|
|
| (40 intermediate revisions by 2 users not shown) |
| Line 7: |
Line 7: |
| | | | |
| | | oil content = The oil content of barley is approx. 2%. | | | oil content = The oil content of barley is approx. 2%. |
| − | | ventilation = Recommended ventilation conditions: surface ventilation (see text). | + | | ventilation = Recommended ventilation conditions: surface ventilation (see text) |
| − | | risk factors = An excessively high water content may result in self-heating due to increased respiratory activity. | + | | risk factors = <ul><li>CO<sub>2</sub> Gases</li><li>Temperature; favorable travel temperature range: no lower limit - 20°C. Molds reach optimum activity at temperatures of between 20 and 30°C. In addition, at temperatures > 25°C, metabolic processes increase, leading to increased CO<sub>2</sub> production and self-heating of the barley</li><li>Self-heating / Spontaneous combustion</li><li>Odour</li><li>Contamination</li><li>Mechanical influences</li><li>Shrinkage/Shortage; evaporation may cause weight losses of at most 0.5%.</li><li>Insect infestation / Diseases</li></ul> |
| | }} | | }} |
| − | ==Description== | + | ==Description (See also [[Grain]])== |
| − | Barley is a type of cereal belonging to the grass family, the term "cereals" covering the [[grain]] fruits of cultivated grasses (spikes or ears in the case of [[wheat]], [[rye]], barley and [[corn]]; panicles in the case of [[oats]] and [[rice]].<br> | + | Barley is a common staple in human and animal diets. Part of the grass family, barley grows in over 100 countries and is one of the most popular cereal crops, surpassed only by [[wheat]], [[corn]] and rice. It is currently popular in temperate areas where it is grown as a summer crop and tropical areas where it is sown as a winter crop. Its germination time is one to three days. Barley grows under cool conditions, but is not particularly winter hardy. Barley has a short growing season and is also relatively drought tolerant<br><br> |
| − | Barley is not only grown in the summer, but also in the winter.
| |
| − | The structure and chemical composition of the [[grain]] vary little between the different types of cereal. <br><br>
| |
| − | | |
| − | It consists of three components: <br>
| |
| − | its cracked husk, the endosperm, which constitutes the main component of the grain and the embryo.<br><br>
| |
| − | | |
| − | After harvesting, barley usually undergoes further post-ripening, which consists of the high molecular weight substances congregating further with water being expelled. As the surface of the cereal then becomes damp because of the elevated water content, this is described as "sweating. In this state, the cereal is highly susceptible to mold and should not as yet be shipped. However, if the water content of the cereal is relatively low (approx. 13 - 14%), proper storage allows the sweat moisture to be absorbed by the air without the risk of mold growth. This sweating process proceeds for a period of approximately 1 - 2 months.<br><br>
| |
| − | | |
| − | Prior to loading, checks should be carried out and a certificate provided in relation to the moisture content, the absence of odor and contamination and the absence of pests.<br><br>
| |
| − | Excessively damp and incompletely ripened grain may be liable to self-heating, elevated respiratory activity, mold growth and fermentation during transport.<br>
| |
| − | The storage potential of barley which is "dry for shipment" may be up to 12 months or longer provided that the appropriate temperature, humidity/moisture and ventilation conditions are complied with.<br><br>
| |
| | | | |
| | ==Applications== | | ==Applications== |
| Line 28: |
Line 17: |
| | | | |
| | ==Shipping/storage== | | ==Shipping/storage== |
| − | Barley is chiefly transported as bulk cargo and only sometimes in bags (seed). <br><br> | + | Barley is chiefly transported as [[Bulk Cargo]] and only sometimes in bags (seed). <br><br> |
| | | | |
| − | <b>Grain size</b><br>
| |
| − | Diameter 1 mm, length 8 mm<br>
| |
| − | <br><br>
| |
| − | <b>Stowage space requirements</b><br>
| |
| − | Cool, dry, good ventilation. <br><br>
| |
| − |
| |
| − | ==Risk factors==
| |
| − | <b>Temperature</b><br>
| |
| − | Favorable travel temperature range: no lower limit - 20°C. Molds reach optimum activity at temperatures of between 20 and 30°C. In addition, at temperatures > 25°C, metabolic processes increase, leading to increased CO<sup>2</sup> production and self-heating of the barley.
| |
| − | <br><br>
| |
| | ==Humidity/Moisture== | | ==Humidity/Moisture== |
| − | Problems of moisture may be avoided by adequate pre-drying of the barley. This is the best way of reducing the activity (respiration) of the grain and removing the nutrient medium for mold growth and spoilage processes. The necessary level of dryness is approx. 11 - 14% water content, which is at equilibrium with relative humidity of up to 70% at 25°C. The mold growth threshold is reached at a water content of 15% (75% relative humidity). In cold transport regions, a relative humidity of 70% would be at equilibrium and the barley would not sustain any damage even at that level. At 16 - 17% water content, the sorption isotherm climbs sharply, implicating that equilibrium moisture contents of > 80% very rapidly produce an excessively damp atmosphere.<br><br>
| + | The best way of reducing the activity (respiration) of the [[grain]] and avoiding mold growth and spoilage processes is adequate pre-drying of the barley to approx. 11 - 14% moisture content.<br><br> |
| | | | |
| − | Individual clusters of damp product could initiate considerable damage to the cargo. The barley in such clusters has a tendency to self-heating. Damp (sweating) barley then appears in the boundary layers, so allowing the process to develop further. Such clusters may form, for example, in too freshly harvested product or where damp goods have been loaded.
| |
| − | <br><br>
| |
| − | Prior to loading, the loading moisture content should be checked by an independent inspector and a certificate provided.
| |
| − | <br><br>
| |
| | <b>Ventilation</b><br> | | <b>Ventilation</b><br> |
| − | Recommended ventilation conditions: surface ventilation. Ventilation of cereals depends on water content: goods with a water content of < 13% and equilibrium moisture contents of < 70% do not need to be ventilated.
| + | At < 13% moisture contents (and RH of < 70%) barley does not need to be ventilated. |
| − | <br><br>
| |
| − | Up to a water content of 15%, surface ventilation is recommended, such to dissipate CO<sub>2</sub>, heat and moisture. Concurrently, care should be taken to ensure that the surfaces are not cooled too much, to prevent the formation of damp boundary layers beneath the cargo surface.
| |
| − | <br><br>
| |
| − | Barley releases water vapor constantly, which needs to be dissipated by ventilation. However, caution is advisable on voyages from hot to cold regions (e.g. South America to N. Europe): Barley which is not dry for shipment has a particular tendency to self-heating and the flow of heat from the cargo counteracts external cooling, so resulting in the formation of steep temperature gradients in the superficial layers of the cargo. Concurrently, water vapor flows from the inside of the cargo to the surface. In the case of simultaneous cooling of the surface by ventilation, the relative humidity increases in the superficial layers of the cargo. If dry fresh air is used for ventilation, a dry surface layer several centimeters thick is obtained, which creates the impression that the cargo is free of all defects. Beneath this is then a damp intermediate layer of adverse cereal which is starting to decompose, coagulate and swollen.
| |
| − | <br><br>
| |
| − | In order to avoid cargo damage caused by such moist intermediate layers, the fresh air supply must be restricted when there is an excessive temperature differential between the cargo and the external temperature.
| |
| − | <br><br>
| |
| − | It is impossible to ensure proper airing throughout a bulk cargo of cereals. Even when ventilation is carried out, the relative humidity of the immobile air between the individual cereal grains is determined by the product's water content. For this reason, drying-out caused by ventilation is generally only superficial.
| |
| − | <br><br>
| |
| − | As a result, cereal loaded in an excessively moist state cannot be dried and protected from spoilage by a ship's ventilation installation.
| |
| − | <br><br>
| |
| − | <b>Biotic activity</b><br>
| |
| − | Barley displays 2nd order biotic activity. It is a living organ in which respiration processes predominate, because its supply of new nutrients has been cut off by separation from the parent plant.
| |
| − | <br><br>
| |
| − | <b>Gases</b><br>
| |
| − | In barley, metabolic processes continue even after harvesting. The cereal grains absorb oxygen and excrete carbon dioxide (CO<sub>2</sub>). This excretion of carbon dioxide is important from various standpoints. If relatively large quantities of CO<sub>2</sub> accumulate in the hold, the respiratory activity of the cereal will drop. In the case of cereal which is dry for shipment, hold or container air with an increased CO<sub>2</sub> content does not have a negative impact on the quality of the cargo, indeed mold growth is inhibited.<br>
| |
| − | However, if barley is shipped in closed holds/containers at relatively high water contents, the cereal must be expected to change over from aerobic to anaerobic respiration due to the build-up of CO<sub>2</sub>, which means, among other things, that lactic acid bacteria, which are able to tolerate an anaerobic environment, can also develop. Due to their toxicity, the resultant fermentation products CO<sub>2</sub>, lactic acid and alcohol have an impact on the grain germ, especially on seed cereal, which loses its ability to germinate if stored in an oxygen-depleted environment.
| |
| − | <br><br>
| |
| − | Respiration may cause life-threatening CO<sub>2</sub> concentrations (TLV: 0.49 vol.%) or O<sub>2</sub> shortages in the hold/container. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.
| |
| − | <br><br>
| |
| − | <b>Self-heating / Spontaneous combustion</b><br>
| |
| − | The oil content of barley is approx. 2%. An excessively high water content may result in self-heating due to increased respiratory activity. The barley in individual clusters of excessively moist cargo heats up and gives rise to more damp (sweating) cereal at the boundary layers of the cluster. In this way, the process propagates into other parts of the cargo. Such clusters may form, for example, in too freshly harvested product (not yet post-ripened) or where excessively damp goods have been loaded.
| |
| − | <br><br>
| |
| − | <b>Odor</b><br>
| |
| − | <i>Active behavior:</i> Barley has a slight, pleasant odor.<br>
| |
| − | <i>Passive behavior:</i> Barley is highly sensitive to the absorption of foreign odors.<br>
| |
| − | <br>
| |
| − | Gases and aroma substances, such as sulfur dioxide (SO<sub>2</sub>), phenol and kerosene, are readily absorbed by the cereal. For this reason, holds must be completely odor-free and deodorization must not be carried out only immediately before loading.
| |
| − | <br><br>
| |
| − | <b>Contamination</b><br>
| |
| − | <i>Active behavior:</i> Barley causes contamination by forming dust.<br>
| |
| − | <i>Passive behavior:</i> Especially after the carriage of contaminating ([[coal]], [[ores]], [[cement]]), odor-tainting or pest-infested cargoes, fitness for loading must be carefully reestablished by cleaning, disinfection, deodorization and ventilation. An inspection certificate confirming fitness for loading should be provided.
| |
| − | <br><br>
| |
| − | <b>Mechanical influences</b><br>
| |
| − | Suction and blowing devices may cause damage to the grains during cargo handling.
| |
| − | <br><br>
| |
| − | <b>Toxicity / Hazards to health</b><br>
| |
| − | Respiration may cause life-threatening CO<sub>2</sub> concentrations (TLV: 0.49 vol.%) or O<sub>2</sub> shortages in the hold/container. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.
| |
| − | <br><br>
| |
| − | <b>Shrinkage/Shortage</b><br>
| |
| − | Evaporation may cause weight losses of at most 0.5%. Further losses may arise due to dust formation and adhesion to the hold or container walls.
| |
| − | <br><br>
| |
| − | <b>Insect infestation / Diseases</b><br>
| |
| − | Barley may be infested by the following cereal pests during storage and transport:
| |
| − | <ul><li>by the granary weevil (Sitophilus granarius)</li><li>by the cadelle beetle (Tenebroides mauretanicus)</li><li>by the rust-red grain beetle (Cryptolestes ferrugineus)</li><li>by the sawtoothed grain beetle (Oryzaephilus surinamensis)</li><li>by the European grain moth (Nemapogon granellus)</li><li>by the Angoumois cereal moth (Sitotroga cerealella)</li></ul><br>
| |
| − | The chewing damage caused by the cereal pests brings about increased respiration in the cereal (hot spots) and this, associated with the metabolic activity of the pests themselves, promotes evolution of heat and moisture, which in turn provide favorable living conditions for molds and subsequently, at very high moisture levels, for bacterial growth.
| |
| − | <br><br>
| |
| − | Insect infestation may result in self-heating which ultimately gives rise to depreciation and finally total loss. Inadequately cleaned warehouses and holds/containers are generally the root cause of insect infestation. Cereal is also at risk from rats and mice, which can act as disease vectors and contaminate the cereal. Before loading, holds/containers should be examined by an independent inspector for infestation by pests of any kind and an appropriate certificate obtained.
| |
| | <br><br> | | <br><br> |
| | + | Up to moisture contents of 15%, adequate surface ventilation is advisable but not too cold to avoid damp superficial layers beneath the cargo surface. When there is a significant temperature gradient between the cargo and the external temperature, ventilation should be restricted.<br><br> |
| | + | Cereals loaded in a too moist condition cannot be protected from spoilage by ship's ventilation system.<br><br> |
| | + | |
| | Note: <i>(Source including Transport Information Service of the GDV)</i> | | Note: <i>(Source including Transport Information Service of the GDV)</i> |
| − |
| |
| | | | |
| | [[Category: Products]] | | [[Category: Products]] |
| | [[Category: Seeds and agriproducts]] | | [[Category: Seeds and agriproducts]] |
