A reliable and sensitive time-resolved fluorescent immunochromatographic assay (TRFICA) for ochratoxin A in agro-products

Immunochromatographic assays (ICAs) are considered as a suitable diagnostic tool for the detection of mycotoxins. Mycotoxins and especially, ochratoxin A are analytes with more demanding sensitivity requirements. To enhance the sensitivity of current immunochromatographic assays for ochratoxin A (OTA), a novel sensitive ICA was developed in this study. In the assay, microspheres enclosing fluorescent europium (III) [Eu(III)] nanoparticles (EuNPs) were used as a label for OTA monoclonal antibody (OTA-mAb) conjugation. Accordingly, assay was called time-resolved fluorescent immunochromatographic assay (TRFICA). The test strip was composed of three parts: a sample pad, nitrocellulose membrane and an absorbent pad. As for detection, a proper concentration of conjugated microspheres was pipetted into the microtube and sample extract was added to it. Then the strip was inserted into the tube and the fluid flow along the strip. The TRFICA results were obtained in 8 min and read by a portable TRFICA strip reader. The established method allows quantitative determination of OTA with limit of detection as low as 1.0 μg kg⁻¹ in the samples. For validation, spiked samples including wheat, maize, soybean and rice were respectively assayed by TRFICA and a standard high performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD), and good agreement of results was obtained between two methods.     

2015-2019年江西省毒蕈中毒病例流行病学特征分析

目的 分析江西省毒蕈中毒病例的流行病学特征,为毒蕈中毒科学防控提供参考依据.方法 通过"食源性疾病监测报告系统"和"食源性疾病暴发监测系统"查询2015-2019年江西省毒蕈中毒病例,对其流行病学特征进行描述性分析.结果 2015-2019年江西省共报告毒蕈中毒病例1 354例,年均报告发病率为0.59/10万,病死率...     

江西省首起误食残托鹅膏有环变种毒蘑菇中毒事件调查与鉴定

目的 调查江西省2019年5月一起误食有毒蘑菇引起的中毒事件,并鉴定引起中毒的有毒蘑菇种类。方法 收集中毒事件的流行病学相关资料进行初步判断,对收集的蘑菇样品进行形态学和分子生物学鉴定。结果 流行病学调查发现患者均食用了自行采摘并煮汤的蘑菇,食量不等,平均潜伏期为2.5 h,出现头晕、恶心、呕吐、四肢麻木等症状,经形态学、分子生物学比对鉴定为残托鹅膏有环变种。结论 本事件为江西省报道的首起因误食残托鹅膏有环变种引起的毒蘑菇中毒事件,结合流行病学、形态学、分子生物学等方法可以鉴定引起毒蘑菇事件的蘑菇种类,提示江西省毒蘑菇中毒形势依然严峻,相关部门应加强防控。     

蜂胶提取物对诺如病毒的体外抑制作用研究

为研究蜂胶提取物对人源诺如病毒的体外抑制作用,采用小鼠诺如病毒和噬菌体MS2病毒为替代病毒,研究蜂胶水提物和醇提物随浓度及时间变化对小鼠诺如病毒和噬菌体MS2病毒的抑制作用及其机制.浓度相关性实验表明:随着蜂胶醇提物浓度增加,小鼠诺如病毒和MS2病毒滴度呈显著下降趋势,当醇提物质量浓度达到500μg/mL时,小鼠诺如病...     

Cement hydration and durability of low sulfide tailings-based renders: A case study in Moroccan constructions

Appropriate tailings management is one of the main requisites for sustainable development in the mining industry. This research study aims to assess the use of low sulfide or sulfide free tailings (LST) as aggregates for rendering mortars, focusing on their cement hydration and durability. An authentic case study in Moroccan constructions is additionally used to assess long term behavior of LST-based renders in actual field conditions. To address such needs, renders sampled from wall constructions and laboratory-made specimens were firstly characterized by means of thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRD), scanning electron microscopy investigation (SEM) and mercury intrusion porosimetry (MIP). Renders were then exposed to standard detrimental agents (moisture, sulfate water and acid rain) to assess their long term behavior. Experimental results confirmed that LST-based renders seem to involve different cement hydration processes, which lead to larger pore size distribution and lower CSH and portlandite content. These observations significantly influence their susceptibility to cracking and sulfate attack resistance.     

基于dsDNA-CuNCs的荧光ELISA检测牛奶中的E.coli O157:H7

目的:建立了一种灵敏检测牛奶中大肠杆菌O157:H7的新型荧光酶联免疫吸附方法。方法:以碱性磷酸酶水解焦磷酸盐-Cu²⁺配位复合物,释放出Cu²⁺形成铜纳米簇作为信号报告探针,通过对关键因素Cu²⁺浓度、焦磷酸盐浓度、DNA模板的浓度和长度进行优化。结果:在最优条件下,大肠杆菌O157:H7的菌数为5×10⁴～1×10⁸ CFU/mL时,与荧光信号值有较好的线性关系(R²=0.980 8),最低检出限为2.4×10⁴ CFU/mL。结论:该方法成功地应用于低脂牛奶和脱脂牛奶样本中大肠杆菌O157:H7的测定,平均回收率为92.2%～108.5%,相对标准偏差为4.9%～10.4%。     

2019年江西省3城市居民食物消费量调查结果与分析

目的 通过2019年江西省3城市居民食物消费量调查的研究,了解3城市居民膳食结构与营养素摄入情况。方法 采取多阶段分层整群随机抽样法,抽取南昌市新建区、吉安市井冈山市、九江市濂溪区共362户1 251人进行入户调查。膳食调查采用家庭称重记账法和非连续3 d 24 h回顾询问法相结合,收集食物消费量资料,分析每标准人日各类食物和营养素摄入状况。结果 2019年江西省3城市居民畜禽肉类、食用油和食用盐每标准人日摄入量分别为111.70、31.06、7.78 g;蔬菜类、水果类、蛋类及其制品、奶类及其制品每标准人日摄入量分别为240.53、47.97、27.91、26.31 g;谷薯类、水产品类每标准人日摄入量为398.30、42.95 g;蛋白质、脂肪、碳水化合物的供能比分别为14.68%、33.74%、51.50%。膳食钙、维生素A、维生素B1、维生素B2、维生素C每标准人日摄入量低于平均需要量的分别占89.74%、72.41%、89.04%、82.85%、60.21%;钠每标准人日摄入量超过适宜摄入量100%以上的占74.18%。结论 江西省3城市居民能量、蛋白质摄入量基本满足膳食要求...     

高效液相色谱法测定熟肉制品中苯甲酸、山梨酸、胭脂红和诱惑红含量

目的建立高效液相色谱法测定熟肉制品中食品防腐剂(苯甲酸和山梨酸)和色素(胭脂红和诱惑红)的分析方法。方法样品经组织捣碎、超声提取、过滤、定容,利用高效液相色谱法检测,甲醇水混合溶液作为流动相,二极管阵列检测器(photo-diode array,PDA)检测,苯甲酸和山梨酸的检测波长为230nm,胭脂红和诱惑红的检测波长为508nm。结果苯甲酸和山梨酸在0.05~0.30mg/mL,胭脂红和诱惑红在2.5~12.5μg/mL范围内,均具有良好的线性关系良好,相关系数r均0.9999。苯甲酸和山梨酸的最低检出限(limit of detection,LOD)范围为1.2~1.8 mg/kg,最低定量限(limit of quantification,LOQ)范围为3.6~5.4mg/kg;胭脂红和诱惑红的LOD范围为0.05~0.1mg/kg,LOQ范围为0.15~0.3 mg/kg。平均加标回收率为94.8%~96.9%,相对标准偏差(relative standard deviation,RSD)为2.4%~4.1%。100份熟肉制品样品中,5份有山梨酸检出,检出率为5.0%,检测结果范围为0.030~0.65g/kg;1份有胭脂红检出,检出率为1.0%,检测结果为0.0023g/kg;3份有诱惑红检出,检出率为3.0%,检测结果范围为0.0036~0.0083g/kg;苯甲酸在所有熟肉制品样品中均未检出。结论该方法灵敏度高,回收率高,检测限低,符合分析要求,适合检测熟肉制品中的苯甲酸、山梨酸、胭脂红和诱惑红。     

A systematic study on the interactions between carnosic acid and ethylpyrrolidine methacrylate–methyl methacrylate copolymer in supercritical media

In the present work, a systematic study on the interactions between carnosic acid (potent natural antioxidant from rosemary) and ethylpyrrolidine methacrylate–methyl methacrylate (EPyM/MMA) copolymer (synthesized in our laboratory) has been performed using different spectroscopic and thermogravimetric techniques. By comparing data obtained for the reference sample (carnosic acid + copolymer) with data of carnosic acid and copolymer alone, a polar interaction could be observed between the carboxylic acid group of carnosic acid with the tertiary amine of the EPyM/MMA copolymer, thus suggesting a charge-transfer complex of the carnosic acid molecules with the pyrrolidine nitrogen (conclusion supported by NMR, FT-IR and TGA data). In order to evaluate the possibility of using, in the near future, the copolymer as a selective stationary phase for preparative-SFC (supercritical fluid chromatography), the work has been completed by studying the remaining interactions, in the reference sample, once treated under several supercritical conditions. After the supercritical treatment (using CO₂ at different pressures and temperatures), depressurization takes place in the extraction cell and the samples remaining were characterized by ¹H NMR, TGA and FT-IR. From the results obtained, it can be inferred that interactions remain after supercritical treatment, thus allowing the design of selective polymers to be used in the purification of carnosic acid.     

2012—2021年江西省食源性疾病暴发事件流行病学特征分析

目的 分析2012—2021年江西省食源性疾病暴发事件的流行病学特征,为制定预防措施提供依据。方法 收集江西省2012—2021年食源性疾病暴发监测系统中报告的食源性疾病暴发事件资料,采用描述性流行病学方法对资料进行分析。结果 2012—2021年江西省共报告食源性疾病暴发事件1 285起,累计发病7 222人,死亡48人,病死率为0.66%（48/7 222）,各年度的病死率比较差异有统计学意义（P≤0.001）。10年间暴发事件数呈总体上升趋势,事件集中发生在5—9月份。在查明原因的768起暴发事件中,毒蘑菇引起的事件数和死亡人数最多,分别占50.78%（390/768）和93.75%（45/48）;微生物性因素引起的发病人数最多,占49.41%（2 266/4 586）,主要致病菌为沙门菌和副溶血性弧菌。家庭和餐饮服务场所是事件的主要发生场所,其中家庭发生的事件数和死亡人数最多,分别占64.75%（832/285）和95.83%（46/48）,主要致病因子为毒蘑菇;餐饮服务场所的发病人数最多,占51.77%（3 739/7 222）,主要致病因子为微生物性因素。结论 家庭是毒蘑菇死亡事件发生的主要场所;微生物性致病因子是餐饮服务场所和学校的主要致病因素。建议重点针对广大农村家庭开展食用野生蘑菇的危害性宣传,同时加大重点场所食品安全监督管理和健康教育力度,减少食源性疾病及死亡病例的发生。