舟山口岸进口鱿鱼中134Cs、137Cs比活度水平分析

目的：研究日本福岛核事故对舟山口岸进口鱿鱼中134Cs和137Cs比活度的影响。方法：选取北太、日本海、阿根廷和秘鲁4 个区域2011-2014年间310 份鱿鱼样品,采用高纯锗γ谱仪分析样品中134Cs和137Cs的比活度。结果：共检出阳性样品20 份,检出率为6.5%,其中北太鱿鱼占阳性样品的85.0%,134Cs的最高比活度为4.12×103 Bq/g,137Cs的最高比活度为6.89×103 Bq/g,远低于各国限量标准（最低限量为100×103 Bq/g）。结论：舟山口岸进口鱿鱼放射性核素134Cs、137Cs比活度低于10.0×103 Bq/g,不会危害食品质量安全,但是北太和日本海鱿鱼相对检出率高,应给予一定的关注。     

《食品工程》2015年总目次(总第134-137期)

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日本核电站事故对蘑菇的放射性污染(137Cs)特征及去除污染的研究进展

日本福岛核电站事故导致大量人工放射性物质释放到环境中。蘑菇可以将周围环境的放射性物质富集在子实体内, 使其在生态系统中循环, 而消费者可能误买误食受污染蘑菇, 造成放射性物质在人体内蓄积。通过查阅大量文献发现: 蘑菇中放射性铯来源有多种, 主要源自其生长的底物; 蘑菇中放射性铯含量高低, 与距事故发生地的距离和蘑菇自身的营养机制有着很大关系; 去除放射性物质, 可以通过减少环境中的放射性铯或者简单水煮、油炸来减少食用蘑菇的放射性。本文就蘑菇中放射性铯的来源, 积累方式, 产生差异的原因及去除方法进行概述, 以期为我国构建蘑菇类放射性污染特征及去除污染方法数据库提供支撑。     

食品及环境样品中肠球菌快速检验方法的 建立及优化

目的建立并优化食品及环境样品中肠球菌的快速检验方法。方法用mEI培养基作为选择性培养基,肠球菌tuf基因为靶基因设计引物,建立食品及环境样品中肠球菌的快速检验方法。通过添加肠球菌和非肠球菌标准菌株,验证方法的检测限、灵敏度及特异性,并使用优化后的方法对北京市丰台区某大型生鲜猪肉集贸市场的地面、墙壁、污水和生鲜猪肉等样品中的肠球菌进行检验。结果所建方法的检测限为1 CFU/100cm2和1 CFU/25 g(mL),且与10种非肠球菌无交叉反应;地面涂抹、墙壁涂抹、污水和生鲜猪肉等样品中均检验出肠球菌,检出率为100%。结论建立了简便、快速、灵敏、特异的肠球菌检验方法;集贸市场内部环境和生鲜猪肉存在肠球菌污染。应加强市售生鲜肉中肠球菌的监测,并采取相应措施降低其污染水平。     

δ~(13)C_H值小于δ~(13)C_P值的蜂蜜样品的综合鉴评

为加强蜂蜜真实性监测,从124份市面蜂蜜样品中筛选出51份δ13CH值(蜂蜜的δ13C值)小于δ13CP值(蜂蜜中蛋白质的δ13C值)的蜂蜜样品,采用元素分析-同位素质谱联用技术(EA-IRMS)、液相色谱-同位素质谱联用技术(LC-IRMS)以及液相色谱测定蜂蜜还原糖含量等多种检测手段,通过检测这些蜂蜜样品的系列稳定碳同位素比值、还原糖和蔗糖含量,对δ13CH值小于δ13CP值的蜂蜜样品进行了综合分析。结果表明:51份源于δ13CH值小于δ13CP值无法检测碳-4植物糖的样品,δ13CH值皆小于-23.5‰,2份样品还原糖含量低于60 g/100g,1份样品蔗糖含量超标,含量为7 g/100g,目前常规检测方法难以有效鉴评δ13CH值小于δ13CP值蜂蜜样品的真实性。将δ13CP-H(δ13CP-δ13CH)、Δδ13CF-G(δ13CF-δ13CG)、Δδ13Cmax(各类糖组分δ13C值的最大差值)以及寡糖检出等指标纳入综合鉴评,发现51份蜂蜜样品中的47份存在掺假掺杂嫌疑,所占比率高达92.16%,掺假掺杂主要以添加碳-3植物源转化产物为主,掺假原料可能是多类物质的复配组合。     

食品中Cr(Ⅲ)和Cr(Ⅵ)分离及ICP-MS法测定研究

本文报道了食品中Cr(Ⅲ)和Cr(Ⅵ)分离并用ICP-MS仪进行测定方法．食品经微波消化后，用离子交换树脂进行交换，以^45Sc为内标元素，采用内标法进行测定。该方法加标回收率是98．6％-99．6％，相对标准偏差RSD是2．1％～3．5％，检测限是0．006-0．01ng／ml，可用于食品以及饮用水、废水中Cr(Ⅲ)和Cr(Ⅵ)的测定。     

~(14)C用于天然食品添加剂的检测

粮食、水果、蔬菜、畜禽、鱼类中放射性同位素14C,原与大自然的14C是交换和平衡的,一旦收获、屠宰、宰杀,光合作用虽停止,14C平衡被破坏,但仍有14C-β放射性,只是其衰变率遵循指数函数(随时间而衰减)。石油与煤是埋藏于地下的腐烂植物,经3亿年以上的生化反应变迁而成,大大超过14C的10个半衰期,14C-β放射性早已衰变完不再存在,以石油热裂化气、天然气、煤干馏产品(煤焦油)为主要原料,通过基本有机合成与异构化、聚合、氢化、氧化等有机化学反应生产的合成添加剂,不含有放射性同位素14C。该原理可用来检测食品添加剂的14C-β放射性,确定生产原料是否为农副产品或有机化学合成产品,以及天然食品添加剂中是否混有合成添加剂。真实性检测步骤,将液体或固体食品添加剂样本通过不同的预处理和分离纯化制成闪烁液,采用液体闪烁计数器(经14C标准物质校正)测定其14C—β放射性,然后将数据与工作曲线进行分析与比较。     

食品中有害物质分析样品的制备

食品种类繁多, 涵盖范围广泛, 样品预处理就成为实验室检测步骤中关键的一步。本文简述了食品样品预处理过程中保障结果准确性和重现性的几个重要方面, 以最大残留限量为例, 比较了我国和其他国家及组织规定的分析部位, 讨论了一些需要注意的问题。以Gy采样模型中易测可控的样品颗粒大小为重要参数研究了其对样品缩分及均匀度的影响, 和冷冻捣碎机的优点及以后可能的应用, 最后简要地强调了样品存储的重要性。     

食品中蛋白质的功能(六) 食品中蛋白质的功能性质(三)——大豆蛋白和小麦蛋白

大豆蛋白和小麦面筋蛋白都是优良的植物蛋白,具有多种独特的功能性质,对改善制品的感官和食用品质有较好作用,广泛应用于食品领域。本文分别对大豆蛋白和小麦蛋白的特性以及在各类食品中的应用进行了较为全面的综述。     

Distribution of radiocaesium (137Cs) and radiopotassium (40K) during the cheese production

Distribution of radionuclides depends on various factors, and milk processing into cheese is recommended as one of the significant measures of radiation protection during radioactive contamination of the environment. A total of 16 milk and 16 cheese (soft and hard) samples were examined using HPGe gamma-ray spectrometry to obtain ¹³⁷Cs and ⁴⁰K activity concentrations. The Pearson's correlation coefficients between ¹³⁷Cs and ⁴⁰K were determined (0.73, 0.68, 0.19, −0.23), followed by determination of distribution of ¹³⁷Cs and ⁴⁰K from cow milk to two types of cheeses using food processing retention factors (0.07–0.34). Transfer of ¹³⁷Cs obtained could serve a great purpose for predicting its distribution during cheesemaking.     

Global distribution of radionuclides (137Cs and 40K) in marine mammals

Concentrations of anthropogenic radionuclides were measured in the muscle of marine mammals collected from various locations all over the world, and the global distribution of 137Cs in marine mammals was investigated. 40K was detected in all the specimens of marine mammals with no apparent difference between regions. An anthropogenic radionuclide, 137Cs, was detected in most of the species of marine mammals. With regard to the worldwide distribution of 137Cs, the highest concentration was noticed in the U.K. coast, followed by Lake Baikal, and decreases toward the southern sampling points. A strong positive correlation was observed between 137Cs levels in the muscle of marine mammals and the ambient seawater. Marine mammals feeding on fishes showed a higher concentration factor (CF) for 137Cs than those feeding on cephalopods. To our knowledge, this is the first report on the global distribution of 137Cs and the effect of feeding habits on the CF values of 137Cs in marine mammals.     

Cesium 134 and 137 contamination of game killed in Hesse

The amount of caesium 134 and 137 in Hessian game hunted for food (556 animals) after the reactor accident at Chernobyl was investigated. Comparisons have been made before and after the accident. Although there was only a very low level of contamination, the contamination rate of different species varied; on average, the Red Deer showed the highest activity (130 Bq/kg). The level of caesium contamination was mostly influenced by the permanent habitat of the animals. The main influence was due to regional, geographical and meteorological conditions. The influence of age or sex could not be determined. The contamination rate was shown to decrease with time.     

Regional calibration of erosion radiotracers (210Pb and 137Cs): atmospheric fluxes to soils (northern Spain)

Inventories of radionuclides commonly used to study environmental processes, especially in erosion research, were determined in soil cores from two distant river basins in northern Spain. Results showed that 210Pb atmospheric fluxes correlate very well with mean annual rainfall across the region, and this is also the case for 137Cs inventories but only on the basin scale. Therefore we suggest that 210Pb is a better candidate as a radiotracer for soil erosion studies. In this region, the equation 210Pb flux (Bq m(-2) yr(-1)) = (0.19 +/- 0.02) x rainfall (mm yr(-1)) - (24 +/- 17) can be used as a calibration to estimate input 210Pb fluxes, a key parameter in soil erosion studies and models, when mean annual rainfall is known.     

面向21世纪老年人健康性居室环境的设计

二十一世纪,老龄化是我国的一个重要问题,老年人居室环境是一个热点话题,本文从室内设计原则、室内布置、室内装饰、家具等方面阐述如何做好老年人居室环境的健康性设计。     

Distribution and retention of 137Cs in sediments at the Hanford Site, Washington

137Cesium and other contaminants have leaked from single-shell storage tanks (SSTs) into coarse-textured, relatively unweathered unconsolidated sediments. Contaminated sediments were retrieved from beneath a leaky SST to investigate the distribution of adsorbed 137Cs+ across different sediment size fractions. All fractions contained mica (biotite, muscovite, vermiculatized biotite), quartz, and plagioclase along with smectite and kaolinite in the clay-size fraction. A phosphor-plate autoradiograph method was used to identify particular sediment particles responsible for retaining 137Cs+. The Cs-bearing particles were found to be individual mica flakes or agglomerated smectite, mica, quartz, and plagioclase. Of these, only the micaceous component was capable of sorbing Cs+ strongly. Sorbed 137Cs+ could not be significantly removed from sediments by leaching with dithionite citrate buffer or KOH, but a fraction of the sorbed 137Cs+ (5-22%) was desorbable with solutions containing an excess of Rb+. The small amount of 137Cs+ that might be mobilized by migrating fluids in the future would likely sorb to nearby micaceous clasts in downgradient sediments.     

食品中沙门菌PCR检测方法的建立

为建立食品中快速检测沙门菌的PCR方法。选取沙门菌属侵袭性抗原保守基因invA基因上的靶序列设计一对引物,选择最适Mg 浓度和退火温度,建立最适PCR反应体系,用2%琼脂糖,5μl反应产物(包括EB),100V,40min进行电泳,显像。用该引物对已经传统方法鉴定的22种77株沙门菌和24种24株非沙门菌进行特异性检测,并对人工污染的食品进行检测条件的研究。Mg 浓度和退火温度对该反应体系的影响较小,稳定性较好;经传统方法鉴定的22种77株沙门菌和24种24株非沙门菌验证了该检验方法具有很好的特异性;该检测方法可以在19h内检出含有沙门菌102CFUg的食品(火腿肠、鸡蛋、散装肉馅)。与传统方法比较,该方法快速、敏感、特异,能在较短的时间内对大量样品同时进行检测,适用于食品中沙门菌的快速、敏感、特异检测。     

HPLC Analysis of Phytic Acid in Selected Foods and Biological Samples

A rapid high-performance chromatographic (HPLC) method for phytic acid was developed and applied to wheat and rice bran, beans and feces. The method gives more reproducible results than those obtained by other methods tested and is more rapid than methods using ferric chloride precipitation. The phytic acid contents of bran, bean and feces samples were determined by three methods, including the new HPLC method. For most samples, the methods gave significantly different results.     

A Method for Measurement of the Transient Response of Semisolid Foods Under Steady Shear

A Weissenberg Rheogoniometer was interfaced to a microcomputer for data acquisition, filtering, and processing. Reproducible and accurate measurements were made during steady shear of the transient stress response, characteristic of time-dependent semisolid foods. Differences between the initial flow process were found between two brands of commercial mayonnaise and one of spoonable salad dressing.