一例孕产妇单核细胞增生李斯特菌感染的溯源调查及发病机制探讨

目的 针对一例孕产妇李斯特菌病开展病例调查和溯源分析,探讨感染来源和单增李斯特菌病的发病机制,为防控李斯特菌病提供依据。方法 开展现场流行病学调查,收集病例信息,采集病例血液标本、家庭冰箱内食品及厨房环境样本、家庭附近农贸市场的食品样本,针对不同来源样本中的单增李斯特菌进行检测。结果 病例经常食用从农贸市场购买的中式凉拌菜（5～7次/周）,在家自制或二次加工中式凉拌菜。其家庭冰箱冷藏室储存食物生熟不分,且生食水果在冰箱中出现腐烂现象。厨房的两块菜板生熟不分、清洗消毒不及时,厨房操作面存在交叉污染。检测结果显示,11份样本中共分离出3株单增李斯特菌,1株来自该病例的血液标本,2株来自厨房冰箱内食品涂抹和菜板涂抹。提示该病例由于食用污染食品导致感染并通过胎盘屏障感染胎儿。结论 本起事件是丰台区首次在食品和环境中尝试溯源单增李斯特菌病的感染来源。病例家庭冰箱内生肉和胡萝卜、厨房环境涂抹样本中均检出单增李斯特菌,明确了食品与环境交叉污染导致病例单增李斯特菌感染发病;医院的早期识别及处置是避免新生儿不良结局出现的重要保障。     

Determination of Five Alkaloids of Pericarpium Papaveris in Hot Pot Broth Using Ultra-Performance Liquid Chromatography Coupled to Triple Quadruple Mass Spectrometry

Simultaneous determination of five alkaloids (morphine, codeine, noscapine, thebaine, and papaverine) of pericarpium papaveris in hot pot broth was established by ultra-performance liquid chromatography (UPLC) coupled to triple quadruple mass spectrometry (QqQ-MS). Water containing 0.1 mol/L hydrochloric acid was used as extraction solution and petroleum ether were used for fat removal. Then, the water-phase extracts were purified by an Oasis MCX cartridge. After separation by a BEH C18 (50?×?2.1 mm, 1.7 μm) column, five alkaloids were detected by mass spectrometry in the positive electrospray ionization with multiple reaction monitoring (MRM). The linear ranges were 0.1–10.0 μg/kg for morphine, codeine, and thebaine, as well as 0.01–1.0 μg/kg for papaverine and noscapine, respectively. The limits of quantification (LOQs) for morphine, codeine, and thebaine were 0.1 μg/kg and for papaverine and noscapine were 0.01 μg/kg. Mean recoveries at three spiked concentrations for the objectives were varied from 72.1 % to 124 %. The method was employed in real samples and demonstrated its rapidness and high sensibility.     

Determination of Arsenic Species in Edible Mushrooms by High-Performance Liquid Chromatography Coupled to Inductively Coupled Plasma Mass Spectrometry

The content of total arsenic was determined by inductively coupled plasma mass spectrometry after microwave digestion. The results showed that the content of total arsenic was ranged from 0.04 to 212.3 mg kg^?1 in the test edible mushrooms. The content of total arsenic in eight test samples was greater than 0.5 mg kg^?1. However, the toxicity of arsenic is closely related to the chemical form. Therefore, the determination of arsenobetaine, arsenocholine, dimethylarsinic acid, monomethylarsonic acid, arsenite, and arsenate in edible mushrooms was performed on an ion exchange chromatography column (Dionex IonPac AS19) with inductively coupled plasma mass spectrometry as a detector. When water and 50 mM (NH₄)₂CO₃ (pH = 9.7) were worked as a mobile phase, the six arsenic species could be well separated in 20 min. Ultrapure water was selected as extraction solvent for the validation of ultrasound-assisted extraction method due to its advantage of simple, cheap, and high extraction efficiency. Under optimum conditions, the limits of detection were <2.5 μg kg^?1 of the test arsenic species for arsenic, and the recoveries of all six arsenic species were >91.0 % with the relative standard deviation of <5.5 %. The method was applied to 19 different mushroom samples. The results indicated that the total content of arsenic species was basically identical with the content of total arsenic. And arsenobetaine was proved to be the main arsenic species in the test Lentinus edodes-2 sample.     

Simultaneous Determination of 11 Food Additives by Micellar Electrokinetic Capillary Chromatography

A micellar electrokinetic chromatographic (MEKC) method was developed for simultaneous determination of 11 food additives which are commonly used in beverage, yogurt, and candied fruit samples. An uncoated fused-silica capillary with 50 μm i.d. and 70 cm total length (effective length: 60 cm) was used for the separation. The separation buffer consisted of 20 mmol/L sodium tetraborate, 42 mmol/L boric acid (pH 8.83), and 100 mmol/L sodium deoxycholate. The separation voltage was 23 kV, and the detection wavelength was 214 nm. The limits of detection were in the ranges of 0.25 to 2.5 mg/L. The corrected peak areas (Ac) and the concentrations of the 11 additives showed linear relationships within the ranges of 0.6–400 mg/L with linear correlation coefficients (r) above 0.99. The recoveries ranging from 81.6 to 115.0 % with relative standard deviations (RSDs) all lower than 5 % were obtained, which demonstrated the accuracy of the proposed method. A Food Analysis Performance Assessment Scheme (FAPAS®) proficiency test sample was analyzed. The results showed that the current method with simple sample pretreatment could meet the needs for routine analysis of the 11 additives in beverage, yogurt, and candied fruit samples.     

Influence of pilot scale in pack pasteurization and sterilization treatments on nutritional and textural characteristics of carrot pieces

The current work presents a pilot scale study in which the effect of in pack thermal preservation processes in a retort system on particular carrot quality aspects, more specifically nutritional and textural characteristics, was investigated. Pasteurization as well as sterilization processes with different intensities were included. The carrot hardness, analyzed by a compression test, and the β-carotene bio-accessibility, analyzed by an in vitro digestion method, were the main quality markers. As a main conclusion, it can be stated that the results of this pilot scale study are a good validation of results obtained during previous laboratory scale experiments on carrot nutritional and textural characteristics. The processes applied in this study only resulted in limited conversion of all-trans-β-carotene to its cis-isomers. Furthermore, it was shown that intense thermal processing is required to observe a significant increase in the β-carotene bio-accessibility. However, this was accompanied with a clear degradation of the hardness. When thermal processing was preceded by low temperature blanching, a technique to improve texture retention of thermally processed plant-based foods, a lower β-carotene bio-accessibility was observed. Both observations clearly illustrated the inverse correlation between textural and nutritional characteristics of (processed) carrots. Statistical analyses confirmed the trends observed. For process design, the choice of the process intensity was identified to be crucial: the required product safety needs to be achieved, while still reaching an acceptable structural and nutritional quality. Exploring strategies to enhance the β-carotene bio-accessibility while ensuring an acceptable carrot texture can therefore be useful.     

毛细管电泳法测定甘蔗中3-硝基丙酸

目的建立甘蔗中3-硝基丙酸的毛细管电泳分析方法。方法粉碎后的甘蔗经样品提取液提取,离心除杂后,在228 nm波长处用毛细管电泳法检测。结果在优化的实验条件下,3-硝基丙酸的质量浓度在1.0～100.0 mg/L范围内与其对应的校正峰面积呈良好线性关系(r=0.9997)。方法检出限(S/N=3)为0.3 mg/L,定量限(S/N=10)为1.0 mg/L。在10.0、50.0 mg/L两个添加水平下,方法的回收率分别为95.2%和103.9%,相对标准偏差(n=5)分别为2.2%和1.3%。结论本方法简便、灵敏、准确,可用于甘蔗中3-硝基丙酸的测定。     

基于北京市某城区和张家口崇礼地区食品调查数据的镉暴露评估

目的 预先评估北京冬奥会周边地区主要食品中镉（Cd）暴露水平及可能存在的健康风险,为2022北京冬奥会及周边居民食品安全风险评估和安全保障提供部分参考依据。方法 在对镉进行危害评估和限量标准分析的基础上,采用2019—2020年北京市某城区和张家口崇礼地区现场采样调查数据,结合2018年北京市主要食品消费量调查数据,运用点评估的方法,对镉的膳食暴露风险进行评估。结果 采集的各类食品中镉总体平均含量为0.010 6 mg/kg,总体超标率为0.47%。北京市居民通过摄入主要食品的镉平均暴露量为5.92μg/（kg·BW·m）,占粮农组织/世界卫生组织食品添加剂联合专家委员会（JECFA）推荐的可耐受月摄入量（PTMI）25μg/kg·BW的23.66%,且粮谷和蔬菜类食品是本次调查膳食镉的主要暴露来源。按其现行GB 2762—2017《食品安全国家标准食品中污染物限量》中镉的限量标准,除了这两类食品外,其余食品中的镉理论暴露量均未超过PTMI。蔬菜类和粮谷类的推算关注阈值（LOC）为0.172和0.199 mg/kg,略小于国标规定的最大限量值。结论 冬奥会及北京市居民主要食品镉暴露预期...     

Occurrence of mycotoxins in fruit juices and wine

Mycotoxins are produced by secondary metabolism of various fungal species. Numerous studies were performed on the occurrence of the mycotoxins in raw commodities and foodstuffs. These studies were carried out on account of their high toxicity and the possible risk they can present for the health of the consumers. The purpose of this paper is to review the occurrence of mycotoxins in fruit juices and wine.     

A Simple and Rapid Method for Determination of Patulin in Juice by High Performance Liquid Chromatography Tandem Mass Spectrometry

A simple and rapid method was developed for analysis of patulin in juice using ultra performance liquid chromatography coupled with tandem mass spectrometry. The samples were purified by an Oasis MAX 96-Well Plate. Chromatographic separation was performed on an ACQUITY UPLC® HSS T3 column with gradient elution using acetonitrile and water as mobile phase. Analytes was quantified by external calibration curves over the ranges of 0.50–50 μg/L, with correlation coefficients > 0.9986. The LOD and LOQ in juice sample were 0.30 and 1.0 μg/L, respectively. Recoveries of the method (spiked at levels of 1, 5, 25 and 50 μg/L) ranged from 91.6% to 95.7%, while intraday and interday relative standard deviations were 6.87–11.0% and 6.53–11.6%, respectively.