Design considerations for heating or cooling of materials in vessels

Many food manufacturing processes employ agitated-type systems for heating or cooling of materials. In the thermal design of such systems the designer is faced with a considerable variety of design information and the data are often inconsistent. The deficiencies of existing design methodologies are discussed and the significance of mathematical representation of the physical system in facilitating valuable design information is highlighted. This will yield a more accurate design and hence a better control of the desired products in terms of quality and homogeneity.     

Using a quantitative risk assessment to mitigate risk of Listeria monocytogenes in ready-to-eat meats in Australia

To provide guidance to Australia meat processors a Monte Carlo simulation model that estimates the risk of listeriosis from processed meats in Australia [Ross, T., Rasmussen, S. R., Fazil, A., Paoli, G., & Sumner, J. (accepted for publication). Quantitative risk assessment of Listeria monocytogenes in ready-to-eat meats in Australia. International Journal of Food Microbiology] was used to assess the efficacy of alternative strategies proposed to reduce the risk of listeriosis from these products. The structure of the model enabled estimates of levels of Listeria monocytogenes throughout the predicted life of the product, and facilitated modelling of the proposed mitigations. Technological and economic constraints relevant to the Australian industry meant that, of the various proposed risk reduction strategies, the use of growth-rate retarding additives, such as salts of organic acids, were identified as the preferred risk mitigation option.     

A survey estimating the benefits of incorporating Listeria specific growth inhibitors in bulk luncheon meats to be sliced in retail delis

The rate of foodborne illness caused by Listeria monocytogenes continues to exceed the Healthy People 2020 goal of 0.2 cases per 100,000 persons. Listeria infections are primarily sporadic, most cases caused by eating contaminated, ready-to-eat (RTE) foods including luncheon meats sliced in retail delis which have been implicated as being responsible for as many as 83% of these illnesses. Listeria specific antimicrobials incorporated in RTE luncheon meats to be sliced in retail delis would lower the risk to consumers by as much as 96%, especially for high-risk consumers. Walmart and Sam's Club stores (Bentonville, AR), large retailers of RTE meats sliced in their delis, have required all their suppliers of bulk RTE meats which could support the growth of Listeria to include a verified inhibitor that will not allow an increase in L. monocytogenes of more than 1 log during the intended shelf-life and storage of the product. We surveyed these suppliers and determined that six of 15 suppliers had not added inhibitors to their bulk luncheon meat for Walmart prior to the 2010 requirement. One supplier reported using inhibitors in 60% of their products prior to Walmart's mandate and now uses Listeria specific inhibitors in 100% of the bulk deli meats it produces, regardless of customer. Three of the five manufacturers who needed to reformulate their products reported additional benefits: the Listeria specific antimicrobials extended their products' shelf life, improved food safety and provided better protection for their customers.     

Efficacy of ozone to reduce microbial populations in date fruits

Ozone is strong oxidant and potent disinfecting agent. There are numerous application areas of ozone in food industry such as sanitation of food plant equipments, surface hygiene and reuse of waste water. While the application of ozone for dried fruits disinfection and for fresh fruits and vegetables microflora destruction has been studied extensively, relatively little information is available on the potential of ozone to reduce microbial populations in date fruits. In this study, ozone was applied in gas form at three concentrations (1, 3, and 5 ppm) for four different periods (15, 30, 45 and 60 min) on Iranian date fruits and the reduction in the total bacterial count, Coliform, Staphylococcus aureus as well as yeast/mold counts were examined. The promising results indicated the efficacy of ozone to reduce the microbial populations in date fruits. Escherichia coli and S. aureus were not found on cultured plates inoculated with the treated samples after treatment with 5 ppm (p < 0.05) in 60 min. The method of ozone generation, type of application, as well as the optimal exposure time and concentration of ozone as an antimicrobial agent in date fruit is mentioned in detail.     

原位老化-微波加热合成A型分子筛膜及其应用

在管状基膜上采用原位老化-微波加热法合成出厚度为3μm的新型A型分子筛膜。X射线衍射和扫描电子显微镜分析表明,基膜上覆盖着一层致密的、连续的分子筛膜。利用该分子筛膜渗透汽化分离乙二醇质量分数为15%的乙二醇水溶液,在120℃时,渗透通量达到10.06 kg/(m2.h),分离系数大于10000。     

渤海SZ36-1水驱油田营养凝胶辅助微生物驱油技术

根据渤海SZ36-1油田H区块水驱油藏条件、水质及基础菌群特征,为提高微生物驱油效果,采用室内实验方法筛选了营养凝胶类型,并评价了其性能和配伍性。采用岩心驱替实验和数值模拟方法,优化了营养凝胶和微生物驱剂段塞组合和注入体积,结果表明,营养凝胶辅助微生物驱油效果最好,营养凝胶可以增大微生物驱剂在油藏中的滞留时间,同时产生营养成分缓释作用,激活油藏深部微生物菌群。     

Performance of conventional histochemical methods relative to a novel immunolabeling technique in assessing degree of degradation in comminuted chicken meat

The potential of a novel immunohistochemical method detecting the muscle protein meromyosin and the basement membrane protein laminin to objectively and accurately determine the degree of degradation of muscle tissue in comminuted chicken meat was investigated in comparison to three different conventional methods, two slightly different toluidine blue (TB) staining procedures and a haematoxylin-eosin (HE) staining. All samples were evaluated for degree of muscle degradation, one method by image analysis system and three by visual assessment of degree of degradation. Analyses were carried out on reference samples consisting of mixtures of emulsified and minced meat in steps of 10%. The immunohistochemical approach (LAM) showed better selectivity and good image quality. The correlation (R) between the amount of minced meat in mixtures and degree of degradation were higher and consistent by this approach (0.94 compared with 0.62, 0.61, and 0.85 for thigh muscles by LAM, HE, TB-Max Rubner-Institute (MRI) and TB-Leatherhead Food Research (LFR), respectively, and 0.91 compared with 0.73, 0.73 and 0.98 for breast muscle by LAM, HE, TB-MRI and TB-LFR, respectively). When applied to industrial samples, the results showed that it is possible by all methods to separate at least two different groups based on degree of degradation. In conclusion, the good image contrast, specificity of the staining and objectivity and transparency of the measurement speaks in favor of the LAM method as optimal to quantify degree of degradation of muscle structure in comminuted and fragmented chicken meat and obviously a likely candidate for a standard method.     

油管交流电磁加热技术在欢喜岭油田高结蜡井上的应用

欢26块杜家台油藏受地质条件、注入水质和配套工艺等因素影响,未能实施早期注水开发.由于长期依靠天然能量开发,区块处于低速开采阶段.为提高区块开发效果,实现注水开发,建立了一套以气动膜过滤为核心的水质精细处理系统,使注入水水质达到A1级标准;采用环氧树脂粉末涂层管线、井口过滤装置,防止了水质二次污染;改进高压注水管柱和实施注水井周期性防膨处理工艺,保证了注水井达到配注要求.通过采取上述措施,区块实现了稳产.研究结果对同类油藏高效注水开发具有借鉴意义.     

镇泾油田红河26-37井区微生物勘探研究

以镇泾油田微生物异常为基础,结合已有的区域地质资料、钻井和测井等资料,对镇泾油田红河26 - 37井区微生物异常区域进行了分析研究.根据微生物异常指标体系,论述了井区微生物异常分析结果,找出了井区内的微生物异常的分布规律,并对其勘探前景作出评价,对最有利目标区进行了含油气预测.     

石油微生物勘探技术在西柳地区的应用

将油气微生物勘探新技术应用于西柳地区进行采样,并进行了烃氧化菌培养,根据经验确定了本研究区的2个微生物异常区,即中北异常区和东南异常区。与研究区内现有已钻的12口井相比,其油气微生物勘探结果的符合率为75%,效果是良好的。同时,通过油气微生物勘探技术实践,总结并讨论了该技术分析结果的客观性以及地表和断层的影响因素、导致部分结果不相符的原因,这对我国复杂地下地质条件的油气勘探具有指导意义。最后,在油气微生物勘探结论的基础上,结合圈闭、油源等条件对试验区进行了含油性预测,并确定了最有利的布井点位.