基于微生物和量纲模型对茶叶货架期的研究

茶叶在贮藏和销售过程中易受到理化及微生物的影响,造成茶叶保质期短,严重阻碍茶业发展。为更好地探索茶叶微生物生长模型对茶叶货架期的影响,该文对微生物生长学一级、二级模型的含义与内容进行概述,并剖析茶叶品质的影响因素,主要从微生物和物理角度来对茶叶货架期的评价,归纳和建立茶叶货架期的预测模型。以提高茶叶卫生检测效率,保证茶叶质量安全,延长茶叶保质期。     

Predictive modelling of the growth and survival of Listeria in fishery products

Predictive microbiology provides a powerful tool to aid the exposure assessment phase of 'quantitative microbial risk assessment'. Using predictive models changes in microbial populations on foods between the point of production/harvest and the point of eating can be estimated from changes in product parameters (temperature, storage atmosphere, pH, salt/water activity, etc.). Thus, it is possible to infer exposure to Listeria monocytogenes at the time of consumption from the initial microbiological condition of the food and its history from production to consumption. Predictive microbiology models have immediate practical application to improve microbial food safety and quality, and are leading to development of a quantitative understanding of the microbial ecology of foods. While models are very useful decision-support tools it must be remembered that models are, at best, only a simplified representation of reality. As such, application of model predictions should be tempered by previous experience, and used with cognisance of other microbial ecology principles that may not be included in the model. Nonetheless, it is concluded that predictive models, successfully validated in agreement with defined performance criteria, will be an essential element of exposure assessment within formal quantitative risk assessment. Sources of data and models relevant to assessment of the human health risk of L. monocytogenes in seafoods are identified. Limitations of the current generation of predictive microbiology models are also discussed. These limitations, and their consequences, must be recognised and overtly considered so that the risk assessment process remains transparent. Furthermore, there is a need to characterise and incorporate into models the extent of variability in microbial responses. The integration of models for microbial growth, growth limits or inactivation into models that can predict both increases and decreases in microbial populations over time will also improve the utility of predictive models for exposure assessment. All of these issues are the subject of ongoing research.     

冰鲜鸡肉品质及其货架期的研究进展与展望

相对于热鲜鸡肉和冷冻鸡肉,冰鲜鸡肉在口感、风味、新鲜度以及营养等方面具有很大优势,具有很好的市场发展前景。但冰鲜鸡肉的品质在生产加工和流通过程中容易发生腐败变质。随着消费者食品安全意识的日益提高,冰鲜鸡肉的品质及其货架期受到越来越多的关注。本文总结了冰鲜鸡肉的品质表征指标;阐述了微生物因素、物理因素以及化学因素对冰鲜鸡肉品质的影响;比较了化学、超高压和辐照等6种保鲜技术对冰鲜鸡肉保鲜的效果及特点;结合食品货架期预测模型,梳理了已有预测冰鲜鸡肉货架期的相关研究;最后分析了冰鲜鸡肉品质及其货架期的研究现状,并对其未来的研究趋势进行了展望,指出随着研究技术、手段和保鲜技术的不断发展,冰鲜鸡肉货架期的研究也将不断向实用和智能化的方向发展。     

分子生物学技术在预测微生物学中的应用与展望

预测微生物学是食品微生物学的重要组成部分,其本质在于利用数学模型描述特定环境条件下微生物的生长和死亡规律。预测微生物模型既能应用于预测食品的货架期、控制腐败菌的滋生,又有助于完善食品微生物风险评估体系,减少致病菌的患病风险,对保障食品安全和改善公共卫生状况具有十分重要的意义。本文以综述的形式,概述预测微生物学的发展历史,并分析当前预测微生物学的研究热点。在此基础之上,着重介绍分子生物学技术在预测微生物学中应用的最新研究进展,阐述分子预测模型的概念和构建方法,并对其他分子生物学技术在预测微生物学中应用的可行性以及分子预测模型的应用前景进行展望,以期为全面推动预测微生物学这一学科的进步提供理论参考。     

Bacteriocins: Recent Trends and Potential Applications

In the modern era, there is great need for food preservation in both developing and developed countries due to increasing demand for extending shelf life and prevention of spoilage of food material. With the emergence of new pathogens and ability of micro-organisms to undergo changes, exploration of new avenues for the food preservation has gained importance. Moreover, awareness among consumers regarding harmful effects of chemical preservatives has been increased. Globally, altogether there is increasing demand by consumers for chemical-free and minimal processed food products. Potential of bacteriocin and its application in reducing the microbiological spoilages and in the preservation of food is long been recognized. Bacteriocins are normally specific to closely related species without disrupting the growth of other microbial populations. A number of applications of bacteriocin have been reported for humans, live stock, aquaculture etc. This review is focused on recent trends and applications of bacteriocins in different areas in addition to their biopreservative potential.     

Predictive microbiology: Quantitative science delivering quantifiable benefits to the meat industry and other food industries

Predictive microbiology is considered in the context of the conference theme "chance, innovation and challenge", together with the impact of quantitative approaches on food microbiology, generally. The contents of four prominent texts on predictive microbiology are analysed and the major contributions of two meat microbiologists, Drs. T.A. Roberts and C.O. Gill, to the early development of predictive microbiology are highlighted. These provide a segue into R&D trends in predictive microbiology, including the Refrigeration Index, an example of science-based, outcome-focussed food safety regulation. Rapid advances in technologies and systems for application of predictive models are indicated and measures to judge the impact of predictive microbiology are suggested in terms of research outputs and outcomes. The penultimate section considers the future of predictive microbiology and advances that will become possible when data on population responses are combined with data derived from physiological and molecular studies in a systems biology approach. Whilst the emphasis is on science and technology for food safety management, it is suggested that decreases in foodborne illness will also arise from minimising human error by changing the food safety culture.     

Modified Atmosphere Packaging Technology of Fresh and Fresh-cut Produce and the Microbial Consequences—A Review

Modified atmosphere packaging (MAP) technology offers the possibility to retard the respiration rate and extend the shelf life of fresh produce, and is increasingly used globally as value adding in the fresh and fresh-cut food industry. However, the outbreaks of foodborne diseases and emergence of resistant foodborne pathogens in MAP have heightened public interest on the effects of MAP technology on the survival and growth of pathogenic organisms. This paper critically reviews the effects of MAP on the microbiological safety of fresh or fresh-cut produce, including the role of innovative tools such as the use of pressurised inert/noble gases, predictive microbiology and intelligent packaging in the advancement of MAP safety. The integration of Hazard Analysis and Critical Control Points-based programs to ensure fresh food quality and microbial safety in packaging technology is highlighted.     

预测微生物学在禽肉质量安全控制中的应用

预测微生物学是运用数学、工程学、统计学和微生物学建立数学模型,对食品中微生物的生长和残存进行定量分析。本文对国内外的预测软件进行简介,并介绍了预测微生物学在禽肉中的研究进展及质量安全控制中的应用。     

基于食品安全性的预测微生物学研究模式

预测微生物学是依据各种食品微生物在不同加工、贮藏和流通条件下的基础信息库,预测食品中微生物数量的动态变化,并对食品的安全性做出快速判断的一门学科研究新领域。预测微生物学的核心在于建立完善的数学模型。介绍了预测微生物学的研究模式以及其与不同学科的结合方式,并聚焦到将成为预测微生物学未来发展源动力的神经元网络技术。     

预测微生物学及其在食品科学中的应用

预测微生物学是运用微生物学、工程数学以及统计学进行数学建模,利用所建模型,通过计算机及其配套软件,预测和描述处在特定的环境下微生物的生长和死亡规律。预测微生物学模型按Whiting和Buchanan的分类方法分为初级模型、次级模型和三级模型,文中按该分类方法分别对预测微生物学及其模型的发展进行了系统的介绍,并对预测微生物学在食品科学中的应用进行了综述,为在食品工业中更好的利用预测微生物学提供帮助。     

Application of predictive modelling techniques in industry: from food design up to risk assessment

In this communication, examples of applications of predictive microbiology in industrial contexts (i.e. Nestlé and Unilever) are presented which cover a range of applications in food safety from formulation and process design to consumer safety risk assessment. A tailor-made, private expert system, developed to support safe product/process design assessment is introduced as an example of how predictive models can be deployed for use by non-experts. Its use in conjunction with other tools and software available in the public domain is discussed. Specific applications of predictive microbiology techniques are presented relating to investigations of either growth or limits to growth with respect to product formulation or process conditions. An example of a probabilistic exposure assessment model for chilled food application is provided and its potential added value as a food safety management tool in an industrial context is weighed against its disadvantages. The role of predictive microbiology in the suite of tools available to food industry and some of its advantages and constraints are discussed.     

Predictive Microbiology Models and Operational Readiness

A diverse field of predictive microbiology models has emerged in the past 30 years and has advanced our understanding of microbial behavior in foods. As most of published models have for objective to provide operationally relevant information to decision makers, predictive microbiology models have now found their place within both the academic, and the food industrial communities.Given the importance of these models to food safety, the decision makers are in need of evidence-based advices in order to assess confidence in the predictions provided by models they use. The objectives of this work were (i) to review current approaches in predictive microbiology used to build, verify and validate models, and (ii) to propose a categorization scheme that would tend to define a model's viability for use in an operational setting.     

Engineering modeling frameworks for microbial food safety at various scales

The landscape of mathematical model-based understanding of microbial food safety is wide and deep, covering interdisciplinary fields of food science, microbiology, physics, and engineering. With rapidly growing interest in such model-based approaches that increasingly include more fundamental mechanisms of microbial processes, there is a need to build a general framework that steers this evolutionary process by synthesizing literature spread over many disciplines. The framework proposed here shows four interconnected, complementary levels of microbial food processes covering sub-cellular scale, microbial population scale, food scale, and human population scale (risk). A continuum of completely mechanistic to completely empirical models, widely-used and emerging, are integrated into the framework; well-known predictive microbiology modeling being a part of this spectrum. The framework emphasizes fundamentals-based approaches that should get enriched over time, such as the basic building blocks of microbial population scale processes (attachment, migration, growth, death/inactivation and communication) and of food processes (e.g., heat and moisture transfer). A spectrum of models are included, for example, microbial population modeling covers traditional predictive microbiology models to individual-based models and cellular automata. The models are shown in sufficient quantitative detail to make obvious their coupling, or their integration over various levels. Guidelines to combine sub-processes over various spatial and time scales into a complete interdisciplinary and multiphysics model (i.e., a system) are provided, covering microbial growth/inactivation/transport and physical processes such as fluid flow and heat transfer. As food safety becomes increasingly predictive at various scales, this synthesis should provide its roadmap. This big picture and framework should be futuristic in driving novel research and educational approaches.     

Nonthermal Processes for Shelf‐Life Extension of Seafoods: A Revisit

For the past two decades, consumer demand for minimally processed seafoods with good sensory acceptability and nutritive properties has been increasing. Nonthermal food processing and preservation technologies have drawn the attention of food scientists and manufacturers because nutritional and sensory properties of such treated foods are minimally affected. More importantly, shelf‐life is extended as nonthermal treatments are capable of inhibiting or killing both spoilage and pathogenic organisms. They are also considered to be more energy‐efficient and to yield better quality when compared with conventional thermal processes. This review provides insight into the nonthermal processing technologies currently used for shelf‐life extension of seafoods. Both pretreatments such as acidic electrolyte water and ozonification and processing technologies, including high hydrostatic pressurization, ionizing radiation, cold plasma, ultraviolet light, and pulsed electric fields, as well as packaging technology, particularly modified atmosphere packaging, have been implemented to lower the microbial load in seafood. Thus, those technologies may be the ideal approach for the seafood industry, in which prime quality is maintained and safety is assured for consumers.     

Predicting mycotoxins in foods: A review

The need to ensure the microbiological quality and safety of food products has stimulated interest in the use of mathematical models for quantifying and predicting microbial behaviour. For 20 years, predictive microbiology has been developed for predicting the occurrence of food-borne pathogens, although these tools are dedicated to bacteria. Recently, the situation has changed and a growing number of studies are available in the literature dealing with the predictive modelling approach of fungi. To our knowledge the present one is the first review focussed on predictive mycology and food safety, including mycotoxins; existing kinetic and probability models applied to mycotoxigenic fungi germination and growth, and mycotoxin production are reviewed.     

The future of predictive microbiology: strategic research, innovative applications and great expectations

This paper considers the future of predictive microbiology by exploring the balance that exists between science, applications and expectations. Attention is drawn to the development of predictive microbiology as a sub-discipline of food microbiology and of technologies that are required for its applications, including a recently developed biological indicator. As we move into the era of systems biology, in which physiological and molecular information will be increasingly available for incorporation into models, predictive microbiologists will be faced with new experimental and data handling challenges. Overcoming these hurdles may be assisted by interacting with microbiologists and mathematicians developing models to describe the microbial role in ecosystems other than food. Coupled with a commitment to maintain strategic research, as well as to develop innovative technologies, the future of predictive microbiology looks set to fulfil "great expectations".     

预测微生物学在乳品安全领域的研究进展

乳品中含有丰富的营养物质, 易被有害微生物污染, 进而影响消费者身体健康。不同乳品由于自身属性、加工条件和所处环境的不同, 被微生物污染的状况也不一样。预测微生物学可以根据微生物在乳品储藏、运输和加工技术条件下的生长存活情况, 通过建立模型, 判断其动态变化趋势, 从而帮助科研人员和生产者有效评估和控制乳品安全, 也为加工工艺改进提供信息。本文介绍了预测微生物学模型的分类及乳品安全方面常用的预测微生物学模型和数据测定方法, 阐述了预测微生物学在控制乳品微生物风险中的应用, 并针对预测微生物学在乳品安全领域应用中存在的问题进行了探讨, 展望了其未来发展方向, 旨在为保障乳品安全提供参考。     

Fluid dairy product quality and safety: looking to the future

The fiercely competitive nature of the US beverage industry will drive the fluid milk sector of the dairy industry to improve product quality and shelf life to enable dairy beverages to compete with innovative new introductions as well as with currently popular shelf-stable products. The recent substantial growth in the volume of flavored milk sales specifically suggests that attention is needed to improve these products. Further, increasing public awareness and regulatory attention directed toward food safety issues highlight the need for the dairy industry to proactively address and eliminate emerging food safety issues that may negatively impact the image of dairy products. Shelf life and sensory profiles of high temperature short time pasteurized fluid milk products are presented, illustrating the need for greater attention to controlling contaminating microorganisms in processed fluid milk products. Bacterial spoilage patterns of flavored versus unflavored milks are compared, and suggestions are presented for extending flavored product shelf lives. Strategies currently applied to extend shelf life are reviewed. Food safety issues facing the dairy industry are presented within the context of an overview of foodborne illnesses in the United States. The pressing need to determine thermal resistance characteristics of Mycobacterium paratuberculosis is described.