Influences of preharvest spraying Cryptococcus laurentii combined with postharvest chitosan coating on postharvest diseases and quality of table grapes in storage

The effects of preharvest spray with Cryptococcus laurentii combined with chitosan coating after harvest on decay and quality of table grapes during storage periods were evaluated in the present study. Preharvest spray with C. laurentii (PreA) significantly decreased decay index (DI), and postharvest chitosan coating (PCC) enhanced the effectiveness of the pre-harvest spray when fruits were stored at 0 °C. PreA combination with PCC increased the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) of fruit in storage. PreA + PCC treatment was effective in reducing weight loss of fruits by 85% at 17 d storage and 38% at 42 d storage as compared to PreA alone at the same stage. In addition, PreA enhanced the ratio of soluble solids content (SSC) to titratable acid (TA) by 12% at harvest time, 7% at 17 d storage and 25% at 42 d storage, mainly by increasing SSC and decreasing TA in fruit stored at 0 °C. These results suggested that integration of preharvest spray with C. laurentii and postharvest chitosan coating treatment may be a promising management strategy for decay control and quality maintenance of table grapes.     

Application of biosensors in early detection of contamination with lactic acid bacteria during apple juice and concentrate production

The aim of Collective Research Project QUALI-JUICE (COLL-CT-2005, Co Nr 012461) was to introduce the biosensors in control of microbiologically pure apple juice production. Three commercial lactate biosensors were used and compared with enzyme kits assays. Parallel the microbiological analysis of the production process at one juice producing enterprise was done. The results of lactic acid assay with biosensors were in good correlation with those obtained by enzyme kits. The main benefit of biosensor use was shortening of measurement time as compared with assay by enzyme kit and possibility to measure at line. The concentration of l-lactic acid in apple pulp could be correlated with the number of lactic acid bacteria. Pasteurization process was eliminating lactic acid bacteria and the concentration of lactic acid was at this stage not exceeding 0.1 g L⁻¹. The final product (apple concentrate) contained in some cases very high amounts of lactic acid indicating secondary microbiological contamination after pasteurization step. Parallel microbiological analysis of production process and lactate assay indicated that the critical point during production was prolonged vacuum filtration after pasteurization.     

造纸厂锅炉补水质量的波动及共预防、检测和控制

制浆造纸厂锅炉系统在补水时,其补水中的污染物是威胁锅炉安全的一个重要因素,一旦受到冲击,脱盐系统受到的污染最为严重、要将污染物的危害降低到最低程度,首要对策就是要采取有效的预防措施、建立快速的检测系统和应用有效的控制程序？该论文对这三种方法进行了讨论     

油厂全电脑自动控制系统

介绍了浸出油厂采用主控电脑系统,实现全部工艺设备联动式自动化控制、全自动电机保护及故障报警监测,降低人为操作的干扰和损失,实现整个工艺流程产量和全自动平衡调节,各种生产报表自动生成系统,从而降低能源消耗,提高出油率和精炼率,增加安全系数,提高管理水平。     

PLC控制系统在原地清洗（CIP）中的应用

在利用工业控制计算机监控原地清洗设备的基础上,研制开发了新一代可编程控制器（PLC）和触摸屏构成的原地清洗控制系统。并介绍其控制原理及应用。     

线性矩阵不等式在冷却水温度控制系统中的应用

乳品生产过程自动化对产品质量提高具有重要意义。通常的PID控制器参数设计往往依据古典的方法或经验进行。为了利用满意控制设计控制器参数,讨论了线性矩阵不等式在冷却水温度控制系统的应用,并给出了实例。     

基于Internet网络的QoS控制技术探讨

为了解决网络传输延迟问题须在Internet中加入QoS控制技术。在其实现框架中,RSVP是最关键的一个协议。RSVP通过预约和保留传输路径中的资源来改善或保证用户应用QoS,而QoS控制技术与路由协议的结合利于改善Internet网络性能。     

纸料中树脂与沉积物的湿部化学特性

介绍了树脂及其沉积物的来源和种类、物理和化学特性、危害及其主要的湿部控制方法,为实际生产中解决树脂障碍提供了有效的理论基础。     

Rapid real-time PCR detection of Listeria monocytogenes in enriched food samples based on the ssrA gene, a novel diagnostic target

A real-time PCR assay was designed to detect a 162-bp fragment of the ssrA gene in Listeria monocytogenes. The specificity of the assay for L. monocytogenes was confirmed against a panel of 6 Listeria species and 26 other bacterial species. A detection limit of 1-10 genome equivalents was determined for the assay. Application of the assay in natural and artificially contaminated culture enriched foods, including soft cheese, meat, milk, vegetables and fish, enabled detection of 1-5 CFU L. monocytogenes per 25g/ml of food sample in 30h. The performance of the assay was compared with the Roche Diagnostics 'LightCycler foodproof Listeria monocytogenes Detection Kit'. Both methods detected L. monocytogenes in all artificially contaminated retail samples (n=27) and L. monocytogenes was not detected by either system in 27 natural retail food samples. The method developed in this study has the potential to enable the specific detection of L. monocytogenes in a variety of food types in a time-frame considerably faster than current standard methods. The potential of the ssrA gene as a nucleic acid diagnostic (NAD) target has been demonstrated in L. monocytogenes. We are currently developing NAD tests based on the ssrA gene for a range of common foodborne and clinically relevant bacterial pathogens.     

Factors associated with profitability in pasture-based systems of milk production

The global dairy industry needs to reappraise the systems of milk production that are operated at farm level with specific focus on enhancing technical efficiency and competitiveness of the sector. The objective of this study was to quantify the factors associated with costs of production, profitability, and pasture use, and the effects of pasture use on financial performance of dairy farms using an internationally recognized representative database over an 8-yr period (2008 to 2015) on pasture-based systems. To examine the associated effects of several farm system and management variables on specific performance measures, a series of multiple regression models were developed. Factors evaluated included pasture use [kg of dry matter/ha and stocking rate (livestock units/ha)], grazing season length, breeding season length, milk recording, herd size, dairy farm size (ha), farmer age, discussion group membership, proportion of purchased feed, protein %, fat %, kg of milk fat and protein per cow, kg of milk fat and protein per hectare, and capital investment in machinery, livestock, and buildings. Multiple regression analysis demonstrated costs of production per hectare differed by year, geographical location, soil type, level of pasture use, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, breeding season length, and capital investment in machinery, livestock, and buildings per cow. The results of the analysis revealed that farm net profit per hectare was associated with pasture use per hectare, year, location, soil type, grazing season length, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, and capital investment in machinery and buildings per cow. Pasture use per hectare was associated with year, location, soil type, stocking rate, dairy farm size, fat %, protein %, kg of fat and protein per cow, farmer age, capital investment in machinery and buildings per cow, breeding season length, and discussion group membership. On average, over the 8-yr period, each additional tonne of pasture dry matter used increased gross profit by €278 and net profit by €173 on dairy farms. Conversely, a 10% increase in the proportion of purchased feed in the diet resulted in a reduction in net profit per hectare by €97 and net profit by €207 per tonne of fat and protein. Results from this study, albeit in a quota limited environment, have demonstrated that the profitability of pasture-based dairy systems is significantly associated with the proportion of pasture used at the farm level, being cognizant of the levels of purchased feed.