Moist Grain Research Articles

PRACTICAL QUESTIONS FOR SILO BAGS GRAIN STORAGE TECHNOLOGY

In enterprises with limited capacities and a low-powered grain drying facilities there is a problem of economical and reliable storage of dry, wet and moist grains. One of the options for its successful solution is the application of grain storage technology in silo bags, tested in many enterprises, the basic principle of which is based on the self-preservation of grain under hermetic conditions in an environment of carbon dioxide. To implement this technology, it is necessary to determine the suitability of the batch of grain for loading in the silo bags on the basis of an operational analysis of the grain quality. After loading the grain, the silo bags are sealed, the grain mass is stored for a certain time and then unloaded. After many years of industrial testing of grain storage technology in silobags, recommendations have been developed that allow to ensure the quantity and proper quality of grain in the process of implementation of the technology. To do this, it is provided to carry out a whole range of activities - personnel training, the selection and preparation of a storage area for grain, deratization, the determination of the quality of grain at all stages and a safe shelf-life, depending on the condition of the grain, weighing of the grain; loading silo bags and placing them on the site; drawing of marks for identification of silobags; monitoring of the state of silo bags and grain and the restoration of the integrity of the silo bags throughout the storage period; accounting for grain in the silobags; processing of unconditioned grain; object protection, final analysis of the work performed, identify problems and ways to solve them. The storage site for grain in the silo bags must be cleaned of stubble and grass, sharp objects, grain residues, solid hardwood or the most densely packed soil (the clay surface is undesirable, as precipitation makes imposible laying and unloading of silobags), ensure no stagnation of water during rains and melting snow, provide the possibility of free movement of special equipment on the site. It must be deratized and fenced with a mesh with small openings, a height of at least 1 m and dipped. The analysis of the characteristics of three-layer silobags showed that to optimize the storage of dry grain, it is advisable to use the largest silobags of 90 m in length, since they have a larger capacity, there will be less time spent on dressing and sealing the silobags, saving space between the silo bags lying along one another , there will be less length of silobags to go for tying, as well as saving money on the cost of silobags, the cost of working time and fuel (decreases the number of transfers of special equipment). It is advisable to take into account the possibility of unloading the sleeve during one shift. At all stages (loading, storage, unloading) the determination of the quality of grain, monitoring the condition and restoring the integrity of the silo bags checking the sanitary condition of the site and the presence of baits should be carried out. Precautions should be observed, grain accounting, working with non-standard grain and final analysis of grain storage results should be carried out.

Kuivatun viljan varastoinnin maa

Tuoreen ja kostean viljan varastoiminen on aina ollut haasteellista, sillä se pilaantuu helposti. Jos nykyäänkin viljaa halutaan varastoida pitkäaikaisesti, viljan kosteus pitää saada riittävän alhaiseksi. Kuivauksen tarve riippui siitä, kuinka kuivaa vilja on korjattaessa ja miten kuivaksi se voitiin saada pelkästään ulkokuivauksella. Pohjoisissa olosuhteissa ulkokuivaus on haasteellista, minkä vuoksi Suomessa, Baltiassa ja Venäjällä vilja on pyritty kuivaamaan keinotekoisesti riihien avulla jo vuosisatojen ajan. Riihet olivat rakenteeltaan yksinkertaisia hirsirakennuksia, joiden sisällä oli uuni ja parret. Riihen lämmittäminen vaati paljon polttopuuta ja käyttäjiltään taitoa, mitkä tekijät osaltaan rajoittivat tekniikan leviämistä. Vaikka riihikuivauksen tekniikka on ollut pitkään tunnettu, sen laajempaa merkitystä ei tästä huolimatta ole tutkimuksissa juuri käsitelty.
 Tässä artikkelissa riihikuivausta tarkastellaan kuivatun viljan ja sen varastoinnin näkökulmasta. Ruotsin valtakunnassa kuivattua viljaa hankittiin suuret määrät kruununmakasiineihin, joihin tarvittiin varmuusvarastoja sekä sotien että katojen varalle. Tutkimuksen on selvitetty, miksi varastoon hankittiin nimenomaan riihikuivattua viljaa ja miten paljon sitä määrällisesti oli makasiineissa. Tutkimusajanjaksona on hattujen sodan ja Pommerin sodan välinen rauhan aika (1743–1757). Maantieteellisesti tutkimus kattaa Pommeria lukuun ottamatta koko Ruotsin valtakunnan eli nykyiset Suomen ja Ruotsin alueet.
 Tutkimuksesta käy ilmi, että suurin osa Ruotsin valtakunnan kruununmakasiineissa olleesta viljasta oli tutkimusajanjaksolla riihikuivattua. Selvimmin tämä näkyi Suomen makasiineissa, joissa oli vain riihikuivattua ruista lukuun ottamatta Ruotsista vuonna 1750 tuotua viljaa. Vaikeudet tämän tuontiviljan varastoimisessa ja hyödyntämisessä osoittavat sen, miten tottumattomia Suomessa oltiin kuivaamattomaan viljan käyttöön. Myös Ruotsin puolella valtakuntaa keskeisimmissä varastoissa, Tukholmassa ja Karlskronassa, pääosa viljasta oli riihikuivattua. Koska Ruotsissa riihikuivausta ei juuri harjoitettu, vilja piti hankkia varastoihin muualta. Riihikuivattua viljaa saatiin Suomesta sekä veroina että ostoina. Erityisesti Pohjanmaalta tuotua laadukasta Vaasan ruista arvostettiin Ruotsissa. Suurin osa Tukholman makasiineihin tuodusta riihikuivatusta viljasta oli kuitenkin peräisin ilmeisesti Baltiasta. Kuivatun viljan varmuusvarastoinnille oli Ruotsin valtakunnassa 1700-luvulla tarvetta, sillä valtakunta oli riippuvainen viljan tuonnista. Usein toistuneet kadot ja sodankäynnin tarpeet edellyttivät, että varastoissa oli jatkuvasti viljaa pahimman varalle.

Starch: Granule, Amylose-Amylopectin, Feed Preparation, and Recovery by the Fowl's Gastrointestinal Tract

SUMMARY Starch exists as glucose polymers of amylose and amylopectin. Amylose involves 10–30 glucose units having α-1,4-linkages enabling self-association into a helix. Amylopectin is assembled from a large number of helices interconnected by α-1,6-branching to dominate each granule. Granules have amorphous branching alternate with layers of crystallized helices. Crystallization involves helices laterally held together with either intermediary water (A) or is direct H-bonded (B) to resist digestion. Granule digestion by α-amylase depends on attachment along the helix length with release of maltose and maltotriose which includes α-limit dextrins from amylopectin. Amyloplasts progressively assemble each granule with sequential cell filling from aleurone to core during endosperm maturation. Incomplete development reduces endosperm starch content and energy value while losses from germination are less influential. High temperature drying of moist grain creates resistant granules due to annealing and partial loss of bound water from A- to form H-bonding and B-crystals. Further annealing and additional resistance occurs with high temperature pelleting. Extrusion extends annealing together with granule gelatinization which frees polymers enabling retrogradion into resistant crystallites of amylose while amylopectin remains amorphous and digestible. Pellet stability reduces feed loss and work of prehension. Gastric digestion improves granule exposure. Pancreatic α-amylase erodes granules within the small intestine with products transferring to the unstirred water layer where microvilli enzymes generate glucose for absorption. Resistance delays granule erosion with potential continuance and fermentation in the large intestine that reduces NE then AME if excreted. Starch resistance influences location of digestion by the gastrointestinal tract and product use.

Fermentation quality and aerobic stability of low moisture-crimped wheat grains manipulated by organic acid-based additives

AbstractPreservation of moist grain anaerobically by so-called crimping has many advantages. Generally, preservation has been successfully performed when grain is harvested at 30–40% moisture content (MC). However, there is a trend towards using drier than the optimal MC of the raw material. This leads to an increasing need to control aerobic spoilage of the material and also to experimental challenges in assessing the quality and stability of low-MC crimped grain. The objective of the current work was to evaluate fermentation quality, microbial composition and aerobic stability (AS) of drier than the optimal crimped grain ensiled with different additives and to use these materials to compare three different AS evaluation methods. Crimped wheat grain with 28% MC was ensiled using eight additive treatments based mainly on formic and propionic acids including a control without any additive. The low MC resulted in no lactic acid fermentation, but significant ethanol formation occurred in the control. The treatments used resulted in clear differences in microbial quality and AS of the feeds, and use of formic and propionic acid-based additives provided a clear benefit in improving the AS of crimped wheat grain. The correlation between increasing temperature and carbon dioxide (CO2) production under aerobic conditions was very close, indicating that CO2produced by aerobic bacteria can be used as a method of evaluating AS. Visual inspection of mould growth resulted in somewhat different ranking of the treatments.

Maize Grain Stored in Hermetic Bags: Effect of Moisture and Pest Infestation on Grain Quality

Maize (Zea mays) is an important staple food crop produced by the majority of smallholder farmers that provides household food security through direct consumption and income generation. However, postharvest grain losses caused by insect pests during storage pose a major constraint to household food security. Hermetic storage technology is an alternative method that minimises postharvest losses by depleting oxygen and increasing carbon dioxide levels within the storage container through metabolic respiration of the grains, insects, and microorganism. Maize grain was stored for 180 days in hermetic bags or open-weave polypropylene bags to compare quality preservation when subject to initial grain moisture contents of 12, 14, 16, and 18 percent and infestation by Sitophilus zeamais. The moisture content of grain in hermetic bags remained unchanged while in polypropylene bags decreased. Dry grains (12% moisture content) stored well in hermetic bags and suffered 1.2% weight loss while for equivalent grains in polypropylene bags the weight loss was 35.8%. Moist grains (18% moisture content) recorded the lowest insect density (7 adults/kg grain) in hermetic bags while polypropylene bags had the highest (1273 adults/kg grain). Hermetic and polypropylene bags recorded the lowest (0–4 adults/kg grain) and highest (16–41 adults/kg grain) Prostephanus truncatus population, respectively. Discoloured grains were 4, 6, and 12 times more in grains at 14, 16, and 18 than 12 percent moisture content in hermetic bags. Grains at 18% moisture content recorded significantly lower oxygen (10.2%) and higher carbon dioxide (18.9%) levels. Holes made by P. truncatus in the hermetic bags were observed. In conclusion, storage of moist grains (14–18% moisture content) in hermetic bags may pose health risk due to grain discolouration caused by fungal growth that produces mycotoxins if the grains enter the food chain. The study was on only one site which was hot and dry and further investigation under cool, hot, and humid conditions is required.

Combined moist airtight storage and feed fermentation of barley by the yeast Wickerhamomyces anomalus and a lactic acid bacteria consortium.

This study combined moist airtight storage of moist grain with pig feed fermentation. Starter cultures with the potential to facilitate both technologies were added to airtight stored moist crimped cereal grain, and the impact on storage microflora and the quality of feed fermentations generated from the grain was investigated. Four treatments were compared: three based on moist barley, either un-inoculated (M), inoculated with Wickerhamomyces anomalus (W), or inoculated with W. anomalus and LAB starter culture, containing Pediococcus acidilactici DSM 16243, Pediococcus pentosaceus DSM 12834 and Lactobacillus plantarum DSM 12837 (WLAB); and one treatment based on dried barley (D). After 6 weeks of storage, four feed fermentations FM, FW, FWLAB, and FD, were initiated from M, W, WLAB, and D, respectively, by mixing the grain with water to a dry matter content of 30%. Each treatment was fermented in batch initially for 7 days and then kept in a continuous mode by adding new feed daily with 50% back-slop. During the 6 week storage period, the average water activity decreased in M, W and WLAB from 0.96 to 0.85, and cereal pH decreased from approximately 6.0 at harvest to 4.5. Feed fermentation conferred a further pH decrease to 3.8–4.1. In M, W and WLAB, molds and Enterobacteriaceae were mostly below detection limit, whereas both organism groups were detected in D. In fermented feed, Enterobacteriaceae were below detection limit in almost all conditions. Molds were detected in FD, for most of the fermentation time in FM and at some sampling points in FW and FWLAB. Starter organisms, especially W. anomalus and L. plantarum comprised a considerable proportion of the yeast and LAB populations, respectively, in both stored grain and fermented feed. However, autochthonous Pichia kudriavzevii and Kazachstania exigua partially dominated the yeast populations in stored grain and fermented feed, respectively.

The impact of moist corn grain preservation on the ethanol yield by simultaneous saccharification and fermentation, and on volatile by-products

We assessed the composition of volatile by-products in raw spirits obtained from moist corn fermentation. The average moisture value of the researched samples was 35.4%. A comparative research was conducted applying simultaneous saccharification and fermentation (SSF) process with Saccharomyces cerevisiae. The analysis characterised corn grains after three and six months of storage in aerobic and anaerobic conditions. The yield of ethanol fermentation was 42.43 and 39.12 l/100 kg dry matter after three and six months of storage, respectively. The storage of moist grain resulted in the reduction of higher alcohols content in the raw spirits. It was observed that the esters concentration decreased after three, but increased after six months of raw material storage. A significant increase occurred in the quantity of aldehydes detected only after three months of the corn storage. The results show that the application of SSF technology to moist corn, allows the production of bioethanol with quality comparable to that obtained with dried grain.  

The dynamics of physical properties, seed moisture content, market economics and post harvest management of six bean varieties (Phaseolus vulgaris) grown in the sub Saharan region in Africa

Managing grain moisture content is important because maximum economic return can be achieved by marketing at a certain moisture level of grain. Post-harvest management dictates that grains must be dried to certain levels to avoid development of fungal and insect problems, respiration and germination. However, over drying can also a lead to economic losses. Most farmers are aware of fungal development in moist grains but few are aware that they make less profit by over drying. Moreover, there are also bean varieties which genetically retain more water than others and hence can be safer and have more economic returns compared to others. But, this also should be matched to the rain pattern in a growing region. We compared six varieties of beans (KAT B1, KAT B9, and Kakunzu (KKZ), Rose Coco (GLP2/RCC), Kenya Tamu and KAT X56) grown in the South Eastern region of Kenya and found significant differences in dry moisture content, physical properties and grain weights. The Rose Coco and KAT X56 varieties had the highest moisture content retention but the KKZ variety the lowest. This explained why KKZ is favoured more by famers in arid areas with less rain during fruit maturation.

Equisetumarvense hydro‐alcoholic extract: phenolic composition and antifungal and antimycotoxigenic effect against Aspergillusflavus and Fusariumverticillioides in stored maize

Maize is a very important cereal for human and animal diet, but it can be contaminated by moulds and their mycotoxins. On the other hand, natural plant products with antimicrobial properties could possibly used to control mycotoxigenic fungi in foods and feeds. In this study, Equisetum arvense extract was tested for the efficacy on Aspergillus section Flavi and Fusarium section Liseola growth. Natural contaminated maize was used in this study and extract was added under different water activities (a(w)) - 0.90 and 0.95 - for Aspergillus section Flavi and Fusarium section Liseola, respectively. Moulds were inoculated in maize and incubated during 30 days. We confirm that E. arvense extract may be effective for the inhibition of Aspergillus section Flavi in maize with high levels of this mould. Moreover, this extract showed a good inhibition of growth on Fusarium section Liseola levels. Aflatoxin and fumonisin production was not affected by the extract. E. arvense extract could be an alternative to synthetic fungicides to control maize mycobiota level in moist grain.

Estratégias de aeração de milho armazenado: temperatura e teor de água

O objetivo deste trabalho consistiu em avaliar e comparar o desempenho de três diferentes estratégias de aeração de milho armazenado: aeração contínua, aeração noturna e aeração em condições de equilíbrio higroscópico entre os grãos e o ar ambiente. Utilizaram-se grãos de milho com dois níveis de teor de água; 11% e 17%. Realizou-se monitoramento contínuo da temperatura, e amostras de grãos foram retiradas durante os ensaios para análise do teor de água. Observou-se que todas as estratégias de aeração favoreceram a redução da temperatura nos grãos secos (11%) e umidificados (17%). A estratégia de aeração contínua foi a mais eficiente em grãos úmidos, uma vez que evitou aquecimento dos grãos durante o armazenamento. Nenhuma estratégia de aeração manteve a temperatura homogênea no interior dos grãos durante a armazenagem. Ela variou conforme as condições climáticas. O teor de água dos grãos sofreu variações durante os ensaios, com tendência de secagem ao final do processo.

Pichia anomala yeast improves feed hygiene during storage of moist crimped barley grain under Swedish farm conditions

Preservation of moist crimped cereal grain is made feasible through fermentation by lactic acid bacteria. Climatic variations make it difficult to harvest at moisture contents (0.30–0.45 g/g) to support optimal fermentation under practical conditions. Therefore, the yeast, Pichia anomala J121, previously found to prevent mould spoilage and improve preservation of moist grain in malfunctioning airtight silos, was added to moist crimped cereal grain stored in large plastic tubes. Freshly harvested barley grain was crimped and inoculated with P. anomala (10 5 colony-forming units/g grain). Due to the local weather conditions, harvest was delayed and moisture content in the cereal grain had decreased to 0.16–0.18 g/g. P. anomala was inoculated into three batches of barley, each comprising 16 tonnes packed into large plastic tubes. Three additional sets of plastic tubes were packed with cereal grain without addition of P. anomala. The grain tubes were left closed for 5 months, after which feeding to cattle commenced. In both the P. anomala inoculated and the control barley, the population diversity of lactic acid bacteria (LAB) was very high over the duration of storage. However, the dominant LAB shifted over the course of storage to Pediococcus pentosaceus and Lactobacillus paracasei, in inoculated and control barley, respectively. The yeast population in the inoculated barley was totally dominated by P. anomala during the entire storage period. In the control grain, the yeast population was more diverse, displaying shifts in the dominant species during storage. Pichia burtonii was the dominant species at the last sampling occasion. In P. anomala inoculated barley, numbers of naturally occurring moulds were reduced by about two log units, and the number of Enterobacteriaceae was reduced to below detection.

Evaluation of different corn textures in dry grain or silage forms for piglets from 7 to 15 kg

The objective of this study was to evaluate different textures and storage forms of corn in piglet diets. Two experiments were conducted, one of which tested digestibility of nutrients and the other diet performance. In the digestibility trial, 24 crossbred (Landrace X Large White) barrows with an initial weight of 18.7 ± 1.5 kg were used. They were kept in metabolic cages in a randomized block design using the factorial arrangement 2 X 2 (type of corn - dent and flint X type of storage - moist grain silage and dry grain) and six replicates, with one animal as the experimental unit. The values of metabolizable energy (ME) obtained were 3841 kcal of ME/kg of dry matter (DM) from dry corn, 3912 kcal of ME/kg of DM from moist corn, 4022 kcal of DM from ensiled dry corn and 3928 kcal of ME/kg of DM from ensiled humidity corn. The ensilage process increases the digestibility coefficient of dry matter and crude protein and increases the digestible energy of the diets, independent of the process form. The type of corn did not influence these variables. In the performance trial, 60 barrows (initial weight of 6.5 ± 1.5 kg) of the same stock were used during 28 days of post-weaning distributed in the same experimental design, with five replicates and three animals as the experimental unit. The treatments did not influence the daily weigh gain or the daily feed intake. The dentate corn and the ensilage process decreased the feed conversion of the independent form (no significant interaction). The substitution of dry for ensilage corn increased the digestibility of the nutrients in the diets and the feed conversion of the piglets from 7 to 15 kg. Dentate corn promotes best feed conversion in this phase.

Airtight storage of moist wheat grain improves bioethanol yields

BackgroundDrying is currently the most frequently used conservation method for cereal grain, which in temperate climates consumes a major part of process energy. Airtight storage of moist feed grain using the biocontrol yeast Pichia anomala as biopreservation agent can substantially reduce the process energy for grain storage. In this study we tested the potential of moist stored grain for bioethanol production.ResultsThe ethanol yield from moist wheat was enhanced by 14% compared with the control obtained from traditionally (dry) stored grain. This enhancement was observed independently of whether or not P. anomala was added to the storage system, indicating that P. anomala does not impair ethanol fermentation. Starch and sugar analyses showed that during pre-treatment the starch of moist grain was better degraded by amylase treatment than that of the dry grain. Additional pre-treatment with cellulose and hemicellulose-degrading enzymes did not further increase the total ethanol yield. Sugar analysis after this pre-treatment showed an increased release of sugars not fermentable by Saccharomyces cerevisiae.ConclusionThe ethanol yield from wheat grain is increased by airtight storage of moist grain, which in addition can save substantial amounts of energy used for drying the grain. This provides a new opportunity to increase the sustainability of bioethanol production.

Simultaneous Monitoring of Stored Grain with Relative Humidity, Temperature, and Carbon Dioxide Sensors

Grain moisture content (MC) and temperature (T) are the primary factors affecting grain deterioration in storage. If these factors are not properly monitored and controlled, grain quality can deteriorate quickly due to mold growth and insect infestation. This research examined use of relative humidity (RH), T, and carbon dioxide (CO2) sensors for their suitability to determine adverse storage conditions of wheat. A mock-up storage system was constructed and used to simulate a wheat storage bin 6.86 m high. Sensors for T, RH, and CO2 measurement were placed at various depths in the storage. High-moisture grain, comprising about 11% of the grain volume, was placed in the top section of the bin. Wheat was aerated with the high-moisture grain conditioned to nominal MCs of 14%, 16%, and 18% wet basis (MCwb) and the remaining grain at approximately 11% MCwb. Sensors monitored air conditions during the entire storage period. Aeration was provided over 3-h periods at rates of 0.083 m3/min/tonne (eight experiments) and 0.166 m3/min/tonne (one experiment). Airflow was from top to bottom of the bin. CO2 sensors were effective in indirectly detecting moist grain conditions due to the large amount of CO2 generated from the wet grain. CO2 measurement was less effective as grain temperature was reduced as a result of aeration. CO2 levels monitored at the exhaust of the aeration duct were generally adequate in determining adverse storage conditions. The equilibrium moisture content (EMC) of wheat, determined from RH and T, gave reasonably accurate measurements of grain MC. EMC measurements were also effective in determining moisture changes in the grain due to the moisture front movement from the high-moisture grain.

Physiological manipulation and formulation of the biocontrol yeast Pichia anomala for control of Penicillium verrucosum and ochratoxin A contamination of moist grain

The major hurdle in the production of commercial biocontrol agents (BCAs) has been the lack of production of appropriate formulations. Of particular importance is the conservation of viability and ecological competence after application. With this in mind studies were conducted to develop formulations of P. anomala which would have these attributes. Cells were grown in molasses-based medium modified with proline to different water availability levels (0.98 and 0.96) which significantly increased (up to 50%) the content of trehalose and arabitol in the yeast cells during liquid broth fermentation. The use of isotonic solutions for harvesting the yeast cells further increased the endogenous content of these compatible solutes as well as glycerol. Fluidised bed drying of cells at 30–80°C was carried out for 10 and 20 min and showed that viability was significantly decreased at 70–80°C. A temperature of 50°C for 20 min was found to be best for viability (70%) and moisture content of <10%. Several additives for conservation of viability showed that cotton seed flour+skimmed milk was the best treatment when dried at 50°C. The biocontrol efficacy of formulated P. anomala cells was tested in laboratory scale studies and this showed that they inhibited growth of Penicillium verrucosum and reduce ochratoxin A production in moist wheat grain under some combinations of water availability. Physiologically modified formulated yeast cells with increased levels of trehalose and arabitol gave similar efficacy as fresh cells. This suggests that ecophysiological manipulation of such BCAs can result in improved ecological competence of such formulations and effective biocontrol.

Einfluss der Getreideart auf physikalische Kenngrößen von Feuchtgetreide

Due to increasing energy costs, interest in utilising moist grain is increasing. Experiments with grain species have shown that there are significant differences in physical parameters, which are important for maintaining the quality of the preserved moist grain.

Post-harvest control strategies: Minimizing mycotoxins in the food chain

Contamination of cereal commodities by moulds and mycotoxins results in dry matter, quality, and nutritional losses and represents a significant hazard to the food chain. Most grain is harvested, dried and then stored on farm or in silos for medium/long term storage. Cereal quality is influenced by a range of interacting abiotic and biotic factors. In the so-called stored grain ecosystem, factors include grain and contaminant mould respiration, insect pests, rodents and the key environmental factors of temperature, water availability and intergranular gas composition, and preservatives which are added to conserve moist grain for animal feed. Thus knowledge of the key critical control points during harvesting, drying and storage stages in the cereal production chain are essential in developing effective prevention strategies post-harvest. Studies show that very small amounts of dry matter loss due to mould activity can be tolerated. With < 0.5% dry matter loss visible moulding, mycotoxin contamination and downgrading of lots can occur. The key mycotoxigenic moulds in partially dried grain are Penicillium verrucosum (ochratoxin) in damp cool climates of Northern Europe, and Aspergillus flavus (aflatoxins), A. ochraceus (ochratoxin) and some Fusarium species (fumonisins, trichothecenes) on temperate and tropical cereals. Studies on the ecology of these species has resulted in modelling of germination, growth and mycotoxin minima and prediction of fungal contamination levels which may lead to mycotoxin contamination above the tolerable legislative limits (e.g. for ochratoxin). The effect of modified atmospheres and fumigation with sulphur dioxide and ammonia have been attempted to try and control mould spoilage in storage. Elevated CO 2 of > 75% are required to ensure that growth of mycotoxigenic moulds does not occur in partially dried grain. Sometimes, preservatives based on aliphatic acids have been used to prevent spoilage and mycotoxin contamination of stored commodities, especially feed. These are predominantly fungistats and attempts have been made to use alternatives such as essential oils and anti-oxidants to prevent growth and mycotoxin accumulation in partially dried grain. Interactions between spoilage and mycotoxigenic fungi and insect pests inevitably occurs in stored grain ecosystems and this can further influence contamination with mycotoxins. Effective post-harvest management of stored commodities requires clear monitoring criteria and effective implementation in relation to abiotic and biotic factors, hygiene and monitoring to ensure that mycotoxin contamination is minimised and that stored grain can proceed through the food chain for processing.

Feuchtgetreidesilierung im Folienschlauch

A well known method from the 1970's using bagging machines to preserve forage in silage bags has been further the developed for moist grain. Since 2005 it has been used for storing moist grain on farms. Preliminary investigative results for this procedure are presented in the following.

Water, temperature and gas composition interactions affect growth and ochratoxin A production by isolates of Penicillium verrucosum on wheat grain

To examine the effect of interactions between water, temperature and gas composition on growth and ochratoxin A (OTA) production by isolates of Penicillium verrucosum in vitro and in situ on grain-based media and wheat grain. Three isolates of P. verrucosum were examined in relation to radial growth rate and OTA production, and to interacting conditions of water activity (a(w)), temperature and gas composition on a milled wheat medium. Subsequently, detailed temporal studies were carried out on gamma irradiated wheat grain over the range 0.75-0.995 a(w), 10-25 degrees C and air, 25 or 50% CO(2). This showed that optimum growth of P. verrucosum was at 0.98 a(w) in vitro at 25 degrees C, but at 0.95 a(w) and 25 degrees C on wheat grain. The a(w) minimum for growth was about 0.80 a(w), although no OTA was produced under this condition even after 56 days. Significant inhibition of growth and OTA production occurred with 50% CO(2), and 0.90-0.995 a(w) at 25 degrees C. The optimum and marginal conditions for growth and OTA production on wheat grain have been identified. At least 50% CO(2) is needed to inhibit growth and OTA production by >75% in moist grain (0.90-0.995 a(w)). First detailed identification of optimal and marginal interacting conditions of water/temperature and gas composition on growth and OTA production by P. verrucosum on wheat grain. This is a critical component of the postharvest management strategy for minimizing contamination by this important mycotoxin and predicting risk, based on environmental conditions, during drying and storage.

Comparative yield and chemical composition of two varieties of narrow-leafed lupin ( Lupinus angustifolius) when harvested as whole-crop, moist grain and dry grain

An experiment was conducted to determine the yield and chemical composition of narrow-leafed or blue lupins ( Lupinus angustifolius) when harvested as whole-crop silage, crimped grain and dry grain. A branching variety (cv. Bordako) and a single-stemmed variety (cv. Borweta) were sown in spring. The crops were harvested for whole-crop silage at growth stage 4.5 (green pod, septa split). Following a 24 h wilt and inoculant ( Lactobacillus plantarum) application the forage was ensiled in 10 kg mini-silos for 90 days. The moist grain was harvested when the crop reached a target grain DM of 700 g kg −1. After crimping an acid additive was applied, and the grain ensiled in 10 kg mini-silos. The dry grain was harvested when the DM content of the grain had reached 850 g kg −1. The chemical composition of the whole-crop silages was similar, with CP concentrations of over 190 g kg −1 DM. However, the forage yield of Bordako (8446 kg DM ha −1) was significantly higher than that of Borweta (6622 kg DM ha −1). In contrast, the yields of moist and dry grain were higher for Borweta due to lodging of the Bordako stand (3666 kg DM ha −1 versus 1707 kg DM ha −1 and 2863 kg DM ha −1 versus 1442 kg DM ha −1 for moist and dry grain, respectively). The CP concentrations of the moist and dry grain produced by Bordako (both 360 g kg −1 DM) were significantly higher than that produced by Borweta (300 g kg −1 DM). The results suggest that while the branching variety Bordako is better suited to whole-crop production because of its substantially higher DM yield, the earlier ripening and more robust stand of the single-stemmed Borweta make this variety more appropriate for grain production.