Apples [German version]

Table of contents

General:
Product information
Packaging
Transport
  Container transport
  Cargo securing


Risk factors and loss prevention:
Temperature Odor
Humidity/Moisture Contamination
Ventilation Mechanical influences
Biotic activity Toxicity / Hazards to health
Gases Shrinkage/Shortage
Self-heating / Spontaneous combustion Insect infestation / Diseases




Product information

Product name

German Äpfel
English Apples
French Pommes
Spanish Manzanas
Scientific Malus sylvestris var. domestica
CN/HS number * 0808 ff.


(* EU Combined Nomenclature/Harmonized System)



Product description

Apples (rose family, Rosaceae) are a pomaceous false fruit with whitish, firm pulp and a generally sour-sweet flavor. The small brown seeds (pips) are located in a parchment-like core with 5 compartments. The apple tree originated between the Black Sea and the Caspian Sea and spread to all temperate zones of the world.

Numerous apple varieties have been developed over the several thousand years that they have been cultivated. Taste and color differ depending on the variety and stage of ripeness.

A distinction may be drawn between dessert fruit (fruit for eating fresh), commercial fruit (industrial use, e.g. for apple puree, apple jelly and obtaining pectin) and cider apples (apple juice, wine).

Apples are divided into summer, autumn and late varieties (keeping apples) depending on when they ripen: the latter are the most common.

Apples are available all year round owing to their different ripening times and long-term storage as well as imports from the southern hemisphere.

Examples of well-known varieties are:

"Boskoop"
"Cox's Orange"
"Golden Delicious"
"Jonagold"
"Gravensteiner"


Quality / Duration of storage

Apples are shipped at the preclimacteric stage (tree or picking ripe). The skin must exhibit lightening of the ground color and the pulp must be green.

Apples are transportable if free from spoilage, damage, bruises and abnormal moisture. In addition, they must be free from diseases and pests.

To determine the degree of ripeness of pomaceous fruit, the hardness of the pulp is measured using a pressure tester, which involves pressing a cylindrical steel plunger into the pulp. The maximum pressure is read off in pounds. At the preclimacteric stage, the reading for most varieties of apple lies between 18 and 20 pounds. During ripening, hardness decreases by 5 - 6 pounds. Pulp temperature measurements are also performed, as with citrus fruits.

Size grading is generally performed mechanically. If grading is performed by hand, gaging rings or gaging boards are used. Dessert apples are divided into three quality classes: extra, I and II.

They may be stored for between 1 and 6 months, depending on variety and degree of ripeness.

Where controlled atmosphere transport is used, transport and storage duration may be extended to approx. 8 months. The following parameters apply in such a case [16]:

Temperature Rel. humidity O2 CO2 Suitability for controlled atmosphere
1.1 - 4.4°C 90 - 95% 2 - 3% 1 - 2% very good



Intended use

Apples are the main type of fruit consumed fresh in Germany. They are also used in preparing salads, cakes, dishes of raw fruit and vegetables, jams etc..


Figures

(Click on the individual Figures to enlarge them.)

Photo, apples

Figure 1
Drawing, apple

Figure 2



Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Europe Germany, France, Denmark, Italy, Netherlands, Russia, Greece, Spain, Belgium
Africa South Africa
Asia China
America Argentina, Chile, USA
Australia Australia, New Zealand


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Packaging

Apples are transported in crates and cartons. Jointed boxes are made from resin-free wood (standard softwood boxes), to prevent odor tainting, and are strong. Package weight and dimensions are generally very variable.


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Transport

Symbols

Symbol, general cargo

General cargo


Temperature-controlled



Means of transport

Ship, aircraft, truck, railroad


Container transport

Refrigerated container with fresh air supply or controlled atmosphere


Cargo handling

Because of its impact- and pressure-sensitivity, the fruit has to be handled with appropriate care.

The required refrigeration temperature must always be maintained, even during cargo handling.

In damp weather (rain, snow), the cargo must be protected from moisture, as there is otherwise a risk of premature spoilage.


Stowage factor

2.37 m³/t (boxes, cartons) [1]
2.37 - 3.21 m³/t (boxes, cartons) [11]
2.52 - 2.89 m³/t (boxes, cartons) [14]



Stowage space requirements

Cool, dry, good ventilation


Segregation

Marker pen, oil crayon, fiber rope, thin fiber nets


Cargo securing

Because of its considerable impact- and pressure-sensitivity, 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 (area module or area module multiple), holds can be tightly loaded (without spaces).

Photo, cargo securing

Figure 3



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Risk factors and loss prevention

RF Temperature

Apples require particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

A written cooling order must be obtained from the consignor before loading is begun. This order must always be complied with during the entire transport chain.

The following Tables merely constitute an estimate of appropriate temperature ranges. Temperatures may deviate from these values, depending on the particular transport conditions.

Designation Temperature range Source
Travel temperature    
Cold-insensitive varieties 0 - 2°C [1]
0.5 - 1°C [11]
-1 - +1°C [39]
Cold-sensitive varieties 4.5°C [11]
2 - 5°C [39]


The refrigeration temperature is highly dependent on the different varieties and their susceptibility to internal breakdown.

Internal breakdown suggests excessively rapid cooling. Internal breakdown is the most frequent type of chilling damage in apples. It occurs at temperatures of around 0°C and is not generally visible from the outside. The pulp displays irregularly dispersed streaky brown marks and becomes mealy, with the consistency of the fruit becoming elastic. The riper side of the fruit generally suffers more than the greener side.

Freezing injury in apples may be recognized by watery, deep brown-colored flesh after thawing.

Supply air should never be < -1°C.


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RF Humidity/Moisture

Apples require particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

Designation Humidity/water content Source
Relative humidity 85 - 90% [1]
90 - 95% [39]
Water content 82 - 83% [1]
Maximum equilibrium moisture content 85% [1]


At a rel. humidity > 90% there is a considerable risk of mold development.


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RF Ventilation

Apples require particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

Recommended ventilation conditions: circulating air, 40 - 60 circulations/hour with continuous supply of fresh air

The spoilage symptom storage scald indicates insufficient air exchange in the hold and is caused by an apple's own excretion products in the event of inadequate ventilation. This disease is manifested externally by discoloration of the skin.


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RF Biotic activity

Apples display 2nd order biotic activity.

They are living organs in which respiration processes predominate, because their supply of new nutrients has been cut off by separation from the parent plant.

Care of the cargo during the voyage must be aimed at controlling respiration processes (release of CO2, water vapor, ethylene and heat) in such a way that the cargo is at the desired stage of ripeness on reaching its destination. Inadequate ventilation may result in fermentation and rotting of the cargo as a result of increased CO2 levels and inadequate supply of atmospheric oxygen (see Ventilation).


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RF Gases

CO2 evolution 2.0 - 7.0 mg/kg*h [1]
Upper limit of permissible CO2 content 1.0 vol.% [1]

2.0 vol.% [11]

0.4 vol.% [14]

< 0.8 vol.% [39]
Ethylene evolution  
Active behavior Climacteric apples exhibit high levels of ethylene production (> 100 µl/kg*h) [16]. Early and late apple varieties should not be stowed together, since this may reduce the storage life of the late varieties. Bananas are also at considerable risk. Even where apples and bananas are stowed in different compartments of an ocean-going vessel, the turbulence caused by the return and fresh air fans may cause the bananas to ripen prematurely.
Passive behavior The sensitivity of apples to ethylene may be classified as high [16]. They must not therefore be stored together with ethylene-producing goods (allelopathy).


In fresh fruit, metabolic processes continue even after harvesting. The fruit absorbs oxygen (O2) and excretes varying amounts of carbon dioxide (CO2) and ethylene (C2H4) as well as aromatic compounds during the conversion of starch into sugar (ripening process).

If ventilation has been inadequate (frost) or has failed owing to a defect, life-threatening CO2 concentrations or O2 shortages may arise. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out. The TLV for CO2 concentration is 0.49 vol.%.


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RF Self-heating / Spontaneous combustion

No risk.


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RF Odor

Active behavior Apples have a strong, pleasant odor.
Passive behavior Apples are very odor-sensitive and should not be stowed together with goods such as meat, butter and cheese.



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RF Contamination

Active behavior Apples do not cause contamination
Passive behavior Apples are sensitive to dust, dirt, fats and oils. Clean packaging is absolutely essential, since the cargo may spoil very rapidly as a result of mold or bacterial attack. The holds or containers must accordingly be clean and in a thoroughly hygienic condition before loading.



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RF Mechanical influences

Apples are very sensitive to impact. The fruit must be handled very carefully, since, in the event of strong pressure or jolting/vibration, the fruit rapidly succumbs to bruising and may start to rot within just a few days. According to [14], no more than 10 - 12 cartons should be stowed on top of one another.

Where possible, the apples should be of uniform size to even out pressure and prevent damage. Size grading is generally performed mechanically. If grading is performed by hand, gaging rings or gaging boards are used. Dessert apples are divided into three quality classes: extra (minimum diameter 65 mm), I (minimum diameter 60 mm) and II (minimum diameter 55 mm).

Photo, gaging

Figure 4
Drawing, apple

Figure 5



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RF Toxicity / Hazards to health

If ventilation has been inadequate (frost) or has failed owing to a defect, life-threatening CO2 concentrations or O2 shortages may arise. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out. The TLV for CO2 concentration is 0.49 vol.%.


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RF Shrinkage/Shortage

The normal weight loss due to a reduction in the moisture content of the product is < 1% [1], but according to [39] may be 3 - 5% for some varieties.

Added to this are losses of volume caused by packaging breakage, which should not however be greater than 0.4% [2].


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RF Insect infestation / Diseases

The most important storage diseases are:

Storage scald: the spoilage symptom storage scald indicates insufficient air exchange in the hold and is caused by an apple's own excretion products in the event of inadequate ventilation. This disease is manifested externally by discoloration of the skin.
Internal breakdown: internal breakdown suggests excessively rapid cooling. Internal breakdown is the most frequent type of chilling damage in apples and is not generally externally visible. The pulp displays irregularly dispersed streaky brown marks and becomes mealy, with the consistency of the fruit becoming elastic. The riper side of the fruit generally suffers more than the greener side.
Brown heart: this condition, identifiable from a dark core, may arise as a result of an excessively high CO2 content in the hold air.


Photo, brown heart

Figure 6


Bitter pit: brown, bitter-tasting spots appear just under the skin, as a result of metabolic disorders.
Rot, e.g. brown rot caused by Monilia fructigena. It is manifested by brown spots and tufts of yellowish spores, which are typically arranged in circles. Like brown rot, gray and blue (mold) rot are also caused by molds.


Photo, blue mold rot

Figure 7
Photo, apple scab

Figure 8
Photo, brown rot

Figure 9


Chewing and sucking injuries are caused by the following apple pests:

fruitworm
codling moth
apple fruit moth
apple sawfly
apple psylla
summer fruit tortrix moth
apple-and-thorn skeletonizer
scale insects etc.


The quarantine regulations of the country of destination must be complied with and a phytosanitary certificate may have to be enclosed with the shipping documents. Information may be obtained from the phytosanitary authorities of the countries concerned.


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