Grapes [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 Weintrauben (Tafeltrauben)
English Grapes
French Grappes de raisin
Spanish Uvas
Scientific Vitis vinifera
CN/HS number * 0806 10 ff.


(* EU Combined Nomenclature/Harmonized System)



Product description

Grapes (Vitis vinifera L.) are berry fruit belonging to the grapevine family (Vitaceae). Grapes come originally from south-west Asia.

Grapes are cultivated on vines (climbing shrubs). Dessert grapes are very carefully cut by hand and individual sick or damaged berries are removed. They are harvested at full ripeness, i.e. at the climacteric stage, as they do not post-ripen well after harvesting at the preclimacteric stage. The „Brix“ value is used to determine the time of harvest.

The berries on the panicles (commonly known as „bunches“) are usually covered by a whitish wax layer or bloom which can easily be wiped off and provides natural protection.

Before being eaten, dessert grapes should be washed thoroughly in order to remove any traces of spray.

Grapes are cultivated in the open, under glass (Belgium, Netherlands) and in plastic tunnels. Cultivation under glass and in tunnels allows harvesting times to be extended.

The following varieties may be distinguished:

White varieties (green, yellow to amber-colored varieties)
Dark varieties (red, blue to black varieties) which get their color from anthocyanins (oenin)
Waltham Cross grapes, so named because they were first exported to South Africa from the English town of this name. These have a stronger skin, are not so tightly packed on the bunch and are thus less susceptible to spoilage
Muscat grapes, which have a musky aroma, which occur as both white and dark varieties
Varieties with up to 5 seeds, although the seedless varieties are more popular


Quality / Duration of storage

Grapes awaiting transport should be sound, fresh, exhibit no foreign odors or flavors, be free of abnormal moisture, have no pressure marks or bruises, should not include any burst or shriveled grapes or any which have fallen from the bunch, nor exhibit any fungal growth or dried out stems. Grapes to be eaten fresh (dessert grapes) must have reached their full ripeness and color and must not be withered.

Seedless varieties are considered to be of higher quality and are therefore particularly popular with consumers.

Various sources state maximum duration of storage as follows:

Temperature Rel. humidity Max. duration of storage Source
-1 – 0°C 90% 4 weeks [1]
1 – 4°C 90 – 95% 8 weeks [3]
-1 – -0.5°C 90 – 95% 8 – 24 weeks (depending upon variety) [5]


Where controlled atmosphere transport is used, the transport and storage duration of the grapes may be extended. The following parameters apply in such a case [16]:

Temperature Rel. humidity O2 CO2 Suitability for controlled atmosphere
1.1 – 2.2°C 90 – 95% 3 – 5% 1 – 3% Moderate



Intended use

Dessert grapes are principally intended to be eaten fresh.


Figures

(Click on the individual Figures to enlarge them.)

Photo, black grapes

Figure 1
Photo, white grapes

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 Turkey, Spain, Italy, France, Hungary, Romania, former Yugoslavia, Bulgaria, Greece, Cyprus, Belgium, Portugal
Africa South Africa
Asia Israel
America Chile, Argentina, Brazil, USA
Australia Australia, New Zealand


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Packaging

Grapes are packaged in crates, fruit crates and cartons, each containing 10 kg. Particularly high quality grapes are individually wrapped or packaged in shaped trays in cartons lined with wood wool or in perforated polyethylene film in fruit crates.

Packaging should be treated against mold attack.


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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

Since grapes are highly sensitive to impact due to their relatively thin skins, they must 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

3.29 m3/t (boxes) [11]
4.18 m3/t (cartons) [11]
4.00 – 4.25 m3/t (boxes) [14]
2.80 m3/t (10 kg cartons on pallets) [39]


The stowage factor depends very much on weight categories and the packaging units used.


Stowage space requirements

Cool, dry, good ventilation


Segregation

Marker pen, oil crayon


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).


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Risk factors and loss prevention

RF Temperature

Grapes 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 -1.5 – 0°C [1]
approx. 0°C [2]
1 – 4°C [3]
-1 – -0.5°C [5]
-1 – -0.5°C [6]
-1 – 0°C [11]
-0.5 – 0.5°C [14]
-1 – 0°C [39]


Since the storage or transport temperature may vary depending upon the variety, exact refrigeration instructions should be obtained from the consignor. Where the grapes have a high sugar content, temperatures may be maintained slightly below freezing. Grapes with a low sugar content, on the other hand, require temperatures above freezing.

In order to prevent or limit the extent of postharvest water loss and consequent reduction in quality, the cargo must be refrigerated as rapidly as possible. The temperature of the cargo on loading should not be > 5°C.

The cargo and holds/containers should be precooled prior to loading.

Chilling damage begins at hold temperatures of approx. -2°C and generally results in total loss of the cargo.


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RF Humidity/Moisture

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

Designation Humidity/water content Source
Relative humidity 90% [1]
85 – 90% [2]
90 – 95% [3]
90 – 95% [5]
90 – 95% [6]
85 – 90% [14]
90 – 95% [39]
Water content 76 – 88% [1]
Maximum equilibrium moisture content 90% [1]


If shriveling of the grapes is to be avoided, relative humidity should be approx. 90 – 95%. However, relative humidity ranges of 85 – 90% are recommended in order to avoid moistening of the packaging materials, such as wood wool, and consequent mold growth on the grapes.

The cargo must be protected from seawater, rain and condensation water as moistening of the cargo and packaging materials increases the risk of spoilage.

Shriveling and drying of the grapes may be avoided by packaging them in perforated polyethylene film inside the fruit crates.


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RF Ventilation

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

Recommended ventilation conditions:

According to [1]: circulating air, 60 – 80 circulations/hour with continuous supply of fresh air

According to [14]: circulating air, 40 – 60 circulations/hour with continuous supply of fresh air

The supply of fresh air is determined in accordance with the CO2 content of the hold air and should be adjusted such that the permissible CO2 content of 1.5 vol.% according to [1] or of 0.5 vol.% according to [14] is not exceeded.


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RF Biotic activity

Grapes 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 0.2 – 0.4 mg/kg*h [1]
Upper limit of permissible CO2 content 1.5 vol.% [1]

0.5 vol.% [14]
Ethylene evolution  
Active behavior Being nonclimacteric fruit, grapes produce very little ethylene. The rate of ethylene production is below 0.1 µl/kg*h [16].
Passive behavior Grapes display low ethylene sensitivity [16] (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 Grapes have a pleasant odor. Due to the sulfurous fungicidal chemicals present in the packaging, they have a slightly pungent odor.
Passive behavior Grapes are highly odor-sensitive.



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RF Contamination

Active behavior Grapes do not cause contamination.
Passive behavior The cargo is sensitive to dust, dirt, fats and oils. The holds or containers must accordingly be clean and in a thoroughly hygienic condition before loading.



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RF Mechanical influences

Since grapes are highly impact-sensitive, harvesting is entirely manual. Due to their sensitivity to mechanical influences, particularly high quality dessert grapes are packaged in cartons or fruit crates lined with wood wool in order to protect them from any injury and consequent premature spoilage during transport.


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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 2 – 3%.


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RF Insect infestation / Diseases

Gray mold rot: this rot is caused by the mold Botrytis cinerea and is thus also known as Botrytis rot. Affected grapes are covered by an initially white, then dark gray mold which produces large quantities of dust on contact. This mold can also move onto the stem. Affected grapes become hard and collapse inwards. This is one of the most dangerous diseases of grapes during storage and transport. Infestation may be extremely severe if the weather has been very wet before harvest. The mold also attacks completely healthy fruit. The mold grows best at 24°C, but is still capable of growing and causing rot even at a temperature of 0°C.

The disease is also known as sour rot (because the berries remain sour) or stem-end rot (as the berries often drop).

Photo, instance of damage

Figure 3
Photo, instance of damage

Figure 4
Photo, instance of damage

Figure 5
Photo, instance of damage

Figure 6
Photo, instance of damage

Figure 7


Figure 8


Dropping, i.e. berries dropping from the bunch, is not caused by microorganisms, but instead mainly occurs in late shipping. Batches suffering from dropping may often, and extremely rapidly, develop other diseases.

Dessert grapes are usually treated with sulfur dioxide (SO 2) in order to prevent mold growth.

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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