Microflora of stored grain in international trade

Although the temperature of grain in the holds of ships arriving in Japan from Argentina, Australia, Canada, China and USA during 1966–67 varied with the grain, country of origin, and season, it was likely to be determined by the temperature of the grain when it was loaded into the ships. Dockage level varied among bulks of the same type of grain, but the mean dockage in any one crop was always larger when originating from the USA than from other countries. Generally the viability of the grain was good, but when it was reduced, interaction of variety and time seemed to be the principal cause. Field fungi — non-pathogenic Alternaria, and the pathogenic Helminthosporium and Fusarium species — tended to die out, during transport, thus reducing the hazards of new pathogenic strains being distributed across international boundaries. The non-pathogenic field fungi, Cladosporium and Phaeoramularia, were persistent. Although common in grain shipments from all countries, species of Aspergillus and Penicillium varied quantitatively with the different grains. In this respect, more Aspergillus spp. were found in grains originating in the USA and Australia than those originating in Canada. The primary contamination by storage fungi appeared to be at the source, at or after harvest and in storage prior to export.     

储粮环境挥发性化合物与储粮害虫的关系研究进展

每种粮食的储粮环境中都存在有其特征性挥发物,储粮害虫的发生对储粮环境中挥发物具有重要影响。本文简述了顶空式固相微萃取法、浸入式固相微萃取法、电子鼻检测法等储粮挥发物的提取方法及其优缺点,对小麦 Triticum aestivum L.、稻谷 Olyza sativa L.、玉米 Zea mays L.和燕麦 Avena sativa L.等主要储藏粮食种类的挥发性化合物成分、粮食挥发物对昆虫行为反应的影响、主要储粮害虫(赤拟谷盗 Tribolium castaneum、锈赤扁谷盗 Cryptolestes ferrugineus 和象虫 Sitophilus spp.)发生与粮食挥发物的关系等研究进展进行综述,探讨了储粮环境挥发性化合物与储粮害虫关系未来的研究方向,以期对今后储粮害虫生态防治研究与应用提供参考信息。     

Diatomaceous earths as alternatives to chemical insecticides in stored grain

Diatomaceous earth （DE） is a natural inert dust used to control insect pests in stored grain as an alternative to synthetic residual insecticides. Various DE formulations are now registered as a grain protectant or for structural treatment in many different countries throughout the world. The mode of action of DE is through the absorption of cuticular waxes in the insect cuticle, and insect death occurs from desiccation. The main advantages of using DE are its low mammalian toxicity and its stability. The main limitations to widespread commercial use of DE are reduction of the bulk density and flowability of grain, irritant hazards during application and reduction in efficacy at high moisture contents. This paper is an updated review of published results of researches related to the use of DEs and discusses their potential use in large-scale, commercial storage and in small scale applications.     

Genetic approaches to reducing losses of stored grain to insects and diseases

Insects and diseases devour or damage a fifth or more of stored food grains each year in many parts of the world. Modern breeding and genomics promise progress in characterizing the resistance to the pests responsible for these losses that is present in the vast and diverse gene pool of cereals, as well as advances in incorporating this resistance into productive and acceptable crop varieties. The impact of such varieties could be dramatic in developing countries, where grain infestations are most common and harmful, and where surging populations require affordable food.     

Ethanol and acetaldehyde in imbibing soybean seeds in relation to deterioration

Deterioration as evidenced by decline in germination or seedling growth of soybean (cv. Essex) seeds during accelerated aging treatments at 41 C and 100% relative humidity is accompanied by increased levels of acetaldehyde and ethanol in imbibing embryonic axes and seeds. These increases become more pronounced with duration of the aging treatment. A similar inverse relationship between levels of acetaldehyde and ethanol and deterioration was observed when seeds were “naturally” aged for several years. During imbibition of low-vigor, accelerated-aged seeds at 25 C, acetaldehyde and ethanol increased from near trace amounts in dry tissues to maximum levels at 4 hours. Increases in acetaldehyde and ethanol during imbibition were less in high- than in low-vigor seeds. Increases were also less pronounced in low-vigor seeds when water uptake injury was avoided by osmotically decreasing water uptake rate with 30% polyethylene glycol. Embryonic axes from deteriorated seeds were characterized by low rates of O₂ uptake and high respiratory quotients relative to the unaged controls. Anaerobic conditions and respiratory inhibitors, such as sodium azide, increased acetaldehyde and ethanol in unaged seeds to levels similar to those in accelerated-aged seeds after 2 hours imbibition. It is suggested that, during aging, an imbalance between tricarboxylic and glycolytic activities, present during early imbibition to some degree even in vigorous unaged seeds, becomes more pronounced and leads to accumulation of ethanol and acetaldehyde.     

Mould deterioration of feeding stuffs in relation to humidity of storage Part III. The isolation of mould species from feeding stuffs stored at different humidities

Isolations were made of mould species actively growing on a variety of feeding stuffs stored at fixed humidities between too and 65% for periods of up to 4 years. The factors influencing the species of moulds isolated were: (1) die relative humidity of the atmosphere; (2) the length of the storage period before the isolations were made; (3) the type and origin of die feeding stuffs from which the isolates were obtained.
A critical humidify existed for each species below which the development of mould spores could not take place. At relative humidities (R.H.) between 100 and 90% a large variety of moulds were able to develop. Members of die Mucorales and the Fungi Imperfecti were not isolated below 90% R.H. and, although ***Pemicillium app. flourished between 100 and 85% R.H., they were not isolated below 75% R.H. ***Aspergilhes app., on the other hand, were able to develop under conditions of very restricted moisture supply. Some members of the A. ***glaucus group were able to grow at humidities as low as 65-70%.
In general, the moat commonly occurring moulds on the feeding stuffs used in these trials were small ***ascospored species of the A. ***glaucus group, particularly A. ***repens and A. ruber. It is considered that it is these species that will most frequently cause mould damage to feeding stuffs in commercial stores.     

Factors determining the microflora of stored barley grain

Colonisation of barley grain has been studied during storage at different water contents and with and without restriction of the air supply to simulate conditions in unsealed silos. Grain stored with a water activity >0·9 a_w (20% water content) heated spontaneously when aeration was unrestricted, the maximum temperature attained increasing with a_w to 58 °C at 1·0 a_w (39% water content). The presence of many unripe grains increased the tendency to heat at a given mean water content. Although heating was prevented by sheeting to restrict the air supply, it could occur subsequently when the sheeting was removed. Both heating and restriction of the air supply were associated with increased carbon dioxide (to >25%) and decreased oxygen concentrations (to <5%). Germination of grain after 6·9 months storage was correlated with a_w; germination levels approaching 100% were retained only at about 0·7 a_w (13·5% water content). Colonisation by Aspergillus species was correlated with a_w and temperature and similar correlations with Penicillium species were also found, with P. verrucosum var. cyclopium abundant at 0·85-0·90 a_w (17·20% water content) and P. piceum, P. funiculosum and P. capsulatum at 0·90-0·95 a_w (20–25% water content). In sealed containers P. roquefortii occurred at 1·00 a_w (39% water content) and P. hordei at 0·90-0·92 a_w (20–22% water content). Spores of fungi and actinomycetes formed during spontaneous heating of grain survived 6 months sealed storage although Absidia corymbifera and Micropolyspora faeni may have declined in numbers. Fungicides applied to the ripening grain had only limited effect on the colonisation of the grain during storage.     

Ecology of fungi associated with moist stored barley grain

A study of the ecology of fungi associated with moist stored barley grain was carried out on samples from a partially sealed silo in Cumberland. Samples were collected during harvest and after storage at high moisture content in a partially sealed silo. At harvest, the field fungi Alternaria, Fusarium, Cladosporium and Mucor spp. were dominant both in the husks and in the dehusked, surface-sterilized grain but they were rapidly succeeded by the storage fungi: Aspergillus, Penicillium and Absidia spp. then constituted about 80 % of the initial invasion. At this stage internal grain infection rarely exceeded 5 % compared to 65–80 % infection in the husks. In subsequent months, there was a remarkable increase in invasion, mainly by Penicillium, Aspergillus and Absidia spp. and by yeasts, which appeared both in the husks and in dehusked grain. In the third month of storage, Penicillium cyclopium, P. roqueforti, Absidia corymbifera, Aspergillus candidus, A. terreus and yeasts became dominant. The thermophilous species Aspergillus fumigatus, A. terreus, Absidia corymbifera, Mucorpusillus and Dactylomyces crustaceus were isolated from husks and in dehusked grain incubated at 37 and 45 °C. Most grains were infected significantly by single genera.     

Fungi of certain stored vegetable seeds in relation to pre- and post-emergence effects

A number of fungi were found associated with stored cauliflower, common bean, and pea seeds, but onlyHelminthosporium sp. on cauliflower,Fusarium sp. on common bean, andAlternaria sp. on pea were proved pathogenic. Artificial inoculation tests withHelminthosporium sp.,Fusarium sp., andAlternaria sp. resulted in 30, 16.6, and 26.6 % pre-emergence injuries to cauliflower, common bean, and pea respectively. Also, these fungi were responsible for considerable post-emergence mortality of seedlings.

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Zusammenfassung Eine Anzahl von Pilzen sind mit dem Samen von Karfiol, Bohnen und Erbsen vergesellschaftet gefunden worden.Helminthosporium sp. nur an Karfiol,Fusarium sp. nur an Bohnen undAlternaria sp. nur an Erbsen haben sich als pathogen erwiesen. Küristliche Einimpfung mitHelminthosporium sp.,Fusarium sp., undAlternaria sp. gab positive Resultate in 30, 16.6, und 26.6 % bezw. in Karfiol, Bohnen und Erbsen. Diese Pilzen waren auch für das Absterben junger Pflanzen verantwortlich.

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Portion of a thesis submitted by the senior author to the Agra University, Agra, India, in partial fulfilment of the requirements for the degree of M.Sc. (Ag.).     

Free sugars in relation to starch accumulation in developing rice grain

The changes in sugars (water-soluble carbohydrates) were studied in the developing grain of rice (Oryza sativa L., variety IR28 and IR29) in relation to the role of these sugars as precursors of ADP glucose in starch accumulation. The levels of total sugars, total reducing sugars and free glucose, sucrose and other nonreducing sugars, maltooligosaccharides, and total and nonsucrosyl fructose followed closely the changes in the rate of starch accumulation, in both IR28 and 29; the peak value occurred 9 days after flowering. The level of soluble carbohydrates remained high in the caryopsis and also in milled rice after starch accumulation, suggesting that the supply of sugar precursors does not limit starch accumulation in the rice grain. Because of a higher level of reducing sugars, the level of free sugars in the grain of waxy rice IR29 was higher than that of nonwaxy IR28.     

The function of granulocytes stored in whole blood in relation to the storage time

Whereas numerous investigations and extensive experiences have been available for some years on problems of storing erythrocytes and thrombocytes, it was only recently that the storage of granulocytes with the aim at maintaining their function for a longer period has been given proper regard as a problem, which, however, could not be brought to a satisfactory solution. Primarily, attention is focused on specific cell physiology. At the same time it is necessary to have at hand a number of approaches covering as many partial aspects of the granulocyte function as possible to identify the functional damages or the extent of cell damage in connection with storage. In the present paper the behaviour of granulocytes under conditions commonly used in transfusion medicine for storing blood are investigated for a period of 4 days by controlling the total leukocyte and granulocyte values, pH value, osmolality, vitality test in the colour excluding test as well as by function tests such as behaviour of phagocytosis and NBT capability of reduction. A report is presented on the results of quantitative and qualitative changes in the investigated parameters.     

Compatibility of Bacillus thuringiensis and granulosis virus treatments of stored grain with four grain fumigants

Wheat was fumigated with phosphine, methyl bromide, CCl₄-carbon bisulfide (80:20 by volume), or ethylene dichloride-CCl₄ (75:25 by volume) after it had been treated with either of two formulations of Bacillus thuringiensis or with a granulosis virus of the Indian meal moth, Plodia interpunctella. Only methyl bromide had an adverse effect: the granulosis virus was inactivated. Spores of B. thuringiensis washed from treated wheat after fumigation with methyl bromide did not produce colonies on nutrient agar plates, but the activity of the B. thuringiensis against Indian meal moths was not affected.     

Fatty acid content and composition in relation to grain size of barley

The relationship between grain size and total fatty acid (TFA) content and composition, as well as the contribution of corn size distribution to the variation of fatty acid contents between barley types, were studied in nine barley varieties (six-rowed and two-rowed winter barleys, and two-rowed spring barleys) fractionated according to grain size. Smaller grains contained as much TFA as the bigger ones. On average, the proportions of saturated fatty acids (16:0 and 18:0) and of oleic acid (18:1) are higher in large grains than in small kernels, whereas the percentages of linoleic (18:2) and linolenic (18:3) acids are lower. The higher 18:1 and the lower 18:3 proportions in two-rowed barleys compared to their six-rowed counterparts, can be explained by the indirect effect of the different grain size distribution between the barley types.     

Mites associated with stored grain commodities in Benin, West Africa

After insects, mites are the major arthropod pests that inhabit stored agricultural products worldwide. To determine the acarofauna that infests cowpea, maize, paddy rice and sorghum in Benin (West Africa), surveys were conducted in some principal markets (Dantokpa, Glazoue and Parakou) of this country. A total of 555 samples of grains and debris were collected in May and September 2011. More than 56 species belonging to 24 mite families were recorded in the four products. These mite species included predators, parasites, fungivorous, phytophagous and other groups whose feeding habits are not well known. The family Cheyletidae was the most prevalent and the most diverse predatory mite family encountered, in which Cheyletus malaccensis Oudemans was the most abundant species. Several families of mite pests and mites responsible for allergies (Acaridae, Glycyphagidae, Pyroglyphidae, Pyemotidae and Saproglyphidae) were also detected. The three most dominant and frequent species were C. malaccensis, Suidasia nesbitti (Hughes) and Suidasia sp. Statistical analysis showed that densities of these three mite species were higher in Parakou than in Glazoue and Dantokpa, on one hand, and higher in debris than in grains, on the other hand. The densities of S. nesbitti and Suidasia sp. decreased significantly during the dry season, whereas C. malaccensis remained stable throughout the two samplings. Of all grains, sorghum was the least infested with mites. This study shows that in Benin mites are present in stored agricultural products to which they cause serious damage, and may cause various allergies to people.     

Efficacy of ozone fumigation against the major grain pests in stored wheat

Field experiments were conducted in steel bins containing 13,600 kg of hard red winter wheat, Triiticum aestivum L. One bin was treated with ozone and the second bin served as a control. Stored grain insects were placed in bins for 1-, 2-, 3-, and 4-d exposure periods in sampling tubes to test ozone concentrations of 0, 25, 50, and 70 parts per million by volume (ppmv). Ozone treatments on eggs and larvae of Plodia interpunctella (Hübner) were not effective, but pupae were more susceptible. Sitophilus oryzae (L.) adults were the most susceptible species with 100% mortality reached after 2 d in all ozone treatments. However, some progeny were produced at all concentrations and exposure periods. Tribolium castaneum (Herbst) adults had 100% mortality only after 4 d at 50 or 70 ppmv. No T. castaneum progeny were produced after 2-4 d at 70 ppmv. For Rhyzopertha dominica (F.), Cryptolestes ferrugineus (Stephens), and Oryzaephilus surinamensis (L.), 100% mortality was never achieved and progeny were produced at all ozone concentrations. Laboratory experiments, testing the effectiveness of ozone in controlling psocids, were conducted in two polyvinyl chloride cylinders each containing 55 kg of hard red winter wheat. Ozone treatment at a concentration of 70 ppmv was highly effective against adult female Liposcelis bostrychophila Badonnel and Liposcelis paeta Pearman after only 1 d of exposure. However, it was not effective against eggs of both species at all exposure periods. Ozonation has potential for the control of some stored grain insect pests on wheat.     

Maximum likelihood factor analysis of natural arthropod infestations in stored grain bulks

Interrelations between natural arthropod fauna and their environment were studied in 1964 from 165 samples collected from the same number of boxcars each containing about 54 tons of stored grain originating from various parts of Western Canada. Applications of several multivariate procedures, such as principal component and maximum likelihood factor analyses (unrotated, rotated and oblique solutions) were applied to 6 biotic and 3 environmental variates to obtain the clearest picture of interrelations among these variates.Jöreskog’ s computational procedure and computer programs were used for unrotated, rotated and oblique maximum likelihood solutions. A 3-factor hypothesis was developed; of the 3 factors the first 2 were significantly correlated (Correlation coefficient=0.78±0.15). The final confirmatory factor analysis revealed that: 1) the first factor indicates that acarine variates, Glycyphagus and Cheyletus, were correlated positively to each other but negatively with the insect Psocoptera, 2) the second factor indicates that the acarine variate Tarsonemus is correlated to moisture, dockage and the entomological variate Psocoptera, 3) the third factor indicates that the environmental factors are correlated to each other, and 4) the correlations between the third factor and the other factors are statistically different from zero.