Fumigation trials with a mixture of methyl bromide and carbon dioxide in vertical bins

The efficacy of a fumigant mixture containing methyl bromide and carbon dioxide was examined using the gravity penetration method in vertical bins of wheat. When applied as the mixture methyl bromide penetrated to the bottom of the bins and complete control of test insects at the base of the bins as well as the existing natural infestation was obtained. Methyl bromide applied alone under similar conditions was not detected at the bottom of the bins and the insects of the natural infestation, and test insects remained alive. It is assumed the carbon dioxide acted as a carrier and facilitated the penetration of the methyl bromide to the depth of 17 m through the grain bulk.     

Movement of halogenated fumigants through wheat

The movement of fumigants was studied by gas chromatography on columns of wheat coupled directly to a detector. The fumigants were methyl bromide, methylene dichloride, carbon tetrachloride, chloropicrin and ethylene dibromide. Their chromatographic behaviour was the same with carbon dioxide as carrier gas as with air or nitrogen. Improved distribution of fumigants added with carbon dioxide in silos is attributed to other factors and not to changes in the dynamics of adsorption of fumigant to wheat.     

Changes in the vitamin content of various cereals during storage

Thiamine and niacin losses were studied in various cereals (grinding millet, non-grinding oatmeal, fine-ground corn, grinding rice, wheat Poltavskaya, buckwheat, pearl-barley, and grinding pea) stored in sacks at store-houses in two different climatic areas of the USSR - with a temperate and with a dry hot climate, as well as at a constant temperature of 10 degrees C, during 6-29 months. Vitamin losses in grinding millet, non-grinding oatmeal and grinding rice were evaluated considering their treatment with methyl bromide and cereal cooking. It was found that during the storage under conditions of a dry hot climate thiamine and niacin losses comprised 37.8, after methyl bromide treatment - 44.0, and after cooking - 28.6%. Lower vitamin losses were recorded after the cereals storage at a constant temperature of 10 degrees C.     

Methyl bromide—Is there any future for this noteworthy fumigant?

For many years methyl bromide has played a significant role in controlling insect pests in durable and perishable agricultural commodities, pests in the soil and in structures. Although about 10% of the chemical produced is used globally for disinfesting stored products its importance for that purpose cannot be understressed, since it is the only remaining fumigant in worldwide use other than phosphine. Methyl bromide is the only fumigant available for quarantine treatment of commodities where rapid disinfestation techniques are essential. Although methyl bromide arises from natural sources, principally the oceans, most of the chemical found in the stratosphere is now thought to originate from man-made sources. Methyl bromide has been formally listed as an ozone-depleting substance by the Parties to the Montreal Protocol, with agreement from 1995 to limit future production. Reviews of both the current uses of methyl bromide, and of potential substitutes should permit a decision on a general control scheme for the chemical by 1995. Separately, in the U.S.A., under the Clean Air Act, methyl bromide will be phased out by the year 2001. Other countries or political unions are also currently examining the feasibility of reducing the quantities of methyl bromide used. Future restrictions on methyl bromide are expected to have a particular impact on developing countries, particularly those exporting agricultural products. This has been recognized in exempting these countries from the controls to be introduced in 1995. Despite many uncertainties regarding its role in ozone depletion it seems certain that methyl bromide will, eventually, be removed from the list of the few remaining products capable of preventing pest damage to food and other valuable commodities.     

Residues after fumigation with methyl bromide: bromide ion and methyl bromide in middlings and final cereal foodstuffs

Methyl bromide and bromide ion concentrations were estimated in pasta manufactured before and after fumigation with methyl bromide. The first trial estimated the bromide ion concentrations in fumigated and unfumigated flours and in pastas obtained from these. The concentration of bromide ions in fumigated flours was not significantly different from unfumigated flours. Only some pastas, manufactured from fumigated flours, showed a higher bromide ion concentration than those manufactured from unfumigated flours. The second trial evaluated the bromide ion concentrations of rices, white flours, flours, pastas made only from flours, pastas with eggs and pastas with eggs and spinach, before and after exposure to methyl bromide in their retail packagings. The bromide ion concentrations in fumigated pastas with eggs, pastas with eggs and spinach and rice were higher than in those unfumigated. In the pastas with eggs the bromide ion concentration after fumigation increased ten times (from about 4 to 40 mg/kg). Results showed that the bromide ion and methyl bromide levels estimated in all the foodstuffs examined were lower than the maximum limits fixed by several different national regulations.     

樱桃中溴形态分析方法及其在熏蒸过程追溯中的应用

建立樱桃中溴形态的分析方法,对比未熏蒸与熏蒸后樱桃中溴甲烷残留量和无机溴含量,研究溴甲烷熏蒸与溴残留的关系。采用水超声提取,以36 mmol/L硝酸＋67 mmol/L氨水作为流动相,经阴离子色谱柱分离,高效液相色谱-电感耦合等离子体质谱法分析樱桃中的溴形态,并使用电感耦合等离子体质谱法确证樱桃中总溴含量,顶空进样-气相色谱法检测樱桃中溴甲烷残留量。研究表明,溴形态分析方法中溴酸根的回收率在89.7%～101.4%之间,相对标准偏差为2.1%～3.5%,溴离子回收率为85.5%～107.3%,相对标准偏差为4.4%～7.0%,定量限为0.10 mg/kg。溴甲烷熏蒸后樱桃中只含有溴离子,其含量与总溴含量相符。熏蒸后樱桃中的溴甲烷残留量随时间递减,溴离子含量明显高于未熏蒸,且不受时间与保存条件的影响产生显著变化。本方法可对樱桃的溴甲烷熏蒸过程进行追溯,为水果的进出口风险监控和质量控制提供依据。     

A review of the properties and usage of methyl bromide as a fumigant

The properties which make methyl bromide an effective fumigant and the range of commodities treated with it are reviewed. The problems associated with the various situations in which fumigations are carried out and the methods of application used are discussed, and consideration is given to the toxicity of methyl bromide to man and other mammals, and to the risks involved in its use. Analytical methods for determining methyl bromide in air and residual bromide in foodstuffs are reviewed and a Table of physical properties and other reference data is given as an Appendix.     

SELECTED ALTERNATIVES TO METHYL BROMIDE IN THE POSTHARVEST AND QUARANTINE TREATMENT OF ALMONDS AND WALNUTS: AN ECONOMIC PERSPECTIVE

Methyl bromide is a highly effective fumigant used in the postharvest and quarantine treatment of tree nuts. There will be a complete phase out in the United States of America (U.S.) of methyl bromide by 2005 according to The Montreal Protocol of 1991 with the exception of preshipment and quarantine uses as stated in the 1998 Clean Air Act. This study analyzed alternative treatment scenarios. The alternatives considered were phosphine, irradiation, and controlled atmosphere storage. Costs for each scenario were developed. Cost increases with irradiation ranged from two to fourteen times the benchmark costs for methyl bromide. Controlled atmosphere storage for both commodities had cost increases ranging from 174% to 256% over methyl bromide costs. Phosphine was used only to treat almonds. Phosphine application costs were 108% and 117% above the benchmark costs for methyl bromide.     

几种土壤熏蒸剂防除烟草苗床杂草的药效试验

对35%"线克"水剂、98%"必速灭"微粒剂、32 7%"维博亩"水剂、32 7%"斯美地"水剂、33 6%"适每地"水剂、98%"棉隆"微粒剂和98%溴甲烷压缩气体等7种不同土壤熏蒸剂防除烟草苗床杂草效果进行了试验。结果表明,7种土壤熏蒸剂对苗床杂草均有较好的防除效果。播种后20d、40d时各处理对杂草数量的平均防效均分别达到95%和90%以上,几种试验药剂与对照药剂溴甲烷相当,可替代溴甲烷在烟草苗床除草中应用。     

我国烟草苗床甲基溴替代研究现状及展望

溴甲烷是一种高效、广谱的土壤熏蒸剂,在我国烟草苗床上广泛使用,由于显著消耗臭氧层,需要寻找有效替代技术。本文综述了国内外甲基溴替代技术研究现状,对我国烟草苗床替代技术进行了分析,并对我国育苗过程中存在的问题作了探讨,提出通过育苗技术和苗床害物IPM策略结合,可望有效替代甲基溴,实现良好的社会、生态和经济效益。      

The toxic action of phosphine in combination with some alkyl halide fumigants and carbon dioxide against the eggs of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae)

The toxicity of phosphine, three alkyl halide fumigants (ethylene dibromide, methyl bromide and methyl iodide), carbon dioxide, mixtures of phosphine + alkyl halide fumigants, and phosphine + carbon dioxide, to 1-, 2-, and 3-day-old eggs of Tribolium castaneum Herbst was studied. Combinations of phosphine and alkyl halide fumigants showed antagonism as evidenced by their joint action ratios at the LD₉₀ (< 1). The mortality data indicated that mixtures of phosphine and carbon dioxide were more effective than either alone. At LD₅₀, the order of toxicity of the individual fumigants for a 24 hr exposure and on a weight basis (mg fumigant/litre of air) was: phosphine > methyl iodide > ethylene dibromide > methyl bromide. A decline in susceptibility of eggs with age for methyl bromide and ethylene dibromide and a peak tolerance at 2 days for carbon dioxide were noted.     

Exposure of meat to methyl bromide during refrigerated-store pest control; residues in beef and lamb and effect on quality

Beef and lamb were exposed to methyl bromide in a refrigerated container during trial fumigations at 1, 3 and 10 times the level considered necessary for rodent control in cold-store insulation material. Traces of residual methyl bromide were detected by GC-MS in fats after periods of up to 3 months in refrigerated storage and some effect on taste and odour after roasting was noted in beef subjected to the highest treatment level.     

溴甲烷熏蒸对不同苹果品种贮藏品质的影响

不同温度条件下溴甲烷熏蒸处理5个不同品种的苹果,以明确溴甲烷熏蒸对中国生产的苹果的呼吸强度、果皮色泽、硬度、可溶性糖、总酸度等品质指标的影响,为建立苹果溴甲烷检疫熏蒸处理技术标准提供依据。结果表明,溴甲烷熏蒸在30℃下对5个品种苹果呼吸无显著影响,在15、20℃下能降低富士、青冠、金冠、青苹果在熏蒸期间的呼吸速率,其他温度无明显规律;15℃以下熏蒸处理的富士、金冠在贮藏期间呼吸强度较对照显著提高,20℃以上5个品种苹果在贮藏期间呼吸强度较对照无明显变化;各处理温度下对富士、青苹果色泽有显著影响,富士、青冠在20℃以上处理后硬度显著提高,对5种苹果可溶性糖无显著影响,富士的总酸度在15℃以上显著提高,其他品种无显著影响。可以用于这5个苹果品种溴甲烷熏蒸处理条件为:10℃、64g/m3可用于青冠、青苹果,15℃、48g/m3可用于青冠、青苹果,20℃、40g/m3,可用于青冠、花牛、青苹果,25℃、32g/m3,适用于富士、青冠、花牛、青苹果,30℃、24g/m3可用于5个品种的处理。     

Efficacy of sensor assisted vacuum hermetic storage against chemical fumigated wheat

Alternatives to chemical fumigation, are being explored as the popular fumigants like methyl bromide and phosphine are being phased out for their ozone depleting nature and insect resistance, respectively. Vacuum hermetic storage has potential for storage of agricultural durable commodities without fumigants and can eliminate 99% of insect infestation. In present research, the vacuum hermetic storage was tested in field with assistance of sensors and compared with the conventional phosphine fumigated storage by grain quality assessment and interstitial atmosphere for six months. Relative humidity of the hermetic bags remained below 25%, whereas temperature followed the same pattern as of the ambient. Germination percentage, thousand kernel weight and besatz content did not change significantly (p > 0.05), whereas mould count and moisture content reduced over the storage time compared wheat stored in metal bin.     

Effects of two fumigants and a fungicide formulation on the development of kiln brown stain in radiata pine lumber

Two fumigants (methyl bromide and sulphuryl fluoride) were used to treat freshly sawn radiata pine (Pinus radiata D. Don) lumber and log sections to evaluate their influence on development of kiln brown stain. Both treatments reduced severity of stain when compared with controls. The sulphuryl fluoride treatment was notably better than methyl bromide at the highest fumigant dosage, but levels of overall stain were still considered unacceptable with only 20–30% of lumber having either no or slight stain beneath the surface. Sulphuryl fluoride showed superior penetration into sapwood compared to methyl bromide as determined by a colour assay of parenchyma cell viability. A fungicide formulation which was successful in preventing brown stain in kiln dried eastern white pine was ineffective against kiln brown stain in radiata pine. The results of the present study indicates that the mechanism for kiln brown stain in radiata pine differs from that in eastern white pine.     

Dissipation of organophosphorus pesticides in wheat during pasta processing

For investigating the carryover of some organophosphorus pesticide residues in the cereal food chain from grain to consumer, a study was set up on durum wheat, semolina and pasta. Pesticide-free durum wheat was placed into a small-scale model of a commercial storage vessel and treated with pesticides (malathion, fenitrothion, chlorpyrifos methyl, and pirimiphos methyl) according to the raw material legislation of Turkey. The residue levels of insecticides were determined in wheat, semolina, and spaghetti produced from stored wheat at various time intervals during five months of storage. A multiresidue analysis was performed using GC equipped with an NPD. The confirmation was performed by GC–MS. The residue levels of insecticides in wheat exceeded the maximum residue limits (MRLs) for wheat. The storage period was generally not effective enough to reduce the residues in wheat to levels below the MRLs. Although a considerable amount of the insecticides remained in the semolina, spaghetti processing significantly reduced residue concentrations in general. Pirimiphos methyl was the most persistent of the insecticides and comparatively less substantial loss occurred during milling and spaghetti processing due to its physicochemical properties.     

Toxicity and uptake of methyl bromide in hybrid descendants of resistant and susceptible Sitophilus granarius (L.)

Progeny of susceptible Sitophilus granarius repeatedly crossed with individuals from a resistant strain attained resistance to methyl bromide without selection with the fumigant and when this hybrid strain was subsequently subjected to methyl bromide pressure a higher degree of resistance than was present in the resistant parent developed. Resistant insects absorbed slightly less fumigant than susceptible insects in the first few hours of exposure but more in a 24 hr fumigation period. Resistance could not be related to either rate or degree of uptake of fumigant. The quantities of absorbed fumigant required to kill insects from both strains are given.     

Brommethan- und Bromidgehalte in Samenkernen nach Vorratsschutz-Begasung und verschiedenen Verarbeitungsverfahren

Zusammenfassung Im Anschluß an eine 24stündige Brommethan-Begasung mit 30 g/m³ wurden Mandel-, Haselnuß-, Erdnuß- und Kakaokerne bis zu 14 Tage nach der Behandlung einigen Bearbeitungsprozessen der Süßwarenindustrie unterworfen. Anschließend erfolgte eine gaschromatographische Bestimmung der Brommethanund Bromidgehalte. Anteilig entstandenes Bromid wurde mit einer ionensensitiven Elektrode erfaßt. Brommethan diffundierte nach Zerkleinerung schneller aus den Produkten heraus. Wärmeeinwirkung bei Verarbeitungsprozessen wie Brühen und Rösten führte zu schneller Verminderung der Brommethangehalte. Beim Rösten erhöhten sich aber die Bromidrückstände. Der Bromidgehalt wurde lediglich durch Brühen der begasten Produkte vermindert und blieb nach Zerkleinerung sowie Schälen unverändert. In Kakaobohnen wurde der überwiegende Anteil des Bromids in den Schalen gefunden.

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Residues of methyl bromide and bromide in fumigated seed kernels following different industrial processes

Summary Almonds, hazelnuts, ground-nuts and cocoa beans were treated with methyl bromide for one day at about 30 g/m³. The produce was stored and treated by a process derived from the food processing industry. The measurement of methyl bromide was carried out using gas chromatography. Bromide contents were determined by an ion-specific electrode technique. Methyl bromide desorption was enhanced by grinding the fumigated produce. Heat treatment, such as scalding, peeling or roasting, lead to pronounced reduction of the methyl bromide content but with the disadvantage of an increase in bromide ion content. Of all the tested processes, only the application of (hot) water reduced the amount of residual bromide. Most of the residual bromide in fumigated cocoa beans could be found in the shells.

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Diese Arbeit ist ein Teil der Dissertationsarbeit (D 83, FB 13 Nr. 289) von A. Franz an der Technischen Universität Berlin, Fachbereich 13 (Lebensmittel- und Gärungstechnologie)     

Adsorption of Methyl Orange on Starches

Adsorption characteristics of methyl orange were investigated on kudzu, sweet potato, corn, rice, wheat, potato and snake gourd starches. No adsorption of methyl orange, an anionic dye, was observed on potato starch and snake gourd starch because of the presence of phosphate esters. Adsorption isotherms were found to fit both the Langmuir equation and Freundlich equation in all others. The degree of adsorption by kudzu, sweet potato, corn and wheat starches was related to the number of hydroxyl groups. We suggested methyl orange was confined to a monolayer on surface hydroxyl groups of the starches.     

Effect of methyl bromide on the embryonic development of Acarus siro L. (Acarina: Acaridae)

The first mitotic divisions of the fertilized egg of Acarus siro occur within the female's reproductive system. The egg is laid at the time of the formation of the germ band.The integument of the methyl bromide-treated egg became non-elastic, sticky and soft. Yolk globules of eggs treated before cleavage occurred had completely disintegrated. At segmentation of the embryo the fumigant caused some abnormalities in the size of egg rudiments and in the depth of furrows separating segments. Changes in the developing nervous system were also evident.Three periods of sensitivity were distinguished in eggs fumigated with methyl bromide (1) Before the start of gastrulation movements in the germ band; (2) The formation of the central nervous system; (3) The period preceding dorsal closure. The possible mechanisms of sensitive periods to methyl bromide in the embryonic development of Acarus siro L. are discussed.