Simultaneous determination of biogenic amines and estrogens in foodstuff by an improved HPLC method combining with fluorescence labeling

Biogenic amines (BA) and estrogens (ES) have attracted increasing attentions due to their significance on food safety and food quality. In this study, a novel HPLC-FLD method using ethyl-acridine-sulfonyl chloride (EAC) as fluorescence labeling reagent has been developed for simultaneous determination of BA and ES in food samples. The labeling conditions including labeling time, pH of borate buffers and amount of EAC were optimized. The simultaneous labeling of BA and ES can be finished in as little as 6 min. This method without complex pre-treatment offered the low LOD of 0.27–0.69 ng/mL. It was applied to analyze several food samples (beer, cheese, fish, sausage and shrimp), and showed excellent applicability.     

国标法和纸片法对食品中大肠菌群检测比较

介绍了用国标发酵法(下简称国标法)和快速检测纸片法(下简称纸片法)对进出口食品中大肠菌群的检测结果采集进出口冷冻饮品、果汁、淀粉、奶粉、乳清粉等各类食品268份,用国标法与纸片法进行了对比检测试验两种方法对大肠菌群检测结果相符的260份,符合率97.1％;两种方法对268份样品检验的合格率相同,合格符合率100％纸片法简便、快速,能代替国标法准确测定各类食品中的大肠菌群     

Pulsed field gel electrophoresis typing of human and retail foodstuff Campylobacters: an Irish perspective

Campylobacter enteritis is a zoonosis, an infectious disease transmissible under normal conditions from vertebrate animals to man, presenting a major global public health burden. In this study, Pulsed Field Gel Electrophoresis (PFGE) was employed to identify common genotypes in a collection of 600 Campylobacter isolates in order to investigate if profiles obtained from retail samples of foodstuffs matched genotypes causing illness in the community in Ireland. The Campylobacters were isolated from retail foodstuffs, and cases of gastroenteritis, over the same 20-month period in three population centres in Ireland. The major observation made was of a high level of PFGE-genotype heterogeneity; 236 SmaI discrete genotypes were found in 507 strains successfully analysed. Analysis of the PFGE profiles revealed 22 common profiles amongst food isolates and those causing enteritis in humans. These cojoint PFGE genotypes indicate that 56 (38%) of the human clinical isolates are genetically related to 129 (36%) of the food isolates. The identification of these recurrent PFGE types, in the sampled Campylobacter coli and Campylobacter jejuni populations, indicates that a high proportion of Campylobacter isolates found in foods of animal origin also occur in patients with symptoms of enteritis. This data adds weight to the epidemiological hypothesis that a high proportion of human Campylobacter cases are contracted via the handling and consumption of contaminated foodstuffs, in particular poultry.     

DRYING WITH SUPERHEATED STEAM

The principle of drying with superheated steam is known for a long time already, and different designs have been worked out and partly realised. The principle of the steam drying described in this paper starts with superheated steam that is blown on to the products to be dried. The superheated steam transfers its sensible heat to the product and the water to be evaporated. The superheated steam acts both as heat source and as drying medium to take away the evaporated water. The majority of the superheated steam has to be recirculated and reheated. The excess steam from this process, corresponding to the evaporated water, can be used elsewhere in the process or plant, thus making an efficient energy recovery possible. Possible emissions from the drying process can be effectively removed by condensation. Drying by means of superheated steam impingement is one of the possible designs that are in progress now for the paper industry. Work is going on with respect to this type of drying for other materials, especially foodstuffs. At present experimental research at the laboratory steam dryer of TNO-MEP is carried out for vegetables, fries, herbs, cacao nuts, wheat, flour, etc. Besides the energy savings and environmental benefits, the oxygen free steam atmosphere and the higher product temperatures in the dryer appear to have positive effects on the product qualities. For foodstuffs combinations of steam drying with blanching, pasteurisation, sterilisation, etc. are possible and make the steam drying very attractive for food producers. Modelling of the processes in foodstuffs during steam drying is established, both on macro and micro scale. In this paper examples and results of research on steam drying for specific products will be presented.     

真空预冷装置的研究

简要介绍真空预冷的工作原理与特点及其装置的结构设计。顺应了食品趋向高营养保鲜的潮流，满足了人们对食用天然食品的需求。     

Development and validation of a grouping method for pesticides analysed in foodstuffs

The cost effective monitoring of hundreds of pesticide residues in foodstuffs of vegetable origin involves the definition of groups of analytes associated with homogeneous performance parameters of the used analytical method. The performance of the analytical method only needs to be tested on a daily base for some of these group’s compounds. This work proposes a strategy for defining groups of compounds with homogeneous physical–chemical properties based on the evaluation of the similarity of the multivariate pattern of five of these properties namely: molar mass, melting point, vapour pressure at 20 °C, n-octanol–water partition coefficient and solubility in water at 20 or 25 °C. Three independent and competing multivariate analysis tools, namely Principal Component Analysis, Hierarchical Clustering and K-Mean Clustering were used. This strategy was successfully used to group 100 pesticides into nine clusters, with 1–40 pesticides, represented by a compound with within group average properties. The developed grouping method was validated using physical–chemical data from other references or compounds and produced groups consistent with the performance of the studied determination of pesticide residues in dried red bean. The mean analyte recoveries of groups with larger dimension are statistically different for a confidence level of 95%. The within group coefficients of variance of mean analyte recoveries of larger groups ranged from 6.7% to 8.5%. This grouping method can reduce the number of recovery tests performed for the validation of the analytical method or test quality control.     

我国食品中的^237Np含量水平

采用化学分离、电沉积制源和α谱测量联合分析方法对我国主要食品中~(237)Np放射性含量进行了分析调查。调查结果表明,我国主要食品中~(237)Np含量水平为10~(-4)-10~(-3)Bq·kg~(-1)。     

铁路冷藏运输主要技术条件的研究

铁路冷藏运输作为我围食品冷藏链的重要环节,对食品安余供应和流通质量起着重要作用。铁路现有冷藏运输条件标准较低,不能满足当今市场供应要求,有必要依食品贮运要求进行更新提高,以有效提高铁路冷藏运输水平,提高食品质量及安全性。在充分研究借鉴国内外相关食乩标准的基础卜,结合我围国情、路情和易腐产品市场发展需求等情况,全面系统地对铁路冷藏运输技术条件进行了更新修订,补充完善了关键质量指标,严格了各项运输指标。文章介绍了其中的关键技术指标的确定过秤。     

Potential migration of Diisopropyl naphthalenes from recycled paperboard packaging into dry foods

The results of a study of the potential migration of diisopropyl naphthalenes (DIPN) from recycled paperboard packaging into some types of dry solid foodstuffs are reported. Paperboard diskettes containing different DIPN concentrations were prepared and put into contact with four types of dry solid foodstuffs, having high specific surface areas and different lipid contents. At regular intervals the DIPN content in the foods was determined. Two migration mechanisms have been proposed and verified. The first one relates to the direct contact existing between paperboard and foodstuff. The second one refers to the indirect contact between paperboard and food, controlled by an air space created above the paperboard into which the DIPN has diffused. Both mechanisms occurred and the migration depended on different factors: the contact time, the characteristics of the foodstuffs and the DIPN content in the cellulose-based matrix. However, only very low levels of contamination in the foodstuffs occurred in migration. As a consequence, this report also considers possible limitations which could be applied to the content of carbonless copy paper in packaging paperboard formulations.     

微柱液相色谱法同时检测食品中苯甲酸和山梨酸

通过自构建的微柱液相色谱系统上色谱条件的优化,建立了一种同时检测食品中苯甲酸和山梨酸的新方法。食品中苯甲酸和山梨酸经提取后,6分钟内达到基线分离,与常规高效液相色谱法相比,分析时间缩短,流动相消耗减少。在1～25 mg/L浓度范围内线性关系良好,相关系数分别为0.9999和0.9997。苯甲酸和山梨酸的回收率均在94.7%～103.1%之间,三次平行加标回收率测试,相对标准偏差分别为1.12%和1.29%。该方法稳定性好,回收率高,能快速、准确的检测食品中苯甲酸和山梨酸。