不同介质中甲型副伤寒沙门氏菌的热失活特性

研究甲型副伤寒沙门氏菌在不同介质中热失活规律,对接种10~8 CFU/g甲型副伤寒沙门氏菌的不同介质进行55、63、72℃热处理,测定处理后样品中甲型副伤寒沙门氏菌的菌体浓度。应用Dose Resp模型拟合在3种温度下志贺氏菌的动力学模型,用D值(decimal reduction time)表示甲型副伤寒沙门氏菌在不同介质中的耐热情况。结果表明:甲型副伤寒沙门氏菌的热失活曲线运用Dose Resp模型拟合较好,相关系数均在0.97以上。甲型副伤寒沙门氏菌在不同介质中的D值不同,在蛋白质和脂肪含量较高的灌肠肥瘦肉1∶1(m/m)中D值较大,相对耐热。55℃条件下热处理25.0 min,63℃热处理2.03 min,72℃热处理0.31 min后,一般肉制品中甲型副伤寒沙门氏菌均能被杀死。     

牛肉中沙门氏菌热失活模型的建立

为了建立牛肉中沙门氏菌的热失活动力学模型,将4种不同血清型的沙门氏菌混合菌液接种到牛肉表面,将接种后的牛肉分别在55、57.5、60、62.5和65 ℃下进行加热处理。不同温度下的沙门氏菌热失活曲线用Weibull模型进行了拟合,判定系数(R²)分别为0.993(55 ℃)、0.984(57.5 ℃)、0.999(60 ℃)、0.999(62.5 ℃)和0.998(65 ℃)。进一步建立了温度对Weibull一级失活模型参数(b)影响的二级模型,即ln(b)=0.47T-28.07。用58.5和64 ℃下实际的沙门氏菌存活数对所建的模型进行验证,准确度(A_f)和偏差度(B_f)分别为1.071和1.056,0.998和1.002,均在可接受范围内。本研究所建立的模型能较好的模拟不同温度(55~65 ℃)对牛肉中沙门氏菌热失活的影响。     

市售小酥肉中沙门菌热失活模型的建立与验证

目的 研究不同加热温度下小酥肉中沙门菌的热失活规律,以期为安全消费提供指导。方法 将接种10⁸ CFU/g鼠伤寒沙门菌的小酥肉在80℃、90℃、100℃、110℃和120℃,热处理一定时间后活菌计数,使用线性模型、Logistic模型和Weibull模型对小酥肉中沙门菌的热失活规律进行研究,并通过外部实验对模型进行验证。结果 与线性模型和Logistic模型相比,Weibull模型更适用于描述小酥肉中沙门菌热失活状况,其一级模型判定系数R²均在0.992 1以上,二级模型R²分别为0.949 2、0.995 9,用95℃和105℃温度对模型进行验证时的准确度Af、偏差度Bf均在可接受范围内,说明实验构建的模型可较好地描述80℃～120℃温度范围内小酥肉中沙门菌的失活规律。结论 本研究有望为小酥肉安全加热时间提供参考,同时为小酥肉微生物相关风险评估提供模型支持。     

大豆抗营养因子钝化失活速度的研究

对不同热处理条件下,大豆不同抗营养因子的钝化失活速度进行研究。结果表明,在脲酶完全失活条件下,胰蛋白酶抑制素仍残留一定活性。因此在大豆加工中以脲酶做为抗营养因子失活指标不能全面反映大豆及其制品中抗营养因子的失活状况。     

肉桂醛促进即食牛肉中蜡样芽孢杆菌热失活的动力学模型

为了研究不同浓度肉桂醛对即食牛肉中蜡样芽孢杆菌热失活动力学的影响规律,建立热失活一级模型和二级模型,设定肉桂醛质量分数梯度为0%、0.1%、0.5%、1%,温度为55、60、65、70℃,预测即食牛肉中蜡样芽孢杆菌的失活曲线。结果表明,Weibull模型可准确描述蜡样芽孢杆菌的热失活规律,随着肉桂醛浓度的增加,对牛肉中蜡样芽孢杆菌的抑制效果显著增加,在55、60、65、70℃时,添加1%肉桂醛使即食牛肉中蜡样芽孢杆菌的t_5.0分别降低了17、8.98、2.82和1.4 min,使用多项式模型进行二级模型的拟合,拟合效果较好。因此,该研究得出,肉桂醛可显著降低蜡样芽孢杆菌的热抵抗性,减少热杀菌对即食食品品质的影响,所建立的蜡样芽孢杆菌热失活预测模型,可为即食牛肉制品安全控制技术的建立提供参考。     

大豆抗营养因子钝化失活速度的研究

对不同热处理条件下,大豆抗营养因子的钝化失活速度进行了研究.结果表明,在脲酶（UA）完全失活条件下,胰蛋白酶抑制素（TI）仍残留一定活性.因此在大豆加工中,以脲酶做为抗营养因子失活指标不能全面反映大豆及其制品中抗营养因子的失活状况.     

热协同超高压对不同介质中嗜热脂肪芽孢杆菌芽孢的灭活作用

以磷酸缓冲液及经过人工接种的牛乳、鸡腿菇和卤牛肉为对象,考察超高压协同热处理对嗜热脂肪芽孢杆菌灭活的影响,测定处理前后的细菌菌落总数。结果表明,嗜热脂肪芽孢杆菌的失活率依次为:牛乳>磷酸缓冲液>鸡腿菇>卤牛肉。处理组500/60℃、500/90℃、600/80℃,5min、10min,牛乳中失活率(-2.18,-2.82,-3.32)高于磷酸缓冲液中的失活率(-1.62,-2.78,-2.98);卤牛肉中的失活率低于鸡腿菇中的失活率。说明在热协同超高压杀灭嗜热脂肪芽孢杆菌过程中,牛乳中存在利于诱导芽孢发芽的物质,使芽孢失去原有的对热的抵抗力,而在鸡腿菇和卤牛肉中失活率较牛乳低是由于其水分活度较低,卤牛肉中的失活率低于鸡腿菇中的失活率是由于NaCl对芽孢有保护作用,增加了其对压力的耐受性。     

生孢梭菌孢子生长与失活模型的统一化研究

为探讨预测微生物生长和失活的预测模型统一化问题,研究将生孢梭菌孢子热失活“镜像化”曲线用描述微生物生长的Gompertz 模型和Baranyi 模型进行模拟,并通过标准预测误对两种模型进行比较。实验表明：两种模型都能较好的模拟生孢梭菌孢子热失活,但t 检验分析差异不显著,标准预测误比较表明Gompertz 模型优于Baranyi 模型。建议用Gompertz 模型统一描述生孢梭菌孢子生长和失活情况。     

小肠结肠炎耶尔森菌在猪肉中失活/存活模型的初步研究

采用预测微生物学的基本方法和程序,研究小肠结肠炎耶尔森菌在特定条件下的生长规律,并用CurveExpert1.38软件作为辅助工具,从中选取了Linear模型对实验数据进行拟合。初步建立了肉汤中小肠结肠炎耶尔森菌55、60℃的热失活模型,以及猪肉中小肠结肠炎耶尔森菌的速冻失活模型和冷冻存活模型。      

荠菜过氧化物酶热失活动力学的研究

目的 研究热烫处理引起荠菜过氧化酶(POD)失活的速率常数和动力学规律。方法 对荠菜在80～100℃的热水处理一定时间条件,对荠菜过氧化酶的残余活性进行测定,并用一级动力学模型对过氧化物酶失活动力学进行拟合,分析失活速率常数。结果 热烫处理钝化新鲜荠菜POD活性效果明显,在80～100℃处理范围内,随着处理温度的上升,荠菜POD 失活速率常数k 值从0.01702增加到0.14260,反应活化能为114 kJ/mol。一级动力学模型拟合决定系数R²＞0.99。结论 荠菜POD 的热失活动力学符合一级动力学模型。     

Trends in microbial control techniques for poultry products

Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.     

Evaluation of the safety assurance level for Salmonella spp. throughout the food production chain in Switzerland

In Switzerland. the safeguarding of food is the responsibility of industry, organizations, and governmental authorities. The dispersion of the tasks and the diversity of implemented safety measures among involved stakeholders do not allow a general overview of the national safety assurance level provided. A comprehensive evaluation of the level of safety assurance provided for foodborne pathogens such as Salmonella spp. is therefore lacking, and the prevalence of Salmonella spp. at various points in the food production chain is not known. The objectives of this study were to (i) collect data on safety measures implemented throughout the food production chain in Switzerland regarding Salmonella spp.; (ii) evaluate the safety assurance level for Salmonella spp. at each step of the production chain for chicken meat, pork, beef, and milk and dairy products (bovine origin); and (iii) gather data on the prevalence of the pathogen at each step. Data on implemented safety assurance measures for Salmonella spp. were gathered from the various stakeholders in the food production chain. The data were analyzed by a semiquantitative method that considered the quality and relevance of the implemented safety measures for Salmonella spp. The safety assurance level for Salmonella spp. was evaluated from "no safety assurance" to "very good safety assurance." Available results of testing for Salmonella spp. from 1998 to 2000 were used for calculating the prevalence of the pathogen throughout the food production chain. The results showed a varying safety assurance level for Salmonella spp. throughout the food production chain. Strengths (e.g., feed production for chickens) and weaknesses (e.g., pork production) were observed. These results serve as a basis for a rational optimization of the system.     

Prospective Applications of Cold Plasma for Processing Poultry Products: Benefits,Effects on Quality Attributes,and Limitations

Eliminating the pathogens from the chicken egg and meat is of supreme value for food scientists. In this regard, researchers have explored the potential applications of cold plasma, as a promising technique, to increase the profitability of poultry farming and safety of the poultry products. In the present study, an overview of the conducted research on plasma treatment of poultry products is presented to highlight the potential benefits of this emerging technology for the food and poultry industries. The potential negative effects of plasma treatment on the quality attributes of the product are also discussed. Moreover, the limitations of this technology and considerations for its commercial applications are illustrated. Furthermore, the needs for future research in this area of science are pointed out. Several studies have confirmed the applicability of cold plasma for egg and chicken decontamination. Considering the number of the recently conducted research and on‐going advances in plasma science, this technique may assist food producers in enhancing the poultry product safety in the near future.     

我国鸡肉产品中沙门氏菌风险评估的研究进展

本文综述了国内外鸡肉相关产品中沙门氏菌的风险评估研究现状,包括沙门氏菌预测微生物学、评估模型、剂量反应模型及风险评估软件的使用,指出了目前我国鸡肉产品中沙门氏菌风险评估研究中存在的问题,并提出下一步鸡肉中沙门氏菌风险评估工作的研究方向及重点,为政府食品安全监管和理性决策提供科学的理论参考,同时也为消费者日常饮食选择提供风险预警的理论借鉴。     

Advanced applications of chemo-responsive dyes based odor imaging technology for fast sensing food quality and safety: A review

Public attention to foodquality and safety has been increased significantly. Therefore, appropriate analytical tools are needed to analyze and sense the food quality and safety. Volatile organic compounds (VOCs) are important indicators for the quality and safety of food products. Odor imaging technology based on chemo-responsive dyes is one of the most promising methods for analysis of food products. This article reviews the sensing and imaging fundamentals of odor imaging technology based on chemo-responsive dyes. The aim is to give detailed outlines about the theory and principles of using odor imaging technology for VOCs detection, and to focus primarily on its applications in the field of quality and safety evaluation of food products, as well as its future applicability in modern food industries and research. The literatures presented in this review clearly demonstrated that imaging technology based on chemo-responsive dyes has the exciting effect to inspect such as quality assessment of cereal , wine and vinegar flavored foods , poultry meat, aquatic products, fruits and vegetables, and tea. It has the potential for the rapid, reliable, and inline assessment of food safety and quality by providing odor-image-basedmonitoring tool. Practical Application : The literatures presented in this review clearly demonstrated that imaging technology based on chemo-responsive dyes has the exciting effect to inspect such as quality assessment of cereal , wine and vinegar flavored foods, poultry meat, aquatic products, fruits and vegetables, and tea.     

Modeling the inactivation of Salmonella Typhimurium, Listeria monocytogenes, and Salmonella Enteritidis on poultry products exposed to pulsed UV light

Pulsed UV light inactivation of Salmonella Typhimurium on unpackaged and vacuum-packaged chicken breast, Listeria monocytogenes on unpackaged and vacuum-packaged chicken frankfurters, and Salmonella Enteritidis on shell eggs was explained by log-linear and Weibull models using inactivation data from previous studies. This study demonstrated that the survival curves of Salmonella Typhimurium and L. monocytogenes were nonlinear exhibiting concavity. The Weibull model was more successful than the log-linear model in estimating the inactivations for all poultry products evaluated, except for Salmonella Enteritidis on shell eggs, for which the survival curve was sigmoidal rather than concave, and the use of the Weibull model resulted in slightly better fit than the log-linear model. The analyses for the goodness of fit and performance of the Weibull model produced root mean square errors of 0.059 to 0.824, percent root mean square errors of 3.105 to 21.182, determination coefficients of 0.747 to 0.989, slopes of 0.842 to 1.042, bias factor values of 0.505 to 1.309, and accuracy factor values of 1.263 to 6.874. Overall, this study suggests that the survival curves of pathogens on poultry products exposed to pulsed UV light are nonlinear and that the Weibull model may generally be a useful tool to describe the inactivation patterns for pathogenic microorganisms affiliated with poultry products.     

Modelling Salmonella concentration throughout the pork supply chain by considering growth and survival in fluctuating conditions of temperature, pH and a(w)

We aim to predict the population density of Salmonella spp. through the pork supply chain under dynamic environmental conditions (pH, a(w) and temperature) that fluctuate from growth to survival/slow inactivation. To do this, the dependence of the probability of growth, and of the growth and inactivation rate on the temperature, pH and a(w) were modelled. Probabilistic and kinetic measurements, i.e. growth and survival curves, were collected from the ComBase database (www.combase.cc). Conditions at which selected data used to fit the models were generated covered wide ranges that are relevant to the pork supply chain. Probabilistic and kinetic models were combined to give predictions on the concentration of Salmonella spp. at any stage of the pork supply chain under fluctuating pH, a(w) and/or temperature. Models were implemented in a user-friendly computing tool freely available from http://www.ifr.ac.uk/safety/SalmonellaPredictions/. This program provides estimates on the population dynamics of Salmonella spp. at any stage of the pork supply chain and its predictive performance has been validated in several pork products.     

畜禽副产物蛋白质及其水解物的美拉德反应在食品加工中的应用

畜禽副产物产量大,蛋白质等营养物质含量高,但利用率低,应用范围有限,造成资源的浪费。我国畜禽加工副产物附加值较低,如果能够提高畜禽副产物的利用率,不但可充分利用现有资源,还可减少环境污染。本文以阐述畜禽副产物蛋白质的研究情况为主,围绕副产物蛋白质的水解、产物的生物活性以及其进行美拉德反应后产物在食品加工工业的应用概况进行综述,为提高畜禽副产物蛋白的利用率,拓宽其应用范围,加强畜禽副产物蛋白质及水解物的深加工利用、新产品开发提供理论依据。     

沙门氏菌生物菌膜形成的分子调控研究进展

沙门氏菌是全球范围内危害公众健康的主要食源性致病菌，每年造成千万人食物中毒。黏附于食品加工接触面的生物菌膜是沙门氏菌交叉污染的源头，其对消毒剂具有极强的耐受抵抗作用，可引发大规模食物中毒并导致食品召回。本文在论述细菌黏附辅助体（菌毛和鞭毛）和胞外多聚物对生物菌膜的具体作用及其在mRNA转录层面调控效应的基础上，重点阐述了转录后层面上的非编码小RNA（non-coding small RNA，sRNA）及其对移动性、胞外多聚物等核心mRNA通路的调控机制，并归纳出sRNA调控生物菌膜的4 种作用模式，最后对该领域的研究前景进行了前瞻性展望，以期为拓展研究思路、完善生物菌膜的科学理论和研发针对性控制技术提供参考。     

小麦中呕吐毒素研究进展

小麦是全球三大谷物之一。由镰刀菌引起的小麦赤霉病是我国最主要的小麦病害之一,能造成小麦严重减产、品质下降,而且镰刀菌还能产生多种真菌毒素,进一步危害小麦及其制品的质量安全,其中,呕吐毒素(deoxynivalenol, DON)是小麦中检出率最高、危害最严重的真菌毒素之一,已成为关系小麦及其制品食用安全的重要问题。DON在小麦等谷物及其制品中的污染和防控是全球面临的严峻挑战,对DON进行定期检测和污染分析,研究高效、安全的降解技术,确保消费者安全,已成为目前世界各国政府和公众广泛关注和高度重视的热点问题。本文综述了DON的理化性质及毒性、影响产生的因素、污染现状及防控与脱毒方面的研究进展情况,以期为小麦中DON的风险评估及防控策略的制定提供有利参考。