Occurrence and characteristics of Vibrio vulnificus in retail marine shrimp in China

Vibrio vulnificus is a gram-negative bacterium that naturally occurs in estuarine waters and marine environment. Consumption of seafood contaminated with V. vulnificus or exposure to the contaminated water causes septicemia, gastroenteritis or wound infections in humans. This study aimed at identifying the prevalence of V. vulnificus in shrimps in Chinese seafood market. From June to September 2009, 239 samples encompassing six shrimp species were collected from ten cities in China. To quantify the prevalence and the levels of V. vulnificus in shrimps, the most probable number (MPN) method was used combining with the polymerase chain reaction (PCR) which was used to classify the isolates by detecting V. vulnificus hemolysin gene (vvhA). One hundred and forty out of 239 samples were positive for V. vulnificus, with the geometric mean level at 153.3 MPN/g. The prevalence and levels of V. vulnificus in shrimps varied in different geographic areas, with the values for the samples in the South cities (179.6 MPN/g) remarkably higher than that in the North cities (7.6 MPN/g). In addition, we found that 61.7% (79/128) of the V. vulnificus positive samples contained C-type (Clinical) strains and 8 contained E-type (Environmental) strains. The antimicrobial susceptibility of the isolates to 12 antibiotics was tested as well. Most of the 169 isolates remained susceptible to the majority of antimicrobials tested, whereas some strains tend to be less sensitive to amikacin, ampicillin, tetracycline and gentamicin. In conclusion, V. vulnificus is commonly found in retail marine shrimp in Chinese seafood market, and most of the shrimp samples contained C-type strains, which may pose a potential threat to human health.     

食源性大肠杆菌噬菌体的分离及其特性分析

目的从污水样品中分离致病性大肠杆菌的烈性噬菌体,分析其生物学特性,为食品中致病性大肠杆菌的控制提供参考。方法以标准菌株Escherichia coli EPEC(CICC10664)为宿主菌,采用双层平板法,从扬州市各地污水中分离纯化噬菌体,通过透射电镜观察其形态、测定最佳感染复数、一步生长曲线、裂解镨及其对宿主菌生物被膜的影响。结果分离到一株肠致病性大肠杆菌烈性噬菌体,命名为Ec.P01,电镜观察其为肌尾噬菌体,直径约为80 nm,最佳感染复数为0.01,一步生长曲线显示其噬菌体Ec.P 01的平均裂解量为48 PFU/m L,潜伏期约为10 min,裂解期约为90 min,热稳定性较好,对宿主菌生物被膜的形成有明显的抑制作用。结论本研究分离到一株肠致病性大肠杆菌烈性噬菌体,为治疗大肠杆菌感染疾病和治理食品及其环境污染提供新的思路与方法。     

食品包装安全监管中的风险管理应用架构

开展了对食品包装产品的风险要素识别、风险分析和评估要点的建立、基于风险预警的检验监管措施等研究,并提出了具体建议,系统地阐述了风险管理在食品包装安全监管中的应用方法和实践模式。     

丝胶蛋白整理对氧化竹原织物抗皱性能的影响

针对竹原纤维织物在服用性能方面抗皱性较差的问题,首先采用高碘酸钠对竹原织物进行选择性氧化,再利用丝胶蛋白溶液对氧化竹原织物进行抗皱改性整理.测试了在不同氧化剂浓度以及不同丝胶蛋白溶液整理条件下竹原织物的急弹和缓弹折皱回复角,并对工艺条件进行了优化.整理结果表明:氧化竹原织物经丝胶蛋白溶液整理后抗皱性能得到了显著改善.最佳整理方案为:氧化剂NaIO4质量浓度4 g/L,丝胶蛋白溶液质量分数3%,处理温度50℃,处理时间2 h.     

离子色谱-电感耦合等离子体质谱法检测纺织品中六价铬

为破除国际贸易壁垒,保障民众健康,尝试建立具有更高灵敏度的检测纺织品萃取液中六价铬的方法。采用离子色谱 电感耦合等离子体质谱联用技术（IC-ICP-MS）,使用IonPac AG11阴离子交换色谱柱、NH₄NO₃淋洗液,结合梯度洗脱和碰撞反应池技术（CCT）,通过对照实验和同位素丰度比,对色谱图做了较为详细的分析与讨论。实验表明,本方法可以很好地分离溶液中的三价铬[Cr(Ⅲ)]和六价铬[Cr(Ⅵ)]。当进样量为100 μL时,对溶液中六价铬的检出限达到0.02 μg/L。本方法操作简便、灵敏度高,适用于检测纺织品中可萃取的六价铬。     

出口内涂罐包装的游离酚GC-MS法迁移分析

针对内涂环氧酚醛罐的出口食品包装产品,分析了国内外对材料中酚类等有害物迁移研究的差异.采用气相色谱质谱(GC-MS)技术,研究了内涂环氧酚醛罐中游离酚的定性定量分析检测,并通过模拟产品不同使用环境和条件,研究了游离酚向食品中的定向迁移特性.结果表明,所提方法不仅能检测出样品中的游离酚,背景干扰较少,还可对相应的游离酚化合物进行定性定量同步检测,且操作简单,灵敏度较高.该方法可为进一步补充和完善环氧酚醛内涂罐卫生标准的分析方法提供参考.     

轮胎填充油中8种多环芳烃的检测方法研究

建立了以二甲基亚砜溶剂液-液萃取、硅胶固相萃取柱净化进行样品前处理和气相色谱-质谱联用(GC-MS)相结合测定轮胎填充油中8种多环芳烃的分析方法。结果表明,二甲基亚砜液-液萃取的最佳温度为20~25 °C;8种多环芳烃在0.1~50 μg/mL的浓度范围内呈线性关系,线性相关系数均在0.998以上;方法检测限均为0.1 mg/kg;以10、100 μg两个水平进行加标回收,测得加标回收率在84.1 %~101.0 %之间,平行测定七次的相对标准偏差(RSD)在2.8 %~6.7 %之间,表明方法具有良好的回收率和精密度。该方法灵敏、准确、可靠,完全满足欧盟REACH法规对轮胎填充油中8种多环芳烃的限量要求,适用于轮胎填充油中多环芳烃的检测分析。     

Detecting 5-morpholino-3-amino-2-oxazolidone residue in food with label-free electrochemical impedimetric immunosensor

This paper reported a novel label-free electrochemical impedimetric immunosensor for sensitive detection of metabolite of furaltadone, 5-morpholino-3-amino-2-oxazolidone (denoted as AMOZ), based on monoclonal antibody against AMOZ (denoted as AMOZ–McAb) immobilized on gold electrode modified with 1,4-benzenedithiol and gold nanoparticle self-assembled layers. The sensitive steps of surface modification have been characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The immunoreaction between AMOZ and AMOZ–McAb directly triggered a signal via electrochemical impedance spectroscopy measurement. Under the optimized conditions, the relative change in impedance was proportional to the logarithmic value of AMOZ concentrations in the range of 1.0 to 1.0 × 10⁶ ng/mL (r = 0.9991) with the detection limit of 1.0 ng/mL. The advantages of the immunosensor are exhibited in its high sensitivity, wide linear range and better stability. The proposed impedimetric immunosensor was successfully applied to the determination of AMOZ in animal derived food with excellent recoveries.     

菜籽蛋白提取工艺的优化

以脱脂菜籽粕为原料,利用碱液提取菜籽粕中的蛋白质,采用Plackett Burman实验设计筛选出对蛋白提取具有显著影响的因子:pH(p=0.0348)、温度(p=0.0383)和提取次数(p=0.0090);采用响应曲面法优化,得到最佳工艺条件为:pH11、温度52℃和提取2次,同时建立了碱提蛋白的二次多项数学模型,对菜籽蛋白提取具有很好的预测作用。     

定量核磁共振技术及其在环保型轮胎助剂开发中的应用进展

介绍了欧盟REACH法规对轮胎中多环芳烃(PAHs)含量的限制及所规定的定量核磁共振(QNMR)检测方法对我国合成橡胶工业的影响,综述了QNMR技术的特点、测定PAHs的原理及主要影响参数,提出了QNMR技术在环保轮胎助剂开发中的应用方向。