Cashew nuts, cashew kernels [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 Cashewnüsse (Kaschunüsse), Cashewkerne
English Cashew nuts, cashew kernels
French Noix de cajou, Noix d'arabie
Spanish Anacardos
Scientific Anacardium occidentale
CN/HS number * 0801 30 ff.


(* EU Combined Nomenclature/Harmonized System)



Product description

Cashew nuts are the stone fruits of the cashew tree, which grows to a height of up to 12 m and belongs to the sumach family (Anacardiaceae).

Cashew nuts are shell fruit (nut types). Because of their similar characteristics with regard to transport, particularly their high oil content, their requirements regarding care during storage and transport are the same as those of oil-bearing seeds/fruits.

Cashew nuts are classed as follows:

1. Cashew apple

The cashew apple, at up to 9 cm in length, is the pear-shaped, swollen, soft, shiny yellow or red, fleshy stem of the cashew nut proper. The cashew apple itself is not suitable for transport and storage.

2. The cashew nut

The cashew nut is a stone fruit, which grows out of the bottom of the cashew apple, is approx. 2 - 2.5 cm long, kidney-shaped, yellowish-reddish in color and has a hard shell with a single kernel with a delicate aroma. It is removed from the cashew apple after harvesting and sun- or hot air-dried, the shell then becoming detached to reveal the kernel proper.

3. The cashew kernel

This is surrounded by a fine, brown seed coat, which contains antioxidants which protect the kernel from penetration by atmospheric oxygen so preventing it from becoming rancid (oxidative rancidity).

Cashew nuts are also known as anacardium nuts.

Oil content: 45 - 50%


Quality / Duration of storage

There are two commercial grades of cashew nut: "white" and "scorched" (i.e. discolored), the latter arising as a result of overheating during the drying process.

The shell contains a high proportion of toxic CNSL (Cashew Nut Shell Liquid), which is used in the paints and brake lining industries and acts as a protective jacket giving the raw product a storage life measured in years [2].

It is very important for the surveyor to ascertain the year of harvest: it must be taken into consideration that the nuts may be mixed with nuts from the previous year's harvest. This possibility must not be disregarded when determining whether or not loss has occurred in transit. Nuts from the previous year's harvest have a tendency to beetle infestation and rancidity.


Intended use

Mainly eaten raw and used in muesli, salads, desserts, vegetable and meat dishes and in trail mixes.

Jam is made from the light yellow, juicy, sharp, fruity-tasting flesh of the cashew apple. In the countries where the cashew apple grows, it is also used in the drinks industry.


Figures

(Click on the individual Figures to enlarge them.)

Drawing, cashew nuts)

Figure 1
Photo, cashew nuts

Figure 2
Photo, cashew nuts

Figure 3



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  
Africa Mozambique, Tanzania, Kenya, Egypt
Asia India, China
America Mexico, West Indies
Australia  


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Packaging

Cashew kernels are packaged in boxes or cartons containing two sealed tinplate canisters to protect the product from autoxidation.

Cashew nuts are packaged in, among other things, polysacks (10 - 25 kg).


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Transport

Symbols

Symbol, general cargo

General cargo


Temperature-controlled



Means of transport

Ship, truck, railroad


Container transport

Ventilated containers (coffee containers), if the lower limits set for the water content of goods, packaging and flooring and the oil content of the goods are complied with and if protection against solar radiation is ensured (risk of self-heating). Cashew kernels are predominantly shipped in containers.


Cargo handling

In damp weather (rain, snow), the cargo must be protected from moisture, since it may lead to mold, spoilage and self-heating as a result of increased respiratory activity.

No hooks should be used with bagged cargo, so as to prevent damage to the bags and loss of volume.


Stowage factor

2.00 m3/t (wooden boxes, 54 kg) [1]
2.12 - 2.27 m3/t (bags) [14]
1.55 - 1.70 m3/t (boxes) [14]


Stowage space requirements

Cool, dry, good ventilation. Do not stow near heat sources.


Segregation

Marker pen, oil crayon


Cargo securing

In order to ensure safe transport, the bags must be stowed and secured in the means of transport in such a manner that they cannot slip or shift during transport. Attention must also be paid to stowage patterns which may be required as a result of special considerations, such as ventilation measures.

In the event of loading as general cargo, dunnage should be used to protect against damage:

Floor dunnage: criss-cross dunnage and packing paper
Side dunnage: lining with wooden dunnage and mats or jute coverings: protection from metal parts of the ship, since traces of metal promote cargo rancidity due to autoxidation.
Top dunnage: important for voyages to cold regions (winter), since sweat may drip onto the cargo.



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Risk factors and loss prevention

RF Temperature

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

Favorable travel temperature range: 5 - 25°C [1]

Temperatures > 30°C should not prevail for a long period, as such temperatures promote respiration of the cargo and cause self-heating. Daily temperature measurements should be taken and the results recorded.


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RF Humidity/Moisture

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

Designation Humidity/water content Source
Relative humidity 70% [1]
Water content 5.0 - 6.0% [1]
4.5 - 5.0% [48]
Maximum equilibrium moisture content 65% [1]


Cashew nuts in bags are at risk of moisture penetration and mold formation due to ship/container sweat. The goods may cake, turn rancid and discolor. Soaked cartons may also discolor and lose strength, and jerricans may corrode.

On the other hand, excessive dryness may lead to breakage.

During lighterage, care must be taken to avoid seawater damage (Silver nitrate method).

In the Tropics, sudden, heavy downpours occurring during cargo handling may damage the cargo.

When container transport is used, damage due to moisture may arise if the water content of the cargo is too high or if defects in the containers allow water to penetrate. The lack of ventilation in 90% full standard containers may cause spoilage.


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RF Ventilation

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

Recommended ventilation conditions: air exchange rate at least 10 changes/hour (airing)

The heat arising due to the self-heating process must be dissipated as quickly as possible by ventilation, since hot spots spread very rapidly and may affect entire batches of cargo.

It is advisable to stow so as to leave trenches, so that water vapor and heat may be removed by suitable ventilation measures.


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RF Biotic activity

Cashew nuts 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 keeping decomposition processes at the lowest possible level, so as to keep within limits any losses in quality caused by the emission of CO2, heat and water vapor.


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RF Gases

In cashew nuts/kernels (particularly when fresh), metabolic processes continue even after harvesting. They absorb oxygen and excrete carbon dioxide (CO2).

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

A high cargo oil content of 45 - 50% encourages the risk of self-heating or rancidity.

Because of this tendency to self-heating/spontaneous combustion, cashew nuts/kernels may behave like substances from Class 4.2 of the IMDG Code. See also IMO Code of Safe Practice for Solid Bulk Cargoes.

Fat decomposition in cashew nuts leads to the risk of self-heating and, ultimately, to a cargo fire.

Fat decomposition may proceed as follows:

by hydrolytic/enzymatic fat cleavage or
by oxidative fat cleavage


Hydrolytic/enzymatic fat cleavage:

If the critical water content of the cashew nuts is exceeded, this promotes hydrolytic/enzymatic fat cleavage. Fat-cleaving enzymes are activated by the elevated water content. The additional action of light and heat may accelerate this process. Free fatty acids sometimes have an unpleasant odor and taste. In the event of extended storage or improper cargo care, these cause the cargo to become rancid.

The free fatty acids formed are consumed by respiration processes in the cashew nuts to form carbon dioxide and water, a process which is associated with considerable evolution of heat.

Self-heating of cashew nuts is an extremely vigorous process, as the consumption of fatty acids by respiration processes is associated with a considerably greater evolution of heat than is the case with the respiration equation for carbohydrates. Here too, as with cereals, the spoilage process proceeds in a type of chain reaction, because heat and water are formed by the fatty acids consumed by respiration, which in turn contribute to an intensification of the process.

The self-heating of cashew nuts requires only a small seat of moisture, so that within just a few hours heating may occur at moist points for which weeks or months would be required in goods dry on shipment.

Fresh cashew nuts with a high water content tend in particular towards rapid self-heating and may also ignite. Self-heating of cashew nuts leads not only to a reduction in the utility value of this product (rancid odor and taste) but also has a qualitative and quantitative effect on oil yield. The color and bleachability of the oils are also negatively affected. The oil obtained complicates refining of the crude oils in subsequent processing, because a higher free fatty acid content makes decolorization substantially more difficult.

Hydrolytic/enzymatic fat cleavage and respiration may be limited by low temperatures; however, this may only be affected to a limited degree during transport. It is therefore important to ensure storage stability by complying with the limit values for the water content of the goods.


Oxidative fat cleavage:

Food components frequently react with atmospheric oxygen in spoilage processes. Atmospheric oxygen may enter into an addition reaction with unsaturated fatty acids through the simultaneous assistance of light, heat and certain fat companion substances, and possibly also traces of heavy metals. Rancidity caused by oxidative fat cleavage is particularly noticeable in the case of shelled cashew nuts, because the shelling process results to a certain degree in exposure to atmospheric oxygen or to the steel parts of the ship or the container walls, if not carefully covered. It is therefore absolutely essential to store cashew nuts in the dark and to protect them from oxygen and metal parts, since otherwise they become brown-colored and develop a rancid odor and taste.


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RF Odor

Active behavior Cashew nuts do not release any odor.
Passive behavior Cashew nuts are sensitive to unpleasant and/or pungent odors.



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RF Contamination

Active behavior The high oil content of the goods frequently causes dark fat stains to appear on the bags, which must therefore be kept from coming into contact with goods sensitive to contamination, such as baled goods, tea chests, marble etc..

Cashew nuts in bags must not be stowed together with fibers or fibrous materials, either, since oil-impregnated fibers accelerate self-heating processes.

Cashew nuts often also contain a high proportion of fine dust or sand.
Passive behavior Cashew nuts are 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

Cashew nuts are impact- and pressure-sensitive. The cashew nuts/kernels may suffer breakage.


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RF Toxicity / Hazards to health

Respiration may cause life-threatening CO2 concentrations (TLV: 0.49 vol.%) or O2 shortages in the hold/container. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.

Danger: cashew nuts may contain aflatoxin. They are therefore tested for aflatoxins prior to export and in the importing countries, as these develop particularly frequently as a result of improper harvesting and storage.

The molds Aspergillus flavus and Aspergillus parasiticus produce the toxin aflatoxin, which may be present in the cargo as a result of an attack by the above-mentioned mold types (see risk factors Humidity/Moisture and Ventilation). In general, this is "country damage", i.e. the toxin is already present in the cashew nut at the time of harvesting. As a rule, aflatoxin is only found in individual nuts. If batches intended as a human foodstuff are affected by this toxin, the product can no longer be approved for human consumption. Nuts affected by aflatoxin cannot readily be distinguished from the other nuts in a batch. The toxin may be detected using UV light.


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RF Shrinkage/Shortage

In the case of conventional loading, volume is generally lost only as a result of tears in bags.

Valuable cargo, so at high risk of theft.


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RF Insect infestation / Diseases

Mites, cockroaches, sawtoothed grain beetles, flour beetles, meal moths, dried fruit moths and rats and mice may attack nuts and thus also cashew nuts/kernels. Nuts from the previous year's harvest have a particular tendency to beetle infestation.

The quarantine regulations of the country of destination must be complied with and a phytosanitary certificate and fumigation 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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