脉冲强光杀菌装置的初步设计研究

脉冲强光杀菌是一种新兴的冷杀菌技术,本文设计脉冲强光杀菌的发生电路,对其进行了初步的设计研究,使用双电源脉冲发生电路提供能量。     

自动控制脉冲强光杀菌装置的研制

采用单片机控制技术，研制了自动控制脉冲强度杀菌装置。每个光脉冲的输入能量可达６００～２２００Ｊ；光脉冲宽度经测定小于８００μＳ。３０个光脉冲能使大肠杆菌减少５个数量级，４０个光脉冲以使蛋白酶的活力钝化９０％，脉冲强光杀菌可事负透明塑料薄膜包装的切片面包的保存期延长１倍以上，脉冲强光杀菌是一种很有发展前途的冷杀菌技术。     

脉冲强光杀菌技术的研究

采用脉冲强光杀菌输入能量为７００Ｊ，光脉冲宽度小于８００μｓ，当闪照次数多于３０次时间使枯草芽孢力，酵母为１０＾５个／ｍｌ减少到０个，在一定时间内，分段照射剂杀菌效果影响不大，杀菌作用的主要波段可能是紫外线，脉冲强光不改变菌液的电导率，使其电位有较大的改变。     

脉冲强光杀菌在水处理中的应用

介绍了饮用水生产中的杀菌方法及存在的主要问题,介绍了脉冲强光杀菌原理,并展望了该方法在水处理的广阔应用前景。     

脉冲强光杀菌技术对氨基酸饮料杀菌作用的研究

文章研究脉冲强光对氨基酸饮料中微生物杀灭效果,通过单因素实验方法优化脉冲强光对氨基酸饮料杀菌工艺。结果表明最佳杀菌参数为:闪照距离8cm,闪照时间25s,染菌浓度为104CFU.mL^-1。对脉冲强光杀菌处理和模拟常规热杀菌处理进行对比试验,分析2种杀菌处理技术对氨基酸饮料主要营养成分的变化情况,结果表明脉冲强光杀菌技术可以较好的保护饮料中的营养成分,为脉冲强光杀菌技术应用于饮料杀菌奠定理论基础。     

脉冲强光对两种霉菌和两种酵母菌的杀菌效果研究

采用自行研制的脉冲强光杀菌装置处理黑霉菌、灰霉菌两种霉菌和热带假丝酵母、啤酒酵母两种酵母菌,研究脉冲强光光流量与这四种微生物杀菌效果之间的关系。结果表明,脉冲强光对这四种微生物的杀菌效果显著。随着光流量增大,霉菌和酵母菌的致死率增大,霉菌的菌落直径和产孢量减小。在闪照次数为16次,菌液厚度3.4mm,菌液透光率100%,光流量达到37.302mJ/cm~2时,两种霉菌的致死率均达到99.04%以上,霉菌菌落直径与对照组相比均减少了77.33%以上,产孢量均占对照组的4.00%以下。两种酵母菌的致死率均达到100%。      

脉冲强光对大肠杆菌的杀菌实验研究

脉冲强光杀菌是一种新兴的冷杀菌技术,自制脉冲强光杀菌装置,光脉冲的脉冲宽度为20μs,最大输入能量为644J。使用该装置对大肠杆菌进行杀菌实验,对脉冲强光的杀菌影响因素进行研究。结果表明,脉冲强光对大肠杆菌的杀菌效果十分显著,输入电压2500V时,闪照4次能达到完全致死。各因素对脉冲强光杀菌效果影响的主次顺序是:闪照次数>输入电压>菌液透光率>菌液厚度。此外,杀菌菌液的物理性质对杀菌效果有较大影响。      

脉冲强光对煎饼中细菌的杀菌效果的研究

煎饼在包装和贮藏过程中易受微生物的二次污染,严重影响其食用安全性,采用脉冲强光杀菌技术可有效杀死煎饼中的微生物。结果表明:脉冲能量为400J、次数20次、距离10.9cm、频次2次/s,在此优化条件下脉冲强光对煎饼中细菌杀菌率达到99.4%。      

脉冲强光对煎饼中细菌的杀菌效果的研究

煎饼在包装和贮藏过程中易受微生物的二次污染,严重影响其食用安全性,采用脉冲强光杀菌技术可有效杀死煎饼中的微生物。结果表明:脉冲能量为400J、次数20次、距离10.9cm、频次2次/s,在此优化条件下脉冲强光对煎饼中细菌杀菌率达到99.4%。     

脉冲强光对两种老霉菌和两种酵母菌的杀菌效果研究

采用自行研制的脉冲强光杀菌装置处理黑霉菌、灰霉菌两种霉菌和热带假丝酵母、啤酒酵母两种酵母菌,研究脉冲强光光流量与这四种微生物杀菌效果之间的关系.结果表明,脉冲强光对这四种微生物的杀菌效果显著.随着光流量增大,霉菌和酵母菌的致死率增大,霉菌的菌落直径和产孢量减小.在闪照次数为16次,菌液厚度3.4mm,菌液透光率100%,光流量达到37.302mJ/cm2时,两种霉菌的致死率均达到99.04%以上,霉菌菌落直径与对照组相比均减少了77.33%以上,产孢量均占对照组的4.00%以下.两种酵母菌的致死率均达到100%.     

小型高压脉冲电场杀菌系统的试制

阐述了高压脉冲电场杀菌系统的一般组成，并介绍了高压脉冲电源的原理及食品处理室的结构，探讨了电场强度和杀菌效果的关系。试验结果表明：在试验参数的条件下，牛奶中大肠杆菌死亡率达99％。     

Advanced retorting,microwave assisted thermal sterilization (MATS), and pressure assisted thermal sterilization (PATS) to process meat products

Conventional thermal processes have been very reliable in offering safe sterilized meat products, but some of those products are of questionable overall quality. Flavor, aroma, and texture, among other attributes, are significantly affected during such processes. To improve those quality attributes, alternative approaches to sterilizing meat and meat products have been explored in the last few years. Most of the new strategies for sterilizing meat products rely on using thermal approaches, but in a more efficient way than in conventional methods. Some of these emerging technologies have proven to be reliable and have been formally approved by regulatory agencies such as the FDA. Additional work needs to be done in order for these technologies to be fully adopted by the food industry and to optimize their use. Some of these emerging technologies for sterilizing meat include pressure assisted thermal sterilization (PATS), microwaves, and advanced retorting. This review deals with fundamental and applied aspects of these new and very promising approaches to sterilization of meat products.     

Ohmic sterilization inside a multi-layered laminate pouch for long-duration space missions

A pouch that can be used to ohmically reheat and sterilize food and later reused to stabilize waste will significantly reduce the Equivalent System Mass during a long term space mission. Reheating of food and stabilization of waste have been successfully done in the past using a V-shaped electrode pouch using pulsed ohmic heating, however improvement of field distribution was needed. The main goals of this work were to develop an improved pouch design to facilitate uniform ohmic heating of food; to model ohmic sterilization within the pouch; and to verify the model through an inoculated pack study.     

Optimization of processing conditions for the sterilization of retorted short-rib patties using the response surface methodology

The aim of this study was to determine the optimum sterilization conditions for short-rib patties in retort trays by considering microbiological safety, nutritive value, sensory characteristics, and textural properties. In total, 27 sterilization conditions with various temperatures, times, and processing methods were tested using a 3³ factorial design. The response surface methodology (RSM) and contour analysis were applied to find the optimum sterilization conditions for the patties. Quality attributes were significantly affected by the sterilization temperature, time, and processing method. From RSM and contour analysis, the final optimum sterilization condition of the patties that simultaneously satisfied all specifications was determined to be 119.4 °C for 18.55 min using a water-cascading rotary mode. The findings of the present study suggest that using optimized sterilization conditions will improve the microbial safety, sensory attributes, and nutritional retention for retorted short-rib patties.     

Development and evaluation of alternative processes for sterilization and deodorization of cork barks and natural cork stoppers

Cork taint, one of the most known off-flavours in wine, is usually attributed to the presence of the aromatic compound 2,4,6-trichloroanisole (2,4,6-TCA) in cork stoppers made from the bark of the cork oak, Quercus suber. There are many major chemical/biochemical pathways through which 2,4,6-TCA can be formed during cork production. The estimated incidence of cork-tainted wine bottles ranges from 2–to 7%, costing global wine industry approximately US$ 10 billion annually. During this study, a laboratory-scale system was designed and constructed, to efficiently treat cork bark and stopper samples using ozone and/or other sterilizing gases, such as steam, via sequential application of pulsed vacuum–pressure cycles. The developed physicochemical processes were studied and evaluated in order to achieve both sterilization conditions and 2,4,6-TCA removal without affecting the mechanical and bottling properties of cork. According to the results, the application of ozone alone seems to be a promising treatment method for cork barks. However, the pulsed treatment ensures both sufficient removal (99%) of both bacteria and moulds from cork stoppers when combined with ozone or steam and satisfactory deodorization of cork stoppers achieving high percentages (90%) of 2,4,6-TCA removal when combined with steam. The operating cost of each alternative process (plain or pulsed, with or without ozone and/or steam) was estimated and compared, in laboratory scale, for the selection of the most efficient process, taking into account technicoeconomical aspects.     

高频电热杀菌腔内粉料食品测温传感器的电磁屏蔽研究

设计了高频电加热粉料杀菌设备,将杀菌腔内粉料的螺旋推进器作为加热部件而接通高频电。高频电加热会在周围产生较强的磁场,干扰铂电阻对关键控制点的准确测温,需进行电磁屏蔽处理。从理论分析和虚拟仿真两方面入手,理论分析得到材料的相对磁导率、电导率及厚度影响材料的屏蔽效能,虚拟仿真得到几种材料以及材料不同厚度的屏蔽效能。找到了合适铂电阻的屏蔽材料为锰锌铁氧体,并确定圆柱形屏蔽罩厚度为3mm,屏蔽效能可达40dB以上,经实验验证该种屏蔽罩的屏蔽效果符合屏蔽要求。     

Investigation of desirable hydrostatic pressure required to sterilize Bacillus stearothermophilus IFO 12550 spores and its sterilization properties in glucose, sodium chloride and ethanol solutions

Desirable hydrostatic pressure required to sterilize Bacillus stearothermophilus IFO 12550 spores and its sterilization properties in glucose, sodium chloride and ethanol solutions were investigated. Spores were inactivated as treatment temperature (35 to 95°C) increased at 50 and 100 MPa. The Pz (pressure z) values were 29.32 MPa under the pressure ranged from 10 to 60 MPa and 545.6 MPa in under 60 to 100 MPa at 95°C. Therefore, 60 MPa was the desirable pressure to sterilize the spores at 95°C. Glucose, sodium chloride and ethanol respectively decrease the inactivation rate of the spores significantly (P<0.05) except for 6% glucose. The spores were inactivated at 60 MPa, 95°C for 420 to 540 min in the media with various food additives. The PD (pressure D) values ranged from 75.2 min (containing no food additives) to 86.2 min (containing 20% ethanol).     

果汁冷杀菌技术

对超高压杀菌、脉冲电场杀菌、辐照杀菌、高密度CO2技术等4种果汁冷杀菌技术进行了简要的介绍。它们的共同特征就是可以减少由于加热而造成的果汁的营养成分和风味的丧失,并分别对杀菌机理、各自的优缺点及应用前景进行了分析。     

高压脉冲电场与热灭菌技术相结合对大肠杆菌的杀菌效果

高压脉冲电场灭菌技术是近年来发展起来的极有潜力的非热灭菌技术,但由于其参数较多,对于最佳的灭菌参数至今未有定论。所以该论文提出了一种将高压脉冲电场灭菌与传统的热杀菌技术相结合的灭菌技术,旨在发挥两者的优点,实现一种简单、节能、快速、安全、高效的灭菌技术。通过实验,可以发现,将大肠杆菌在45℃条件下进行预热5min后再进行高压脉冲电场灭菌,大肠杆菌的存活率已降至13.69%。这样既节省了能源,又适用于一些不能够加热至45℃以上的食物灭菌,是一种可以广泛应用的灭菌技术。