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...     

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。     

食品重金属检验中样品处理和检验方法

食品安全问题一直是全世界最为关心的社会热点,尤其是含有重金属的食品,对人体健康危害极大,所以应该加强对食品重金属的检验.本文主要阐述了食品重金属检验中的样品处理方法和检验方法.一、食品重金属检验中样品的处理办法1.微波消解法.微波消除法是对食品重金属检验时使用的最为常见的样品处理方式之一,主要是依靠其热效应特性...     

食品中重金属检验样品处理和检验方法

食品安全历来都是民众比较关心的热点和焦点问题,如果食品中重金属含量超标,就会对人体造成伤害,所以必须加强对食品中重金属含量的检测.本文从食品中重金属对人体的危害人手,对食品中重金属检验样品的相关处理与检验方法进行了较为详细的论述.     

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。     

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.     

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.     

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.     

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.     

The Finite Element Method in Thermal Processing of Foods

A variational finite element approach using triangular simplex and 2nd order quadrilateral elements was employed to analyze several problem areas that are of practical importance in the thermal processing of conduction heating products: (1) A method was developed to calculate conversion factors for thermal process design applicable to glass jars filled with conduction heating products. (2) The overshooting of temperatures after steam-off was studied, indicating that not including the contribution of overshooting to sterilization values in process design, can lead to gross overprocessing. (3) A method of correcting sterilization values to account for harmonious fluctuations in retort temperature was developed. (4) The air cooling of cans by natural convection was analyzed.     

Pu and 137Cs in the Yangtze River estuary sediments: distribution and source identification

Pu isotopes and (137)Cs were analyzed using sector field ICP-MS and γ spectrometry, respectively, in surface sediment and core sediment samples from the Yangtze River estuary. (239+240)Pu activity and (240)Pu/(239)Pu atom ratios (>0.18) shows a generally increasing trend from land to sea and from north to south in the estuary. This spatial distribution pattern indicates that the Pacific Proving Grounds (PPG) source Pu transported by ocean currents was intensively scavenged into the suspended sediment under favorable conditions, and mixed with riverine sediment as the water circulated in the estuary. This process is the main control for the distribution of Pu in the estuary. Moreover, Pu is also an important indicator for monitoring the changes of environmental radioactivity in the estuary as the river basin is currently the site of extensive human activities and the sea level is rising because of global climate changes. For core sediment samples the maximum peak of (239+240)Pu activity was observed at a depth of 172 cm. The sedimentation rate was estimated on the basis of the Pu maximum deposition peak in 1963-1964 to be 4.1 cm/a. The contributions of the PPG close-in fallout Pu (44%) and the riverine Pu (45%) in Yangtze River estuary sediments are equally important for the total Pu deposition in the estuary, which challenges the current hypothesis that the riverine Pu input was the major source of Pu budget in this area.