肉类食品的保鲜技术

腐败微生物的大量增殖，是造成肉类食品腐败的主要原因，防腐保鲜的基本原理主要是在尽可能减少肉类食品中微生物殖留量的基础上，抑制肉类食品中微生物的生长代谢和酶的活性。综述了传统的肉类保鲜技术与现代防腐技术。     

肉类食品的保鲜技术

腐败微生物的大量增殖,是造成肉类食品腐败的主要原因,防腐保鲜的基本原理主要是在尽可能减少肉类食品中微生物残留量的基础上,抑制肉类食品中微生物的生长代谢和酶的活性.综述了传统的肉类保鲜技术与现代防腐技术.     

影响肉类凉菜即食包装制品易腐性的因素

引起肉类凉菜即食包装制品腐败变质的易腐性因素包括固有酶的作用、理化因素的作用、空气和微生物等。肉类凉菜即食包装制品腐败变质的主要原因是微生物分解即食包装制品食物中的蛋白质和氨基酸。肉类凉菜即食包装制品原料中存在具有催化活性的酶类,在加工、贮藏过程中引发腐败。温度、光照、含水量也是诱发腐败变质的因素,温度升高会引起食品成分的化学变化,有利于微生物的繁殖。     

新鲜肉类的辐照加工技术

食品辐照是一种较为先进的食品保鲜贮存技术 ,通过减少或清除肉类食品中的传染性病菌 ,能提高新鲜肉类的食用安全性 ;同时 ,延长了肉类食品保鲜期。经试验证明 ,辐照加工不会对鲜肉原有的质量产生不良影响。1　微生物的减少与清除电离辐照对存在于肉类食品中的微生物 ,如细菌、酵母、霉菌等均有一定的破坏作用。通过损害微生物细胞体内的遗传物质 ,我们可以阻止这些遗传物质进行细胞生长所必须经历的生化过程 ,从而阻碍微生物的繁殖。在一般情况下 ,辐照处理可以减少或清除那些导致新鲜肉类食品腐败变质的微生物和病菌 ;在实际应用中 ,于低…     

肉类腐败微生物

肉类腐败微生物来源于环境、肉类本身、贮藏、加工及销售等过程,肉类的腐败变质导致其商品和消费价值降低或者消失,主要与其中的优势菌有关。采用现代技术手段可以抑制微生物的繁殖,保证肉类产品的品质,延长货架期。     

肉类微生物学(九) 肉类微生物的控制

肉类的腐败变质主要是由微生物引起的,本文主要介绍了肉类微生物控制的三个基本策略,即防止微生物的生长、杀死微生物、促进有益微生物的生长,使其抑制有害微生物的生长,并重点介绍了各种不同的控制措施。     

肉类微生物学(三) 肉中革兰氏阴性食源性致病菌

肉类是人们日常生活中必不可少的食品,但因其营养丰富极易受到微生物的污染而发生腐败变质,降低其食用价值和商品价值,缩短其货架期并增加食源性疾病的危害,因此肉类的安全越来越引起人们的关注。本文主要针对肉中的G-食源性致病菌的食品卫生学意义、生物学特性、流行病学特性、检验以及相应的预防措施进行了综述。     

微生物与肉类腐败变质

本文介绍了腐败肉的特征、分类以及引起肉类腐败变质的原因与条件,其中以微生物引起的腐败最为普遍,因此,本文重点介绍了导致肉类腐败变质的微生物的种类及特性,以及如何防止肉的腐败变质。     

微生物与肉类腐败变质

微生物污染导致肉类腐败变质,如何防范和鉴别肉类腐败变质,本文分析了肉类中微生物的来源、肉类腐败引起的变化和现象,为人们提供了防范意识和鉴别方法。     

肉类微生物学(八)肉类腐败菌

鲜肉和大多数的肉制品都极易变质。一般来说,在动物屠宰放血之后,从由肌肉向肉的转化阶段开始,肉就受到各种微生物、化学和物理因素的作用,进入腐败变质过程。其中以微生物引起的腐败最为普遍,尤其是细菌。因此,本文重点介绍了导致肉类腐败变质的细菌的种类、特性以及各种食品中的腐败细菌。     

The microbiology of DFD fresh meats: A review

Muscle which is deficient in glycogen because of exercise or stress prior to slaughter produces dark, firm, dry (DFD) meat. Such meat is characterized by a high ultimate pH (>6·0) and deficiencies in glucose and glycolytic intermediates. These factors can result in bacterial spoilage becoming evident at an early stage of growth of the meat flora. Spoilage becomes apparent when bacteria attack amino acids. This does not occur under aerobic conditions until bacteria exhaust the glucose at the meat surface. However, since glucose is absent in DFD meat, amino acids are utilised without delay and spoilage becomes evident at lower cell densities than in normal meat. The absence of glucose also allows the anaerobic flora to produce spoilage odours at an early stage. Additionally, the high pH of DFD meat allows growth of potent spoilage organisms which are inhibited at the usual ultimate pH of meat. Early aerobic spoilage can be prevented by the addition of glucose, but prevention of early anaerobic spoilage requires the addition of a citrate buffer which reduces the surface pH, as well as providing a carbohydrate substrate which is utilised in preference to amino acids. Comparisons can be made between spoilage of DFD red meat and spoilage of white meats from poultry and fish, which normally have a high ultimate pH.     

冷却肉微生物腐败与冷链系统

冷却肉极易发生微生物腐败,温度是最关键的影响因素。冷链系统持续的低温能抑制微生物的生长繁殖,预防冷却肉腐败。本文简述了微生物代谢活动对冷却肉腐败的影响,重点将冷链系统分为加工冷链、运输冷链、销售冷链和家庭保藏四部分,分别从概念及存在的问题等方面加以阐述,并展望了其未来有待提高完善的地方。     

A preliminary study of the effect of urea in the preservation of meat

An investigation was undertaken on the effect of urea in the preservation of meat. It was observed that there was always a lag period in the early stages of microbial spoilage of meats at different temperatures, due to the non-availability of required nutrients, and subsequent rapid growth of microorganisms was attributed to the utilisation of amino acids released due to autolytic changes. Dry urea salt was employed in the present study to denature or retard the activity of enzymes of the meat in order to extend the shelflife of meat by preventing spoilage. Parameters such as ERV, pH and TPC were studied during meat spoilage. It appears from the present studies that autolytic changes were responsible for the ultimate spoilage of meat. When urea was applied in the meat, the microbial lag phase and the shelflife of meat were extended. It seems that urea checked the autolytic changes in meat and thereby microbial growth was delayed due to the non-availability of nutrients from the autolytic changes.     

The Predominance of Psychrotrophic Pseudomonads on Aerobically Stored Chilled Red Meat

Microbial spoilage of meat during chilled aerobic storage causes significant financial losses to the industry. Even with modern day preservation techniques, spoilage remains an unsolved problem. Spoilage of meat is a complex process that involves the activity of endogenous enzymes and microorganisms. Psychrotrophic Pseudomonas species are the key microorganisms that cause spoilage in aerobically stored chilled meat. Spoilage pseudomonads are highly robust and able to withstand stressful environmental conditions that would otherwise inhibit the growth of other spoilage organisms. In order to implement efficient control measures, and to minimize spoilage, a thorough understanding of the characteristics of spoilage pseudomonads is essential. This review focuses on the spoilage process and the key metabolic attributes of the main psychrotrophic spoilage Pseudomonas species to explain their predominance on meat over other psychrotrophic bacteria. This review also highlights less studied, but important, characteristics of psychrotrophic pseudomonads such as biofilm formation and quorum sensing in the context of meat spoilage. The importance of the use of model systems that are closely applicable to the food industry is also discussed in detail.     

Behaviour of Brochothrix thermosphacta in presence of other meat spoilage microbial groups

The microbial flora of fresh meat stored aerobically at 5 degrees C up to spoilage was enumerated and collected in order to have mixed spoilage bacterial groups to be used in competition tests against Brochothrix thermosphacta. The bacterial groups collected as bulk colonies were identified by PCR-DGGE followed by partial 16S rDNA sequencing. The predominant bacteria associated with the spoilage of the refrigerated beef were B. thermosphacta, Pseudomonas spp, Enterobacteriaceae and lactic acid bacteria (LAB). The interactions between B. thermosphacta and the other spoilage microbial groups were studied in vitro at 5 degrees C. The results showed that a decrease of the growth of B. thermosphacta was evidenced in presence of LAB at 5 degrees C while the bacterium is the dominant organism when inoculated with mixtures of Pseudomonas spp., LAB and Enterobacteriaceae. A better understanding of bacterial meat spoilage interactions may lead to improved quality of fresh meat stored in refrigerated conditions.     

羊肉微生物相调查及山梨酸钾的防腐作用

7组样品统计分析表明,羊肉微生物相主要有8种类型的革兰氏阳性菌和阴性菌组成;从中选取5株代表性菌株并用山梨酸钾对其进行抑菌试验,结果表明,0.25‰以上山梨酸钾能够有效抑制105cfu/ml革兰氏阳性短芽孢杆菌和革兰氏阴性短杆菌的生长。     

The ecology of bacterial spoilage of fresh meat at chill temperatures

At chill temperatures the spoilage flora of meat is composed of psychrotrophs originating largely from the hides of slaughtered animals. Under humid conditions, aerobic floras are usually dominated by pseudomonads while anaerobic floras are dominated by lactobacilli. In both cases growth occurs on low molecular weight soluble components of meat which are attacked in the order glucose, glucose-6-phosphate (Enterobacteriaceae only) and amino acids. Under aerobic conditions spoilage becomes detectable when the bacteria begin to degrade amino acids which remain abundant at the meat surface when growth ceases, probably because of limited availability of oxygen. Under anaerobic conditions growth ceases because the diffusion of fermentable substrates to the surface is not rapid enough to support further growth. Aerobically, there is no interaction between different bacterial species until the maximum cell density is approached; anaerobically, however, lactobacilli produce an antimicrobial agent which inhibits growth of competing species. The composition of spoilage floras can be affected by changes in water activity and the storage atmosphere.     

Psychrophilic and psychrotrophic clostridia: sporulation and germination processes and their role in the spoilage of chilled,vacuum‐packaged beef,lamb and venison

Spoilage of beef, lamb and venison by psychrophilic and psychrotrophic clostridial species renders meat unacceptable resulting in financial losses and reduced consumer confidence. A number of clostridial strains, including Clostridium algidicarnis, Clostridium algidixylanolyticum, Clostridium estertheticum, Clostridium frigidicarnis and Clostridium gasigenes, have been implicated in red meat spoilage. Unlike other spoilers, these clostridia are able to grow in anaerobic conditions and at chilled temperatures (some at ?1.5 °C the optimal storage temperature for chilled red meat). The spoilage they cause is characterised by softening of the meat, production of large amounts of drip (exudates), offensive odours and in the case of C. estertheticum and C. gasigenes production of gas. Spoilage occurs following the introduction of clostridial spores into vacuum packages during processing. Germination of spores is necessary for the growth of vegetative cells, which cause spoilage. Current mitigation strategies focus on good management practice within meat processing plants. However, this is not always sufficient to prevent spoilage. This review summarises the issues associated with meat spoilage because of psychrotolerant clostridia and discusses areas that require further study.     

冷却肉特定腐败菌群体感应的研究进展

微生物引起的腐败变质是影响肉品质量安全的重要因素。研究表明,细菌群体感应（quorum sensing,QS）与肉类腐败变质密切相关。群体感应抑制剂（quorum sensing inhibitor,QSI）通过阻断QS信号的合成或传递,降低细菌致腐性,成为肉品保鲜技术领域极具应用前景的新靶点。本文概述了微生物的QS现象、QS对肉品腐败变质的影响以及QSI的来源、特性和作用机制,并提出利用QS调控肉品腐败变质存在的问题和应用前景。