食品腐败中细菌群体感应现象的研究进展

微生物作用是引起食品腐败变质的主要因素之一。研究表明,细菌群体感应在该过程中起着重要作用。文中介绍了群体感应现象的产生机制与研究前沿,重点以牛奶和奶制品、肉和肉制品、水产品和果蔬4类食品体系为例分析了细菌群体感应现象在食品腐败中的作用,最后对开发以群体感应抑制剂为新型防腐剂的食品保藏新策略进行了论述,以期在为从群体感应角度研究食品腐败机制及保鲜方法提供理论依据。     

食品腐败的关键调控机制之群体感应的研究进展

群体感应是细菌之间的一种细胞密度依赖型信息交流机制,越来越多的研究证明,细菌群体感应与食品腐败变质过程之间存在复杂而紧密的联系,有望成为食品保鲜技术领域中一个极具应用前景的新靶点。本文概述了微生物群体感应、群体感应对食品腐败变质的影响和群体感应抑制剂3个方面的研究进展,重点介绍了食源细菌的群体感应研究进展和群体感应对食品(水产品、肉及肉制品、乳及乳制品和果蔬)腐败变质的影响,旨在为新型食品保鲜技术的开发提供理论指导。     

冷却猪肉特定腐败微生物与群体感应现象研究进展

冷却肉的腐败是由特定腐败菌共同作用的结果,由微生物分泌的蛋白酶、脂肪酶和脱羧酶在肉的腐败过程中起着重要作用。最终菌相决定了冷却肉的腐败类型,而最终菌相除了受到初始污染的微生物结构和数量的影响外,还受到贮藏环境和保鲜剂的影响。特定腐败菌之间主要通过拮抗、后继共生和信息交流三种方式进行相互作用,从而影响肉的腐败。大量研究表明食品腐败与特定腐败菌的群体感应有关。对群体感应系统进行干扰,阻止腐败相关基因的表达,已经成为食品保鲜的新靶点。     

食品防腐中群体感应及其抑制剂的研究进展

食品的腐败变质是食品工业长期以来一直面对的重大问题。近年来研究表明细菌群体感应(quorum sensing,QS)现象与食品腐败变质密切相关。本文简要介绍了群体感应系统和信号分子的分类,重点阐述了群体感应抑制剂(quorum sensing inhibitors,QSIs)的研究进展,并讨论了利用群体感应抑制剂控制食品腐败变质的应用前景。      

群体感应AHLs对温和气单胞菌体外致腐因子分泌的影响

以大菱鲆腐败菌温和气单胞菌(Aeromonas sobria,AS7)为研究对象,研究了不同处理方式(营养基质、共生培养和添加不同种类的AHLs)对温和气单胞菌的致腐因子(嗜铁素、胞外蛋白酶、生物被膜)产生情况的影响,结果表明,菌株AS7嗜铁素的分泌受到培养基质的影响,在脱脂牛奶等天然基质中可以大量分泌嗜铁素,而市售的合成培养基中不能分泌嗜铁素;AHLs的添加对嗜铁素的产生量有影响,其中,C8-HSL影响显著,随添加的增加,嗜铁素分泌量呈现正相关(P0.05),而C6-HSL影响不显著(P0.05);共生条件下,温和气单胞菌对荧光假单胞菌和腐败希瓦氏菌嗜铁素的分泌有明显促进作用;AHLs的添加可以促进温和气单胞菌胞外蛋白酶和生物被膜的产量,且呈现正相关(P0.05),说明AHLs对温和气单胞菌产生胞外蛋白酶、嗜铁素和生物被膜具有调控作用。     

水产品特定腐败菌群体感应及其植物源抑制剂研究进展

水产品的腐败过程主要由微生物活动引起。文章通过对水产品中的特定腐败菌、微生物的群体感应信号分子、群体感应抑制剂的来源与作用方式等进行阐述,提出当前植物源群体感应抑制剂存在的问题及解决措施。     

群体感应在食源性微生物生物膜形成中的作用

生物膜(Biofilm)是由众多微生物聚集黏附在物体表面形成的多细胞群体结构,多种食源性微生物均能形成相应的生物膜,且该现象的产生对食品加工与安全有着重要影响。群体感应(Quorum sensing,QS)已被证明是调控生物膜形成的重要因素。文章主要介绍了群体感应对几种食源性细菌及真菌生物膜形成的调控作用,旨在为食品加工过程中微生物生物膜的控制与利用提供参考。     

Growth of Salmonella enteritidis and Salmonella typhimurium in the presence of quorum sensing signalling compounds produced by spoilage and pathogenic bacteria

The effect of acylated homoserine lactones (AHLs) and autoinducer-2 (AI-2) signalling compounds present in the cell-free culture supernatants (CFS), of Pseudomonas aeruginosa, Yersinia enterocolitica-like GTE 112, Serratia proteamaculans 00612, Y. enterocolitica CITY650 and Y. enterocolitica CITY844, on the growth of two Salmonella Enteritidis and two S. Typhimurium strains was assessed though monitoring of changes in conductance of the medium. Detection times (T_det), area and slope of conductance curves were recorded. Except for P. aeruginosa 108928, which was not found to produce AI-2, all other strains produced both AHLs and AI-2. Thereafter, aliquots (20% in the final volume) of these CFS were transferred into NZ Amine broth inoculated with ca. 10³ CFU/ml of stationary phase cultures of each Salmonella strain. While the CFS of P. aeruginosa induced a shorter detection time, i.e. acceleration of the metabolic activity, the CFS of the other microorganisms increased the detection time of Salmonella strains compared to control samples (i.e. without CFS). Results indicate that the growth of Salmonella may be affected by the presence of Quorum sensing (QS) signalling compounds and/or other novel signals existing in CFS, produced by other bacterial species and confirm the complexity of bacterial communication.     

Physiology of food spoilage organisms.

A thorough understanding of the physiological responses of microorganisms to stresses imposed during food preservation is essential if novel combination systems based on mild food processing procedures are to be developed effectively. The influences of intrinsic characteristics as well as external factors such as water activity, temperature, preservatives, composition of the gaseous atmosphere, etc. on the stress response of microorganisms are discussed. The interaction of spoilage organisms with each other as well as with food pathogens and the ultimate consequences for food safety and quality are also explored in this review.     

黄曲霉群体感应研究进展

曲霉属真菌(Aspergillus)如黄曲霉、寄生曲霉侵染玉米、花生等富含油脂的作物种子后产生的黄曲霉毒素(aflatoxin)具有强致癌作用,严重威胁食品安全和人类健康。群体感应(quorum sensing,QS)曾经认为只存在于细菌中,但是在真菌中也存在QS系统,菌体的形态建成和次级代谢产物的产生都与细胞的群体密度有关。黄曲霉拥有类似群体感应的机制,菌核到分生孢子的转换受细胞密度和脂肪氧合酶调控。氧脂素作为信号分子通过密度依赖机制可抑制或促进黄曲霉的生长及黄曲霉毒素的生物合成,本文综述了黄曲霉群体感应及信号通路的研究进展,旨在从群体感应的角度抑制黄曲霉毒素的产生,为微生物与食品安全的研究提供指导。     

乳酸菌群体感应的研究进展

乳酸菌的益生特性已引起公众的广泛关注。群体感应是细菌感受外界环境变化并做出反应的转导机制,对乳酸菌的存活及益生特性至关重要。因此,近些年来乳酸菌的群体感应成为研究热点。该文综述了乳酸菌群体感应的信号分子及其双组分系统,群体感应对乳酸菌环境适应的调控（生物膜、耐酸、耐胆盐）,群体感应对乳酸菌益生特性（抑制致病菌、与宿主相互作用）的影响以及实际应用,为乳酸菌群体感应今后的基础研究和工业化应用提供参考。     

Chemoprevention: Insights into biological mechanisms and promising food factors

Abstract

Chemoprevention with food phytochemical is currently regarded as one of the noticeable scientific fields. A large body of data from epidemio‐logic and rodent studies has demonstrated that ingestion of vegetables and fruits is occasionally beneficial for reduction of cancer risks in humans. Recent clinical trials using ubiquitous antioxidants such as α‐carotene, however, have yet to show their cancer preventive effect despite the fact that they have been reported to be chemopreventive agents in rodent models. One of the goals of this review is to address useful and reliable methodology to detect promising chemopreventive agents from edible plants by highlighting molecular mechanisms of multistage carcinogenesis.     

细菌共培养及其系统中群体感应现象的研究进展

本文对微生物的共培养方式、分类、发展及应用进行了简介,并对不同种属的微生物共培养后产生的作用进行了综述。微生物共培养系统不仅受到协同代谢作用的调控,群体感应在微生物共培养中也扮演着重要的角色。与纯培养相比,共培养体系生物被膜的形成、信号分子和毒力因子的产生、细菌素的合成以及胞外蛋白酶的分泌等都有所不同。研究群体感应的作用机理有助于共培养技术的进一步发展与应用。      

一类具有群体感应机理的传染病模型渐近分析

考虑病菌的群体感应机理,建立了一类具有一般作用率反应病菌与免疫系统竞争的传染病数学模型. 分析了模型平衡点的存在性及渐近稳定性. 特别地,利用中心流形定理研究退化平衡点的稳定性. 最后,数值模拟验证所得理论结果,为传染病的控制和预防提供了理论基础和数值依据.     

Analysis of the inhibition of food spoilage yeasts by vanillin

The antimicrobial potential of vanillin, the major component of vanilla flavour, was examined against the growth of three yeasts associated with food spoilage, Saccharomyces cerevisiae, Zygosaccharomyces bailii and Zygosaccharomyces rouxii. Minimum inhibitory concentration (MIC) values of 21, 20 and 13 mM vanillin were determined for the three yeast strains, respectively. The observed inhibition was found to be biostatic. During fermentation, the bioconversion of sub-MIC levels of vanillin in the culture medium was demonstrated. The major bioconversion product was identified as vanillyl alcohol, however low levels of vanillic acid were also detected. Neither the vanillyl alcohol nor the vanillic acid was found to be antagonistic to yeast cell growth. The results indicate the importance of the aldehyde moiety in the vanillin structure regarding its antimicrobial activity and that the bioconversion of vanillin could be advantageous for the yeasts, but only at levels below MIC. These bioconversion activities, presumably catalysed by non-specific dehydrogenases, were shown to be expressed constitutively. It was observed that increased vanillin concentrations inhibited its own bioconversion suggesting that the activity required intact cells with metabolic capacity.     

食品腐败相关气体检测研究进展

食品在贮藏、运输和销售等环节中由于本身的酶促反应以及微生物的污染,容易发生腐败变质,不仅降低了食品的营养价值,而且其产生的腐败微生物及毒素等多种有毒有害物质也会对食品安全造成严重威胁,因此食品腐败检测对于降低食品安全风险具有重要意义。而食品腐败检测因其方法技术的限制,目前仍是食品安全领域极具挑战性的难题之一。检测食品腐败过程中产生的特征气体的技术方法具有便捷、高效、无损等优点,因此成为了当前食品腐败检测研究领域的热点。本文将对气体检测在食品腐败检测中的最新进展进行综述,对比色法、荧光、电子鼻以及电化学传感方法进行分类总结,重点阐述纳米材料传感在气体检测中的应用,及其与物联网、机器学习相结合的辅助分析方法,展望了气体检测在食品腐败检测行业中的发展趋势和即将面临的挑战,为食品腐败检测中气体检测的研究提供参考和启发。