RF Ventilation. Walnuts 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). RF Biotic activity. Walnuts display 2nd order biotic activity. They are living organs in which respiration processes predominate, because their supply of new nutrients has beencut 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. RF Gases. In walnuts (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.% RF Self-heating / Spontaneous combustion. Oil content: • 50 - 65% • 40 - 65% Because of their tendency to self-heating, walnuts may behave like substances from Class 4.2 of the IMDG Code. Heating damage occurs in particular in shipments from India, Chile and other tropical regions due to incorrect stacking before and during the voyage and results in rancidity of the nuts, which will subsequently at best be suitable for industrial processing. Walnuts should not be stowed together with fibers/fibrous materials as oil-soaked fibers may promote self-heating/ spontaneous combustion of the cargo. Fat decomposition in walnuts 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 walnuts 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 walnuts to form carbon dioxide and water, a process which is associated with considerable evolution of heat. Self-heating of walnuts 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 walnuts 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 walnuts with a high water content tend in particular towards rapid self-heating and may also ignite. Self-heating of walnuts 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 walnuts, 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 walnuts 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. RF Odor. Active behavior Walnuts have a very slight, pleasant odor. Passive behavior Walnuts are sensitive to unpleasant and/or pungent odors. They should be stored and transported in clean air away from foodstuffs with an intense odor. RF Contamination. Active behavior Risk of contamination of other goods by fats and oils. Passive behavior Walnuts are sensitive to dust, dirt, fats and oils. RF Mechanical influences. Walnuts are impact- and pressure-sensitive. If stack pressure is too high, the walnuts are crushed, so promoting self-heating. In addition, if the nuts are transported in jute bags, the oils accumulate in the fabric and accelerate the process. 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.%. Danger: walnuts may contain aflatoxin. 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 walnuts at the time of harvesting. As a rule, aflatoxin is only found in individual walnuts. If batches intended as a human foodstuff are affected by this toxin, the product can no longer be approved for human consumption. Walnuts affected by aflatoxin cannot readily be distinguished from the other nuts in a batch. The toxin may be detected using UV light. RF Shrinkage/Shortage. Weight loss of up to 2% due to moisture loss is tolerated. Loss of volume may be caused by tears in bags and by theft. The risk is increased by repeated cargo handling and extended storage. RF Insect infestation / Diseases. On acceptance, attention must be paid to inspecting the cargo for insect infestation. The time of infestation may be determined with some certainty by the stage of development of the pests, with infestation generally occurring in the country of origin. The proportion of empty, bad or pest-infested walnuts should not exceed 15%. Mites, cockroaches, sawtoothed grain beetles, flour beetles, meal moths, dried fruit moths and rats and mice may attack walnuts. Walnuts 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. http://www.tis-gdv.de/

Product Information