: - A very common form of packing is the filler tray. The fillers are then placed in boxes. Fillers trays are
made of wooden pulp molded to accommodate the eggs. Fillers can also be made of plastic. The advantages of
using fillers are that they can be reused and are washable. The filler can be covered with plastic covering and the
used as packing for final sale to the buyer.
Type III: - Eggs can be also being packed in
packing that is smaller and specific for retail sale.
Each packing can hold from 2 to 12 eggs. These
cases can be made of paper board or molded
wooden pulp or can be made of plastic. The
packing can be made of polystyrene. The main
advantages of using polystyrene are superior
cushioning and protection against odors and
moisture.
Handling
A freshly laid egg can be assumed to have a highest quality. Since egg is full of essential nutrients,
deteriorative changes soon start taking place which may pose a danger to the excellent sensory attributes of this
nourishing and satisfying food item. Cleanliness and soundness of shell is the first step to assure the quality of egg
to the consumers. The shell quality deficiencies mostly relate to the production practices adopted at the farm.
Proper handling of eggs can delay the decline in the quality. Following precautions should be taken during
handling of eggs:
I. Eggs should be collected 3 to 4 times per day. This will result in less dirty eggs and fewer breakages.
II. Many a time we use metal basket for handling eggs at the farm which increase the chances of handling
damage i.e. beneficial to collect eggs in plastic or wooden pulp molded trays
III. After collection, eggs should be shifted to holding room maintained at a temperature of about 15 0
C and 70
to 80% RH at least for 12 hours.
IV. Eggs should be properly packed in filler flats with broad end up. Bulk packing should be done in fibre
board cartons.
V. Eggs should be rapidly moved through the marketing channel so as to reduce the period between
production and consumption.
Effect of mishandling which lower the quality of egg as it ages:
i. As the surface of egg dries, the keratin cuticle shrinks and size of shell pores increases rendering it easier for
gases and microorganisms to pass in and out of the shell.
ii. As the warm egg contents also contract, resulting in the formation of air cell.
iii. The breakdown of carbonic acid causing loss of carbon dioxide from the albumen is rapid during the first few
hours after an egg is laid. The alkaline pH acts on the mucin fibres to disturb the thick gel of albumen making it
thin or watery.
iv. As the egg ages, water migrates from the albumen to the yolk which may overstretch, weaken or even rupture
the vitelline membrane.
Storage of Eggs
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29. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Following methods are employed to maintain the quality of shell eggs during storage
1. Egg Cleaning
Earlier, it was a general practice to dry-clean dirty egg shells by abrasive mounting on a mechanical wheel.
This practice has now become obsolete because it weakens the shell. These days washing in warm water
containing a detergent sanitizer is an effective way of cleaning the eggs with dirty shells.
A temperature difference of 10-150
C between eggs and wash water is ideal; otherwise there may be problem of
crack shells. Besides, eggs should not be immersed in warm water for more than 3-4 minutes. After washing, the
eggs should be dried promptly. Wash water should be changed after washing every five to six baskets of eggs. It
should be emphasized that only dirty eggs are subjected to washing. It not only reduces the microbial load on the
egg shell surface but also improves the appearance and consumer appeal.
2. Oil Treatment
Oil coating spay of eggs has become very popular for short term storage of this commodity. Coating oil forms
a thin film on the surface of the shell sealing the pores. It should be done as early as possible, preferably within
first few hours after lying of eggs because loss of CO2 is more during this period and evaporation of moisture is
also more during the first few days.
Egg coating is done by dipping the eggs in the groundnut oil whereas for oil spray, the eggs are arranged in
the filler flats with their broad end up. If the eggs need washing, oil coating should be done after washing. It is
important to drain out excess oil before packaging. The temperature of oil should be in range of 15 to 300
C for
ideal results. Oil treatment safeguards the quality of albumen for at least 7 days because it effectively seals the
shell pores.
3. Cold Storage
This method of preservation is suitable for long tern storage of clean eggs in the main laying season and
abundant availability. The temperature of cold store is maintained at 00
C (320
F) and relative humidity between 80
to 85 per cent. An anteroom with intermediate temperature is generally provided to check condensation of water
vapour on the eggs during removal. Uses of new egg packing trays are advised for cold storage. Like all other
animal products, eggs also pick up strong odour, so the same cold store cannot be used for storing onion, garlic or
any other commodity with strong odour.
The quality of shell eggs can be maintained for about 6 months in a cold storage. Oil coating of eggs prior to
cold storage can further enhance their keeping quality. Such eggs could keep well at 140
C and 90% RH for a
period of 8 months.
4. Thermostabilization
This preservation method involves stabilization of albumen quality by holding the eggs in an oil bath
maintained at 550
C for 15 minutes or 580
C for 10 minutes. This process brings about coagulation of thin albumen
just below the shell membranes, thereby blocking the passage of air and moisture. In addition, oil coating of shell
pores also takes place. Thus keeping quality of eggs is maintained for sometimes and thinning of egg white is
retarded. Alternatively, eggs are immersed in hot water at 710
C for 2 to 3 seconds. In this flash heat treatment,
bacteria present on the surface of the shell are destroyed and a thin film of albumen just below the shell membrane
is coagulated sealing the egg shell from inside.
5. Immersion in Liquids
Under rural conditions, lime-water or water –glass immersion are most useful. In lime-water treatment, a litre of
boiling water is added to 1 kg of quick lime and allowed to cool. Now 5 litres of water and 250g of table salt are
added to it. The solution is strained through a fine cloth when the mixture settles down. Eggs are dipped in the
clear fluid overnight and then dried at room temperature.
In this process, an additional thin film of calcium carbonate is deposited on the egg shell and seals the
pores. Such eggs can be stored for a month at ambient temperature. In water-glass treatment, one part of sodium
silicate is mixed in 10 parts of water and eggs are dipped overnight. In this process, a thin precipitate of silica is
deposited on the egg shell and partially seals the pores.
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30. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
It is clear from the above discussion that eggs should be collected frequently, held initially at low temperature and
then a suitable preservation method be employed to maintain its keeping quality for anticipated consumer
acceptance.
Transportation of Eggs
Transport of eggs packages are usually by two means, rail and road. The airways and waterways are hardly ever
employed for this purpose, except for export. It has been observed that is has advantageous/beneficial to transport
eggs by rail when the distances involved are more than 100 km. while road transport is more convenient for
distances less than 100 km. following points should be adopted to maintain egg quality during the transportation:-
1. The first and foremost point is that the containers and packing material should be such that the eggs are
well protected against possible mechanical damages.
2. Handler should handle the egg packages with extra care i.e. by the use of lifts, ramps or other suitable
means of loading.
3. When the transport duration is over2-3 days, the loading temp should be maintained around 60
C and -1 to
30
C during transpiration. When the transport duration is increased to around 6 days temperature during
loading should be maintained at 30
C and during transportation between -1 to 1 0
C
4. Excessive shaking and vibration of egg containers during transportation should be avoided
5. For long distances transportation insulated refrigerated vans should be projected. In case where vans are
not available transportation of egg cases should be done preferably during night and cooler part of the day
Cold Storage- Introduction to cold storage facilities & requirements for storage of different fruits and
vegetables.
India is the largest producer of fruits and vegetables in the world scenario but the availability of fruits and vegetables
per capita is significantly low because of Post Harvest loses which account for about 25% to 30% of production.
Further, the quality of sizeable quantity of produces also deteriorates the moment it reaches the consumer. This happens
because of perishable nature of the products. If consumption is not getting stabilized, the farmers switch over to other
crops instead of going for one crop in the subsequent year, and cycle continues.
Introduction of Cold storage / Cold room facility will help them in removing the risk of distress sale and
simultaneously will ensure better returns.
Refrigeration (cold store) – The ideal environmental condition for storage of fresh fruits and vegetables is the
lowest temperature which does not cause chilling injury to the product. Hence, temperature control in cold storage is
very important. In mechanical refrigeration, the refrigerated Gas (e.g. Ammonia, Freon etc.) takes out the heat from the
chamber/store as it expands. The expanded gas is then compressed and the heat removed from the compressed gas by
means of running water or circulation air over the tubes containing the hot gas. The gas is liquefied and the cycle is
repeated. With such system accurate temperature control is maintained.
Storage of foods and Storage Conditions
Deterioration of fruits and vegetables during storage depends largely on temperature. One way to slow
down this change and so increase the length of time fruits and vegetables can be stored, is by lowering the
temperature to an appropriate level. Foods and many other commodities can be preserved by storage at low
temperature, which retards the activities of micro organisms. Micro organisms are the spoilage agents and consist
of bacteria, yeasts and molds. Low temperature does not destroy those spoilage agents as does high temperature,
but greatly reduces their activities, providing a practical way of preserving perishable foods in their natural state
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31. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
which otherwise is not possible through heating. The low temperature necessary for preservation depends on the
storage time required often referred to as short or long term shortage and the type of product.
In general, there are three groups of products:
1. Foods that are alive at the time of storage, distribution and sale e.g. fruits and vegetables,
2. Foods that are no longer alive and have been processed in some form e.g. meat and fish products, and
3. Commodities that benefit from storage at controlled temperature e.g. beer, tobacco, khandsari, etc.
Long term storage of meat and fish product can only be achieved by freezing and then by storing it at temperature
below -15o
C. Only certain fruits and vegetables can benefit from freezing. Products such as apples, tomatoes,
oranges, etc. cannot be frozen and close control of temperature is necessary for long term storage.
Dairy products are produced from animal fats and therefore non living foodstuffs. They suffer from the oxidation
and breakdown of their fats, causing rancidity. Packaging to exclude air and hence oxygen can extend storage life
of such foodstuffs.
Heat load factors normally considered in a cold storage design are:
1. Wall, floor and ceiling heat gains due to conduction
2. Wall and ceiling heat gains from solar radiation
3. Load due to ingression of air by frequent door openings and during fresh air charge.
4. Product load from incoming goods
5. Heat of respiration from stored product
6. Heat from workers working in the room
7. Cooler fan load
8. Light load
9. Aging of equipment
10. Miscellaneous loads, if any
Desired Storage Environment of Fruits and Vegetables in the cold storage
Commodity Temperature (oC)
Relative
Humidity (%)
Apple -1 - 3 90 - 98
Apricots -0.5 - 0 90 - 95
Avocado 7 - 13 85 - 90
Asparagus 0 - 2 95 - 97
Beans, green 4 - 7 90 - 95
Beet root 0 - 2 95 - 97
Broccoli 0 - 2 90 - 95
Black berry -0.5 - 0 95 - 97
Cabbage 0 - 2 90 - 95
Carrots 0 - 2 90 - 95
Cauliflower 0 - 2 90 - 95
Cherries 0.5 - 0 90 - 95
Cucumber 7 - 10 90 - 95
Brinjal 0 - 2 90 - 95
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32. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Grapes -1 - 1 85 - 90
Lemons 4 - 15 86 - 88
Lettuce 0 - 1 95 - 98
Lime 3 - 10 85 - 90
Mango 11 - 18 85 - 90
Melon water 2 - 4 85 - 90
Orange 0 - 10 85 - 90
Peach -1 - 1 88 - 92
Potato 1.5 - 4 90 - 94
Harvesting-It is essential that fruits and vegetables are not damaged during harvest and that they are kept
clean. Damaged and bruised produce have much shorter storage lives and very poor appearance after
storage. Dirty produce can introduce pests and moulds into the store.
The produce should be harvested carefully using a sharp stainless steel knife. The fruits and
vegetables should not be placed on the ground where they could pick up dirt. Either a clean harvesting
basket or clean mats should be used.
It is essential that the fruits and vegetables are harvested at the correct harvesting time.
Handling
It is important that the produce does not get dirty or damaged during handling. Careful handling should be the rule.
The best option is for the produce to be prepared for storage in the field and placed carefully in the storage
containers used in the cold store. This considerably reduces the amount of handling and will keep damage to a
minimum. It is essential that the produce is handled and placed in the store as quickly as possible as delays
between harvesting and cooling can substantially reduce storage life.
Preparation
If the produce is dirty it should be cleaned before storage. The water used has to be kept clean or fungus spores
will be spread throughout the produce.
Some fruit and vegetables need their outer leaves removed before storage. However, usually it is better to leave the
leaves on during storage to reduce moisture loss, and then remove them before sale.
Preliminary cooling (Precooling)
Dipping the produce in cool water to remove field heat can reduce the energy requirements of the store. However,
this can spread fungus spores throughout the produce. A suitable alternative is to pick the produce either early in
the morning when it is cool or late in the evening and leave it overnight to cool down.
Storage conditions
Temperature
All fruits and vegetables have a 'critical temperature' below which undesirable and irreversible reactions or 'chill
damage' takes place. Carrots for example blacken and become soft, and the cell structure of potatoes is destroyed.
The storage temperature always has to be above this critical temperature. One has to be careful that even though
the thermostat is set at a temperature above the critical temperature, the thermostatic oscillation in temperature
does not result in storage temperature falling below the critical temperature. Even 0.5°C below the critical
temperature can result in chill damage.
It can be seen from the table that there are basically three groups of fruit and vegetables: those stored at 0 - 4°C;
those stored at 4 - 8°C; and those that require a storage temperature above 8°C. It is often more convenient to
concentrate on one of these groups.
Relative humidity
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33. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
For most produce, a high but not saturated, relative humidity is required, eg 85 - 95%. Table 1 shows specific
relative humidities for fruits and vegetables. There is always some moisture loss during cold storage but excessive
moisture loss is a problem. It is essential that the relative humidity is kept above 85%. This can be done by:
• allowing the produce to reach storage temperature and then covering in plastic
• sprinkling the produce with water, this should be done before storage since if the vegetables are sprinkled during
storage condensation occurs at the refrigeration unit.
Packing system
A packing system is required so that the produce can be loaded and unloaded easily and safely. This can be a
system using crates that can be stacked or a more complicated system using racks and trays. It is important that the
crates are small enough to be moved easily when full of vegetables; are able to be easily and safely stacked; and
are strong enough to hold the weight of the other crates. It is essential that the airflow is not restricted, therefore a
two foot gap should be left between the walls and the crates and three foot gap left between the crates, the ceiling
and refrigeration units. Figure 1 shows the design of a crate that is suitable for cold stores. For small-scale cold
storage systems, stackable crates are the most appropriate packing system. Cold storage of fruit & vegetables
Practical Action
Length of storage
Table 1 gives the maximum storage times recommended by various organisations. These recommendations are
based on figures from Europe and America and are often for too long for small-scale stores in tropical countries for
the following reasons:
• It is often difficult to prevent delays between harvest and storage.
• The produce is often bruised during harvest and loading of the store.
• Transport can be bumpy and result in damage.
• The temperature of the retail outlets is far higher than for the retail outlets in Europe and America.
Incompatibility
If different produce is being stored in the same room there is a risk of transfer of odours or ethylene.
Y = No cross action SR = Slight danger BR = Danger
N = Cross action will take place
Table 2: Compatibility of storage
Operation of the cold store
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34. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
The cold store should be kept very clean and the doors opened as little as possible.
Transport
Care needs to be taken during the unloading of the cold store and during transport. If the produce can be
transported in the same crates they were stored in, handling and concomitant damage will be reduced.
Shelf life
The shelf life of the produce will not be as long as fresh produce but if the above recommendations are followed,
the reduction in shelf life can be as little as 10%.
Table 1. Fruits & Vegetables that require cold, moist conditions
Vegetable Temperature (o
F) Relative Humidity (%) Length of Storage
Asparagus 32-36 95 2-3 weeks
Apples 32 90 2-6 months
Beets 32 95 3-5 months
Broccoli 32 95 10-14 days
Brussels Sprouts 32 95 3-5 weeks
Cabbage, Early 32 95 3-6 weeks
Cabbage, Late 32 95 3-4 months
Cabbage, Chinese 32 95 1-2 months
Carrots, mature 32 95 4-5 months
Carrots, immature 32 95 4-6 weeks
Cauliflower 32 95 2-4 weeks
Celeriac 32 95 3-4 months
Celery 32 95 2-3 months
Collards 32 95 10-14 days
Corn, sweet 32 95 4-8 days
Endive, Escarole 32 95 2-3 weeks
Grapes 32 90 4-6 weeks
Kale 32 95 10-14 days
Leeks, green 32 95 1-3 months
Lettuce 32 95 2-3 weeks
Parsley 32 95 1-2 months
Parsnips 32 95 2-6 months
Pears 32 95 2-7 months
Peas, green 32 95 1-3 weeks
Potatoes, early 50 90 1-3 weeks
Potatoes, late 39 90 4-9 months
Radishes, spring 32 95 3-4 weeks
Radishes, winter 32 95 2-4 months
Rhubarb 32 95 2-4 weeks
Rutabagas 32 95 2-4 months
Spinach 32 95 10-14 days
Table 2. Vegetables that require cool, moist conditions
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35. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
Vegetable Temperature (o
F) Relative Humidity (%) Length of Storage
Beans, snap 40-50 95 7-10 days
Cucumbers 45-50 95 10-14 days
Eggplant 45-50 90 1 week
Cantaloupe 40 90 15 days
Watermelon 40-50 80-85 2-3 weeks
Peppers, sweet 45-50 95 2-3 weeks
Potatoes, early 50 90 1-3 weeks
Potatoes, late 40 90 4-9 months
Tomatoes, green 50-70 90 1-3 weeks
Tomatoes, ripe 45-50 90 4-7 days
Table 3. Vegetables that require cool dry conditions.
Vegetable Temperature (o
F) Relative Humidity (%) Length of Storage
Garlic 32 65-70 6-7 months
Onions 32 65-70 6-7 months
Table 4. Vegetables that require warm dry conditions.
Vegetable Temperature (o
F) Relative Humidity (%) Length of Storage
Peppers, hot 50 60-65 6 months
Pumpkins 50-55 70-75 2-3 months
Squash, winter 50-55 50-60 2-6 months
Sweet Potato 55-60 80-85 4-6 months
Requirements and general characteristics for a storage facility
Generally, storage facilities are linked or integrated to packinghouses or other areas where there is a
concentration of product. However, often storage can also be undertaken on-farm, either naturally or in specifically
designed facilities. Even under conditions of mechanical refrigeration, location and design have an impact on
system operations and efficiency. First, climate is an important factor for the location of the storage facility. For
example, altitude reduces temperature by 10 °C for every 1 000 meters of elevation. It also increases overall
efficiency of the refrigeration equipment by facilitating heat exchange with ambient temperature, thereby reducing
energy costs. Shading particularly of loading and unloading areas reduces thermal differences between field and
storage temperatures.
Building design is an important factor to be taken into consideration. For example, a square shaped floor
perimeter is thermally more efficient than a rectangular one. The roof is the most important part of the structure.
This is because it has to protect produce from rain and radiant heat. Its slope should allow easy fall off of
rainwater; its dimensions should exceed the perimeter of the building to protect walls from the sun and provide a
dry area around the building in rainy weather. Floors should be of concrete, isolated from soil humidity, and
elevated to avoid penetration of water. Doors need to be wide enough for mechanised handling.
Storage facilities should be thoroughly cleaned before filling. This includes brushing and washing of walls
and floors to eliminate dirt and organic debris that could harbor insects and diseases. Before product is placed in
the storage room, inspection and presorting should be undertaken. This is in order to remove all potential sources
of contamination for the remaining load. Product should be stacked in such a way that there is free circulation of
air. During storage, it should also be possible to carry out quality control inspections. If the storage facility
becomes full during a long harvest period, it needs to be organized around the principles of the system "first in first
out".
Factors to Consider
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36. HANDLING, TRANSPORTATION AND STORAGE OF FOODS, Notes Vol. 1.21 By:- Mohit Jindal
1. A Clean Storage Space-: Always keep the storage area clean of debris and discard fruits and vegetables as
soon as they begin to show signs of decay. Containers should be removed during the summer, washed and
dried in the sun.
2. Monitor the Temperature-: Monitor temperatures to avoid produce being destoyed by any exposure to low
or high temperatures, which can happen in extreme cases. Thermometers should be placed inside and
outside the storage facility. Stored produce will give off heat during storage making it necessary to regulate
temperatures by use of the ventilation windows. If the outside temperature is 25 degrees and the inside is
32 degrees with the ventilation windows closed, the temperature will begin to rise and windows should be
opened to lower the temperatures. Close theventilation windows when outside temperatures are above the
desired storage temperatures. Because certain crops are more sensitive to low temperature injury, learn
their freezing point. Most fall within a range of 29 to 31 degrees.
3. Regulate the Humidity-: Over time, vegetables and fruit will give up moisture and shrivel. Maintain proper
moisture levels during storage by regulating humidity. This can be done by increasing the water in the air
through humidifying or by using plastic bags and box liners for storage in individual crops. Humidification
is simply taken care of by sprinkling water inside the storage area, but not directly on the produce. For root
crops which lose moisture regardless of attempts to humidify with free water, placing them in plastic bags
is perhaps the best way to keep them fresh. Plastic liners and bags should be ventilated by creating holes.
Produce should never be sealed shut.
4. Handling Fruit and Vegetables-: Handle all produce with care to avoid wounds which become good sites
for storage diseases. Pick all produce dry or let dry before storage. Pack produce in plastic or wooden
baskets or boxes. Move the produce to the storage area when the field heat has been reduced. Harvesting in
the early morning or cooling overnight outdoors will help.
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