HACCP-based procedures in Germany and Poland

A study concerning HACCP implementation was conducted in 86 German and 66 Polish food enterprises. The questions asked in this study addressed HACCP implementation according to the 12 steps defined by Codex Alimentarius Commission. Some deficiencies were identified. As the results show, the specification of biological hazards is frequently not sufficient to provide suitable guidance mechanisms, and to monitor the limits, and therefore, they are not in compliance with Codex Alimentarius and Regulation (EC) No 852/2004. Furthermore, a lack of consistence in defining terms (e.g. CP) leads to their diverging application in practice. Overall, the HACCP implementation in Poland was found to comply somewhat better with the Codex Alimentarius principles and Regulation (EC) No 852/2004 than in Germany.     

Prolonged hydrogen production by Nostoc in photobioreactor and multi-stage use of the biological waste for column biosorption of some dyes and metals

Hydrogen production by Nostoc linckia was studied using both free and alginate immobilized biomass of the cyanobacterium in separate lab-scale photobioreactors (PBRs). Hydrogen production rates improved significantly when immobilized cyanobacterial biomass was used in PBR and the production continued up to 25 days by maintaining required anoxic conditions and carbohydrate supplement. Average hydrogen production rate over 25 days was 132 μmolH₂/h/mg Chl a. The biological waste from the PBRs was utilized for sequestration of two toxic heavy metals (chromium and cobalt) and carcinogenic dyes (Reactive Red 198 and Crystal Violet) from aqueous solutions in packed-bed column. From the PBR containing free N. linckia cells, the spent biomass was collected after 7 d, dried and immobilized in alginate matrix, and used as a biosorbent for optimizing bed height and flow rate of the column. Breakthrough capacity of the packed-bed column was determined and breakthrough curves were analyzed using BDST model. Three PBRs containing immobilized cyanobacterial biomass were run for 5, 15 and 25 days, and the biological waste collected at the end of the operation was used for biosorption studies under optimized conditions (bed height, 25 cm; flow rate, 3 mL/min). Biosorption efficiency of the waste biomass was found to be influenced by the operation time of the hydrogen photobioreactor.     

保健食品促进排铅模型小鼠饮水染铅剂量及检测指标的探讨

为探讨保健食品促进排铅作用动物模型饮水染毒的适宜剂量，给小鼠自由饮用Pb^2 浓度为163．9、546．2、l638．7mg／L的醋酸铅溶液30d，每周记录饮用量，周末称重，估算实际铅摄入剂量。实验末取血、肝、脑、肾、股骨，石墨炉原子吸收分光光度法测定全血和组织铅含量。结果显示，163．9、546．2、l638，7mg Pb^2 ／L剂量组小鼠实际铅摄入剂量分别为27．9、86．6、169．4mg／kg BW，546．2、1638．7mg Pb^2 ／L剂量组小鼠体重增长较对照组显著减少，食物利用率也明显降低；各剂量组小鼠全血、肝、肾、股骨铅及546．2、1638．7mg Pb^2 ／L剂量组小鼠脑铅含量显著升高。建议以546．2mg Pb^2 ／L作为保健食品促进排铅作用饮水染毒的造模剂量；除骨铅外，建议增测肾脏、脑组织内的铅、锌、铜含量及骨骼内的钙含量。     

酵母生物制剂对果蔬采后病害形成的影响

近年来的研究表明,酵母菌株的生物制剂对果蔬采后病害具有良好的抑制作用,如用其替代杀菌剂可减少农药使用量,降低产品的农药残留,保护生态环境,保证食品安全。本文介绍了酵母对病原微生物的拮抗作用机制,并对影响拮抗剂使用效果的一些重要因素,以及对如何提高拮抗效果的措施进行了深入的讨论。该领域具有很好的研究和应用前景。     

大豆异黄酮生理活性的研究进展——(1)大豆异黄酮的代谢及雌激素特性

大豆尤其是大豆胚轴富含有益于人类健康的大豆异黄酮。人体内的两种专一肠道细菌能将大豆异黄酮中的大豆苷和染料木苷代谢为相应的糖苷配基大豆黄素和染料木黄酮。马雌酚是大豆黄素在肠内细菌作用下的代谢产物,具有比大豆异黄酮更高的生理活性,但是并非在所有摄取大豆异黄酮的健康成年人体内都能产生马雌酚,马雌酚的产生与体内是否存在某些特定的肠内菌丛有关。大豆蛋白能影响肠内菌丛的构成,进而提高大豆异黄酮的生物利用率。大豆异黄酮是一类选择性雌激素受体调节剂,具有雌激素和抗雌激素的双重活性,可安全有效地用于预防和治疗妇女更年期综合症。     

An adaptive RNA genetic algorithm for modeling of proton exchange membrane fuel cells

The accurate mathematical model is the key issue to simulation and design of the fuel cell power systems. Aiming at estimating the proton exchange membrane fuel cell (PEMFC) model parameters, an adaptive RNA genetic algorithm (ARNA-GA) which is inspired by the mechanism of biological RNA is proposed. The ARNA-GA uses the RNA strands to represent the potential solutions and new genetic operators are designed for improving the global searching ability. In order to maintain the population diversity and avoid premature convergence, on the basis of the dissimilarity coefficient, the adaptive genetic strategy that allows the algorithm dynamically select crossover operation or mutation operation to execute is proposed. Numerical experiments have been conducted on some benchmark functions with high dimensions. The results indicate that ARNA-GA has better search capability and a higher quality of solutions. Finally, the proposed approach has been applied for the parameter estimation of PEMFC model and the satisfactory results are reached.     

不同填料曝气生物滤池启动挂膜试验研究

不同填料曝气生物滤池在相同条件下进行挂膜试验。进水流向为上流式,挂膜方式为复合接种挂膜,即先用活性污泥闷曝接种,然后逐步提高进水流速,直到滤料表面形成稳定的生物膜。结果表明:33 d后挂膜成功,在温度为16～24℃,水力停留时间(HRT)为1 h,DO为6 mg/L的情况下,陶粒BAF对CODMn和NH3—N的去除率分别为23%和80%;沸石BAF的去除率分别为27%和84%;组合填料BAF去除效果最好,去除率分别为32%和92%。     

神经网络模型在预测BAF出水水质中的应用

采用BP神经网络模型对沈阳仙女河污水处理厂曝气生物滤池出水水质进行预测,将运行数据分为训练样本和测试样本,对神经网络模型的预测值和实测值进行t检验发现两者之间无显著差异,结果表明,神经网络模型可以对BAF处理系统的出水水质预测及运行管理提供参考。     

塔中地区不同Mango轻烃参数原油的地球化学特征

塔中地区存在两种Ｋ１值原油,塔中北斜坡正常Ｋ１值原油和中央断垒带异常高Ｋ１值原油。研究表明不同Ｋ１值原油中饱和烃生物标志化合物组合特征相似,但芳烃尤其是二苯并噻吩系列化合物绝对含量和内组成则差异迥然。异常高Ｋ１值原油中二苯并噻吩系列化合物占总芳烃含量的４５％以上,其中甲基二苯并噻吩与三甲基二苯并噻吩比值大于１;相反,正常Ｋ１值原油中二苯并噻吩系列化合物占总芳烃的含量优于２５％,而甲基二苯并噻吩与三     

凝析油炼油污水处理设计及运行

根据阿尔及利亚凝析油项目产生污水的水质指标、排放标准要求及当地的具体条件,制定合理的污水处理工艺流程,实际运行处理后水质达到排放标准的要求。同时污水处理设施采用集中框架布置,节省了工程投资和占地。