l3-care of cargo during carriage (part 2)

1

• Understand the importance of ventilationto prevent sweat damage to cargo duringcarriage

• Define "ship sweat" and "cargo sweat”

CARE OF CARGO DURING CARRIAGECARE OF CARGO DURING CARRIAGECARE OF CARGO DURING CARRIAGE

Sweat & Ventilation

p g• Understand how "ship sweat" and "cargo

sweat" sweat can occur and the actionsrequired to minimise their occurrence

• Describe the principle of forced ventilation

obs/2009 Slide 1

• To describe the operations of two types offorced ventilation and humidity controlsystems

• State reasons for the ventilation of cargod i i h h f h


Sweat & Ventilation

spaces during carriage other than for theminimisation of sweat

• Obtain information for special ventilationtechniques for the carriage of bulk coaland bagged rice

obs/2009 Slide 2

• Varying climates and temperatures

• Consequent effects on cargoes due

to heating and cooling


Sweat & Ventilation

to heating and cooling

• Excessive overheating – severe deterioration

• Rapid cooling – condensation, sweat

SP-SMAobs/2009 Slide 3

2

• Cargoes are mainly of two kinds ‐ Hygroscopic

& Non‐Hygroscopic

• Hygroscopic cargoes are mainly of vegetable

origin such as grain flour cotton tobacco


Cargo Effect

origin such as grain, flour, cotton, tobacco,

wood and the like, all of which are affected by

the humidity of the atmosphere, attracting,

retaining and giving off moisture

obs/2009 Slide 4

• Hygroscopic cargoes cause ship's sweat byvirtue of changes in temperature,particularly when passing from warm areasto cooler conditions.


Cargo Effect

• More prevalent with sudden falls in outsidetemperature.

obs/2009 Slide 5

Non‐Hygroscopic cargoes are mainly of

solid nature, such as steel products,

machinery, earthenware, canned goods and

the like, which can be subjected to damage


Cargo Effect

, j g

from cargo sweat (condensation)

in the form of rusting, staining and

discolouration.

obs/2009 Slide 6

3

NonNon‐‐HygroscopicHygroscopic

More prevalent if loading has taken

place in cold climates and the cargo

later subjected to warm climatic


Cargo Effect

later subjected to warm climatic

conditions, when internal condensation

is likely to be more applicable.

obs/2009 Slide 7

• Temperature changes in the cargo neednot be more than one or two degrees aday to activate sweat, irrespective oflarger outside temperature fluctuations.

NonNon‐‐HygroscopicHygroscopic


Cargo Effect

• When passing from cold to warm regionit may be advisable to seal off ventilatorsin order to avoid problems of sweat whichmay arise.

obs/2009 Slide 8

• Cold to Warm climatesCondensation on cargo ‐ Cargo sweat

‐ Stop ventilation• Warm to Cold climatesCondensation on ship’s structure

Sweat & VentilationSweat & Ventilation


Condensation on ship s structure ‐ Ship’s sweat‐ Allow ventilation.

• Others ‐ evolution of gases and odours by cargo may be absorbed by other cargo within the hold

obs/2009 Slide 9

4


Dew Point

obs/2009 Slide 10

Dew Point is the temperature to

which a sample of air must be


Dew Point

cooled for it to become saturated

MD/Aug07 SP-SMASlide 11obs/2009 Slide 11

• Condensation directly on to the cargo.Cargo sweat can arise when passing fromcolder to warmer climatic conditions, sincethe cause is from the warmer moistureladen air condensing on the cargo.


Cargo Sweat

g g

• Its prevention is by sealing off theventilating facilities, although extractorfans will be necessary to off‐set anymoisture effects emanating from the cargoitself, or its dunnaging materials.

obs/2009 Slide 12

5

18˚CDP14˚C

18˚C

23˚CDP18˚C

Cargo Sweat

Cease Ventilation

Cool to Warmer Atmospheric Conditions:Cargo Sweat

MD/Aug07 SP-SMA 13

18˚C

18˚C

28˚CDP21˚C

• Condensation on the ship's structure takesplace when the "DEW POINT“in a cargo space exceeds the temperature ofthe structural parts of the ship.


Ship’s Sweat

• It is minimised or eradicated, by passingadequate volumes of outside air over thecargo, more particularly necessary in vesselpassing from warm to cooler atmosphericconditions.

obs/2009 Slide 14

23˚C

18˚CDP 22˚CVentilates

Warm to Cooler Atmospheric Conditions:Ship’s Sweat

MD/Aug07 SP-SMA 15

DP 22˚C28˚C

23˚CDP 22˚C

Ship’s Sweat

6

CARGO CARGO

HYGROSCOPIC NON-HYGROSCOPIC


MAY CAUSESHIP’S SWEAT

MAY BE DAMAGEDBY CARGO SWEAT

VEGETABLE ORIGINGRAIN, FLOUR, COTTON

TOBACCO, WOOD

NON-VEGETABLE ORIGINCAN GOODS, MACHINERY

EARTHENWARE, STEEL

obs/2009 Slide 16

• A knowledge of hygrometry is essential tounderstanding sweat and its problems since itis concerned with retention of water vapour inconcentrations of air. The controlling factor isthe relationship between the temperature andhumidity of the air.


Hygrometer/Sweat/Dew Point

• Air having 100% humidity is said to be"saturated".

• The dew point is normally obtained by use ofwet and dry bulb thermometers, the readingsreferred to conversion table which give the dewpoint.

obs/2009 Slide 17

• Purpose is to remove heat, moisture,odours and dangerous gases from thecompartment.

• Lack of ventilation can result in largedamage claims due to deterioration, sweat,


Ventilation

gtaint or rust damage, and can also cause adangerous build‐up of poisonous andexplosive gases.

• Ventilation may be natural, forced ormechanical.

obs/2009 Slide 18

7

• In ventilating practice, the ship officer cancollect only limited evidence of holdatmospheric conditions through the use of"wet" and "dry" bulb temperature readings in afew locations in the holds and on the open


The “Rules” of Hold VentilationPractical Guidelines

few locations in the holds and on the opendeck.

• If there is any circulation of air in the hold itcan be assumed that the former will berepresentative of the overall hold conditionsunless the thermometers are placed close toventilator inlets.

obs/2009 Slide 19

• Wet and dry bulb readings are taken in afew locations in the holds and on the opendeck.

• From these readings the dew points are



g pobtained.

• Comparing the dew points of hold air andthe outside air enables decisions to betaken as to weather or not to continueventilating.

obs/2009 Slide 20

• If the dew point outside is lower or equal to that of the hold dew point…............. continue ventilation



• If the dew point outside is higher than the hold dew point ................ do not ventilate with outside air

obs/2009 Slide 21

8

OUTSIDE DEWPOINTLESS THAN OR

EQUAL TOHOLD DEWPOINT

OUTSIDE DEWPOINT

GREATER THANHOLD DEWPOINT


Ventilation of Cargo Holds

CONTINUEVENTILATION

CEASEVENTILATION

obs/2009 Slide 22

Hygroscopic Cargoes

• Not critical, therefore ventilation not

essential.


Cold to Warm Voyage

• On opening hatches at destination

immediate condensation may form a

surface but will dry off when cargo is

discharged.

obs/2009 Slide 23

Dry = 25˚CWet = 20˚C


Wet = 20 CRH = 65 %

DP = 17½˚C

0.013

obs/2009 Slide 24

9

Hygroscopic Cargo

• Highly critical (eg. tropical produce enroute to U.K.).

• Ventilation should be as vigorous as


Warm to Cold Voyage

possible during the early stages buteventually the outside dew point will betoo low.

• This is most difficult voyage situation inwhich to arrange satisfactory ventilation.

obs/2009 Slide 25

Non‐Hygroscopic Cargo

No ventilation; cargo sweat wouldoccur on the surface of the stow ifrelatively warmer moisture laden air


Cold to Warm Voyage

relatively warmer moisture laden airwas admitted. Ex ..... steel exports U.K.to tropical ports.

obs/2009 Slide 26

Non‐Hygroscopic Cargo• Ship sweat inevitable but cargounaffected unless condensation dripsback on to the stow.

• It is emphasized that the above


Warm to Cold Voyage

pguidelines are only basic.

• The proximity of both types of cargo inthe same space will cause modificationsto achieve a satisfactory balance ofventilation effectiveness.

obs/2009 Slide 27

10

A ventilation and humidity control system

comprising of:

Hold fans and duct system

Instruments for recording outside


Mechanical Ventilation

Instruments for recording outside and inside wet and dry bulb temperatures

A dehumidifier, a machine for removing moisture from the air.

obs/2009 Slide 28

Cargo Caire & Drihold• Designed to enable the space to be ventilatedin the normal way, or to be an enclosedsystem of re‐circulation with dry air addition.

• If the dew point of the outside air is lower


Mechanical Ventilation

pthan the dew point of the inside air, thesystem should be set to ventilate.

• If the dew point outside is higher than theinside dew point, the system should be set torecirculate and add dry air.

obs/2009 Slide 29

Advantages of MechanicalAdvantages of MechanicalVentilation Over Natural VentilationVentilation Over Natural Ventilation

• Increase of air flow• Re‐circulation and drying air to prevent cargosweat.

• Avoiding ship's sweat when weather restrictst l til ti


natural ventilation,• Drying holds after washing.• Drying deep tanks after ballast.• Drying parcel of cargo that have become wet byrain.

obs/2009 Slide 30

11

• As the ship proceeds on her voyage therewill be some transfer of moisture throughthe stowed cargo. This movement is calledmoisture migration.

• It has been found that moisture migration


Moisture Migration

gcoupled with ship's sweat can result indamage to cooler parts of the cargo unlessthe excessive moisture can be removed.

• Adequate dunnage to protect cargo fromcontact with steelwork is vital.

obs/2009 Slide 31

To enable a more detailed consideration of the

conditions in the hold and outside, six

temperatures are relevant.

1O t id Ai T & 2D P i t


Moisture Migration

• 1Outside Air Temp & 2Dew Point

• 3Hold Temp & 4Dew Point

• 5Sea Temperature

• 6Temperature of Cargo Mass

MD/Aug07obs/2009 Slide 32

MECHANICALMECHANICALVENTILATIONVENTILATION

FAN & DUCTFAN & DUCTSYSTEMSYSTEM DEHUMIDIFIERDEHUMIDIFIERINSTRUMENTSINSTRUMENTS

DRIHOLDDRIHOLD

CARGOCAIRECARGOCAIRE

Advantages:• Increase air flow• Re‐circulation & dry air to prevent sweat• Avoid ship’s sweat when weather restrictnatural ventilation

• Dry holds after washing• Dry deep tanks after ballast• Dry cargo that is wet by rain

obs/2009 Slide 33

12

• System of cargo space ventilation and

humidity control is designed to enable the

cargo spaces to be ventilated by outside air


The Drihold System for the Prevention of Sweat

• Or sealed off from outside air as required, to

prevent ship's sweat or cargo sweat

respectively.

• Apparatus for dehumidifying the air in the

hold is also introduced.

obs/2009 Slide 34

Equipment consists of a Drihold VentilatingUnit having• a reversible fan which enables the unit to supplyfresh air to the cargo space, or exhaust thevitiated air from the cargo space.d i it h th i t i d d


The Drihold System

• drying unit, where the moisture is condensedout from the air by means of dehumidifyingcoils, fed with cold brine from a refrigeratingplant.

• A heat exchanger, arranged over the coils, warmsup the chilled air leaving the dehumidifying coilsby extraction of heat from the air entering thedrier

obs/2009 Slide 35

• When VENTILATING, (Dew Point ofoutside air is lesser than Dew Point ofspace), the air is drawn through the naturalventilator and passed around the space tobe exhausted by the Drihold unit anddelivered to atmosphere.


The Drihold System

delivered to atmosphere.• An arrangement of valves in the Driholdunit enables the cargo space to be sealed offfrom the atmosphere, under whichconditions the fan in the unit drawsentirely from the space and returns air tothe space to be recirculated continuously.

obs/2009 Slide 36

13

• The Air Drying Unit can then be introducedinto the air circuit in order that any moistureemanating from the cargo may be condensedout and thus prevent the Dew Point fromrising in the cargo space.T D P i i i i


The Drihold System

• Two Dew Point sensitive instruments, one;outside air, and the other air‐cargo space,(dial, pointer), indicates whetherVENTILATION should be adopted, or theholds sealed and RECIRCULATION OF THEAIR,with drying introduced.

obs/2009 Slide 37

The The DriholdDrihold System System


Condensed out any cargo moisture

Extract heat

Ventilate-Dew Point outside air less than cargo space

Recirculate-Dew Point outside air higher than cargo space

obs/2009 Slide 38

The The DriholdDrihold SystemSystem

Cold Brine Circulation

Warm Damp Air

High Dew Point

Dry Air

Low Dew Point

Baffle

Heat Exchange

Cool Dry


Cool DryAir

Pressure TrapDrain Condensation

Drying Unit

obs/2009 Slide 39

14

• Very similar to the drihold system, i.e. depending Upon the relevant dew points, either to ventilate or recirculate

• Major difference is in the method used toextract moisture and to dry the air when

l


The Cargo‐Caire

using recirculation • Drying agent used is silica gel, inert glass

like substance with the composition of quartz, having the ability to remove considerable quantities of moisture from the air

obs/2009 Slide 40

• The silica gel can be used over and overagain and need never be replaced providedit is kept clean.

• In the dry air unit, the silica gel is enclosed


The Cargo‐Caire

in cylindrical containers arranged in twosets, so that while one set is drying air fromthe holds, the other is having its entrappedmoisture removed.

obs/2009 Slide 41

The figure below shows diagrammatically the flow ofair through the dry air unit and how the air flow iscontrolled by four way valves.


"CARGO CAIRE" mechanical ventilation system - Air flow diagram

obs/2009 Slide 42

15

5

7

De-humidifying Cycle

Re-activation Cycle

Silica Gel Silica Gel

To Cargo Hold

Air Cooler

Upper 4-Way Valve

Re-activationAir Heater

4


6

1

Silica GelBed 3

Silica GelBed 8

Lower 4-Way Valve

Re-activationFan

FromAtmosphere

To Atmosphere

From Cargo Hold or Atmosphere Absorption Fan

2

obs/2009 Slide 43

• Air to be dried is drawn into the unit througha set of filters by the absorption fan (1) and carried to the lower four‐way valve (2).

• With the valve in the position shown, the airis diverted to the bottom of the pair of silica gel beds (3) on the left of the diagram


The Cargo‐Caire

gel beds (3) on the left of the diagram. • The air is dried as it flows from the bottom up and through the gel beds and to the upperfour‐way valve (4).

• The baffle in the valves diverts the flow of airover the cooler (5) and out to the dry air duct, which carries it to the hold.

obs/2009 Slide 44

• Simultaneously, the pair of gel beds (8) on theright of the diagram is being reactivated.• Air is drawn through a set of filters into the unitby the reactivation fan (6) and passes over thereactivation air heater (7) to the upper four‐wayvalve (4).


The Cargo‐Caire

(4)• Here the valve baffle diverts the hot air to the topof the gel beds (8) which are dried by forcing theair down and through the silica gel.• The wet air is passed from the bottom of thebeds to the lower four‐way valve (2) where it isdiverted to the wet air duct and discharged to theatmosphere.

obs/2009 Slide 45

16

• After an hour of operation with the beds (3) onthe absorption phase and the beds (8) on thereactivation phase, the electric timer makescontact to operate the valve changing motor.

• This rotates the sprockets on the two‐wayvalves through 1800 and the valves in their new


The Cargo‐Caire

gpositions reverse the air flow through each pairof beds.

• Beds (3) are then being reactivated and beds(8) are supplying dry air. In this way there is acontinuous, automatic flow of air through theunit, ensuring a constant supply of dry air forthe hold circulating systems.

obs/2009 Slide 46

Ventilation with Specific CargoesVentilation with Specific Cargoes

• Some cargoes ‐ chemical reactions occur

• Constitute a source of danger from fire and

explosion, contaminate or deteriorate other

bl


susceptible cargo

• All reaction products‐water vapour, gases,

fumes , odours etc must be removed by the

only practical method ‐ ventilation

obs/2009 Slide 47

Coal Cargo• Evolves methane, which in ad‐mixture withcertain proportions of air will ignite with aspark‐coal mine

• Coal is liable to spontaneous combustion



Coal is liable to spontaneous combustioncaused by a chemical reaction with oxygen

• All cargo battens (spar ceilings) removed,ventilation trunks to hold bottom shut off.

• Adequate ventilation provided, no smokingsign placed.

obs/2009 Slide 48

17

Grain cargoes• Germination due to temperature andmoisture

• Through ventilation essential



• Saturated air with water vapour removed bycurrent of drier air

• Ventilation to adjust hold temperature tothat of outside air

obs/2009 Slide 49

Rice• Gives off moisture, heat odour and carbondioxide.

• Through ventilation essential to preventcargo damage



Fruit Cargo• Accurate control of temperature ‐deterioration occur

• Ventilation using cooling system, maintaincirculation

obs/2009 Slide 50

Clementines belong to the rue family(Rutaceae) and come originally from southernChina.

They are a cross between the mandarin (Citrusti l t ) d th S ill (Cit

Product DescriptionProduct Description


reticulata) and the Seville orange (Citrusauratium)

They are an easily peelable ("Easypeeler"),moderate‐sized, ellipsoidal orange citrus fruitcontaining no or few seeds.

obs/2009 Slide 51

18

In addition to oranges, the group of citrus

fruits, which are mainly cultivated in

subtropical regions, also includes lemons,



grapefruits, mandarins, limes and easypeelers.

Easypeeler is the name given in particular to

crosses between oranges and mandarins whose

peel is very easy to remove.

obs/2009 Slide 52

Citrus fruits are berry fruit consisting of three layers:

The outer yellow/orange peel (exocarp, flavedo),

Th l d f hi h d th ti l il



The glands of which exude the essential oils, which produce the typical citrus odor

The whitish mesocarp (albedo) the endocarp consisting of 8 ‐ 10 segments filled with juice sacs (vesicles)

obs/2009 Slide 53

The degree of ripeness of citrus fruit is determined on the basis of three criteria:By the ripeness index: This is determined by the Brixvalue, which is a measure of the sugar/acid ratio of the fruit. Citrus fruit with a Brix value of between 10 and 16 have good flavour.

Product DescriptionProduct DescriptionCARE OF CARGO DURING CARRIAGECARE OF CARGO DURING CARRIAGECARE OF CARGO DURING CARRIAGE

By cutting at purchase: Freshness is determined by cutting the fruit in half from the stem‐end to the opposite end. If the fruit is withered at the stem‐end, it must not be shipped. By peel colour: The colour of the peel is not necessarily a reliable indicator of ripeness, but its surface gloss is.

obs/2009 Slide 54

19

The presence of stem and green leaves on theproduct does not indicate impaired quality.Green leaves are a sign of freshness andshould be regarded as promoting sales.

Experience has shown that it is the care taken

QualityQuality / Duration of Stowage/ Duration of Stowage


Experience has shown that it is the care takenwith preparation of the fruit for shippingwhich very largely determines whetherindividual batches withstand the rigors oftransport.Such preparation for shipping is carried out inpacking houses.

obs/2009 Slide 55

This include post‐ripening of green orunsatisfactorily coloured fruit to achieve asaleable peel colour in ripening rooms.Removal of dirt, sooty mould, sprayingresidues and scale insects in washers.Coating with a layer of wax and treatment

h d k d l



with preservatives and marking accordingly.Grading of the fruits by size (gaging), colourand other external features.Counting, weighing and packing. Markingeach package with details of number of fruit,quality class, variety and origin.Storage until shipment in cold stores.

obs/2009 Slide 56

Waxing to prevent loss of aroma and weight

is required because the washing process

removes the natural wax layer.



The film of wax sprayed onto the peel only

partially seals the pores so that the fruits are

still able to respire.

MD/Aug07 SP-SMASlide 57obs/2009 Slide 57

20

Temperature Rel. humidity Max. duration of storage Source

6 - 9°C 85% 12 weeks [1]


Maximum Duration Maximum Duration of Stowage & Transportof Stowage & Transport

4.4°C not stated 2 - 4 weeks [39]

obs/2009 Slide 58

Clementines are highly pressure‐ andimpact‐sensitive and appropriate caremust therefore be taken during cargohandling.

The cold chain must at all costs be


Cargo HandlingCargo Handling

The cold chain must at all costs bemaintained, since otherwise there is a riskof rapid spoilage.

In damp weather (rain, snow), the cargomust be protected from moisture, as thereis otherwise a risk of premature spoilage.

obs/2009 Slide 59

2.2 m3/t (12 kg fruit crates)

The stowage factor depends very much


Stowage FactorStowage Factor

The stowage factor depends very muchon weight categories and thepackaging units used.

obs/2009 Slide 60

21

Stowage space requirementsCool, dry, good ventilation

SegregationMarker pen/oil crayon, segregating nets

Cargo securingBecause of its considerable impact‐ and pressure‐


Because of its considerable impact and pressuresensitivity, packages of this cargo must be secured in such a way that they are prevented from damaging each other. Spaces between packages or pallets must be filled, to prevent slippage or tipping. By selecting the correct packaging size or cargo unit, holds can be tightly loaded (without spaces).

obs/2009 Slide 61

• The holds or containers must be appropriately pre‐cooled before loading is begun.The pulp temperature should not be < 4°C or > 25 ‐ 30°C as storage life and appearance are impaired outside this range.


LoadingLoading

are impaired outside this range. • Fruits punctured for pulp temperature measurement must be discarded as they would rapidly spoil and infect the other fruit.

• The measured values should be recorded in all cases in order to preserve evidence

obs/2009 Slide 62

Clementines require particular temperature,humidity/moisture and ventilation conditions.Recommended ventilation conditions:circulating air, 60 ‐ 80 circulations/hour withcontinuous supply of fresh air.The addition of fresh air is extremely important


VentilationVentilation

y pas citrus fruit can start to ferment within a fewhours due to anaerobic respiration (resulting intotal loss of the fruit).If ventilation is inadequate, storage damagemay occur, taking the form of a bitter flavourand peel scab.

obs/2009 Slide 63

22

In fresh fruit, metabolic processes continue evenafter harvesting.The fruit absorbs oxygen (O2) and excretesvarying amounts of carbon dioxide (CO2) andethylene (C2H4) as well as aromatic compoundsduring the ripening process.


Fresh FruitsFresh Fruits

g p g pIf ventilation has been inadequate (frost) or hasfailed owing to a defect, life‐threatening CO2concentrations or O2 shortages may arise.Therefore, before anybody enters the hold, itmust be ventilated and a gas measurementcarried out.

obs/2009 Slide 64

The TLV for CO2 concentration is 0.49 vol.%.

Levels of respiratory gases which promoteripening, such as ethylene as well as carbondioxide, should be kept as low as possible.

If ventilation is inadequate storage damage


Fresh FruitsFresh Fruits

If ventilation is inadequate, storage damage,such as a bitter flavour and peel scab, mayoccur.

The supply of fresh air must thus be constantin order to dissipate these gases.

obs/2009 Slide 65

• Due to their high content of highly volatileessential oils (formic and acetic acid, ethenal,ethylene and the odour substance limonene),citrus fruits are in general a highly odour‐contaminating cargo and must thus not bestowed or stored together with fruit, vegetablesand other odour sensitive foodstuffs


ClementinesClementines: Strong pleasant odour: Strong pleasant odour

and other odour‐sensitive foodstuffs.• Meat, butter, eggs, fats and cheese areparticularly prone to absorbing the citrus odour.

• Cold stores must therefore be carefullydeodorized before different goods aretransported on the next voyage.

• Wooden dunnage tainted with the citrus odourmust not be reused for odour‐sensitive goods.

obs/2009 Slide 66

23

Blue mould rot or storage rot is the most feared storagedisease of citrus fruits and is caused by two species ofmould: green mould (Penicillium digitatum), which is ofan olive‐green colour, and blue mould (Penicilliumitalicum), which is of a blue‐green colour.The fungal spores mainly penetrate through smallinjuries and initially form white, circular spots of fungalgrowth which are subsequently covered from the centre


Insect Infestation / DiseasesInsect Infestation / Diseases

growth, which are subsequently covered from the centreoutwards with a green or blue‐green sporulating layer.The peel becomes spongy, the pulp soft ‐ a typicalinstance of wet rot.Development is optimal at 20 ‐ 27°C; growth stillflourishes at 10°C and comes to a standstill only at 4°C.Blue mould is transferred from fruit to fruit by contact.Seawater, rain and condensation water promote greenand blue mould growth.

obs/2009 Slide 67

• They are living organisms, they respire evenafter harvesting.

• Respiration is part of the natural ripeningprocess.

• During respiration, they generate heat and


Fruits & VegetablesFruits & Vegetables

give off gases and moisture that will speedup deterioration as well.

• Controlling the following factors can reducedeterioration of perishables.

obs/2009 Slide 68

• Is the most powerful and effective way tominimize deterioration.

•The faster the proper temperature is reached,the longer the expected life of the product.

• Cooling of fresh produce should begin asquickly as possible after harvest.


Cooling the TemperatureCooling the Temperature

quickly as possible after harvest.• Reefer containers should not be used toreduce the temperature of the cargo. Instead,they are designed to maintain rather than tolower the temperature of the cargo.

•Therefore, pre‐cooling all perishable productsimmediately after harvest and beforeshipment or storage is essential.

obs/2009 Slide 69

24

Relative humidity directly affects thequality of almost all products.If humidity levels are too low, fruits,vegetables and related products may wilt

h i l


HumidityHumidity

or shrivel.If relative humidity is too high, mouldmay develop to deteriorate the cargo.

obs/2009 Slide 70

Another way to minimize deterioration is toremove the ethylene gas.Ethylene, a self‐generating fruit‐ ripeningregulator, is necessary for the ripening offruits and vegetables.


EthyleneEthylene

gHowever, it can also cause damage to variousfruits, vegetables if it is not controlled inminimal level.We can minimize and control itsaccumulation by adequate ventilation.

obs/2009 Slide 71

Poor circulation can affect thecommodity’s temperature, relativehumidity and ethylene accumulation.

If the air cannot circulate properly in the


Air CirculationAir Circulation

If the air cannot circulate properly in thecold room or container, shelf life of theproduct will be definitely affected

obs/2009 Slide 72

25


Air CirculationAir Circulation

obs/2009 Slide 73

It is important that the packaging must allow airto circulate freely through the commodity,around the periphery of the container and in thearea of the door.The important criterion here is to have uniformdistribution of air throughout the load.


PackagingPackaging

This requires the cargo to be uniformly stowed.Different sized packaging obviously dictatesdifferent stacking patterns.The dimensions of loose cartons will inevitablynot be sized to fit the container exactly so theresulting gap must be kept in proper location.

obs/2009 Slide 74

Don't load pallets or cartons up to ceiling height,which will restrict air flow along the return airpassage over the top of the cargo to the evaporatorfan.Marine containers are marked with a height limit.This should never be exceeded.Wh di i il i d k i i d


PackagingPackaging

Where dissimilar sized packaging is used, orcargoes do not fill the container fully, it isrecommended that additional empty cartons orsome other material is used to fill up the voidspace so that the air passages remain uniform.In order to have optimal air circulation andcooling effect. It's advisable to pack commoditywith carton and make holes in cardboard all sides.

obs/2009 Slide 75

26


LoadfingLoadfing Pattern in reefer ContainerPattern in reefer Container

obs/2009 Slide 76


obs/2009 Slide 77

Mixing fresh products in a single reefer is veryimportant in their compatibility.If carrying temperature is too low or too highto one product could cause cargo damage.

Shi h ld l b f h


Shipper should also be aware of therespiration levels and ethylene produced bythe commodities at certain temperatures andmaturity levels and & their degree oftolerance or sensitivity to those ethylene.

obs/2009 Slide 78

l3-care of cargo during carriage (part 2)

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