食源性混合菌生物被膜的形成和相互作用机制

在食品加工中,食源性病原菌生物被膜的存在会引发大量食品污染等安全问题。目前,国内外学者深入研究了单一菌生物被膜,然而对混合菌生物被膜的研究较少。本文在现有的研究基础上,归纳总结了食源性混合菌生物被膜的形成规律及混合菌生物膜中菌种间的相互作用,初步探讨了群体感应在混合菌生物膜中的作用,以期为食品领域应对和破解食源性混合菌生物被膜污染问题提供思路。     

食品接触表面对金黄色葡萄球菌生物被膜形成的影响

在食品工业中,如果金黄色葡萄球菌粘附在食品接触表面并形成生物被膜,不但会造成设备的腐蚀,更重要的是会污染食品,影响了食品的安全性.生物被膜形成的第一步是微生物在食品接触表面的粘附.本文研究了4种不同食品接触表面对金黄色葡萄球菌生物被膜形成的影响.结果表明：与玻璃和PE塑料相比,不锈钢表面粘附形成生物被膜的活菌数较多.不同的食品接触表面影响了生物被膜的形成.     

三种食品添加剂抑制菌体生物被膜形成

为探索有效手段清除生物被膜,作者采用二倍稀释法研究茶多酚、柠檬醛、肉桂醛对金黄色葡萄球菌、沙门氏菌以及大肠杆菌的最小抑菌浓度。并在亚致死浓度下,利用微孔板法研究此3种天然产物抑制3种细菌及其混合菌的生物被膜形成以及群体感应信号分子AI-2的情况。结果表明,在亚抑菌浓度下,茶多酚对金黄色葡萄球菌生物被膜抑制效果最好,肉桂醛对大肠杆菌和沙门氏菌的生物被膜抑制效果最好,而柠檬醛对所有细菌及其混合菌AI-2活力都具有抑制效果。     

食源性混合菌种生物被膜的形成与种间相互作用

食源性微生物形成的生物被膜是食品生产加工中不容忽视的安全隐患,针对食品生产加工环境中广泛存在的混合菌种生物被膜的研究仍处于起步阶段。该文在现有的理论和研究结果基础上,总结了食源性混合菌种生物被膜的形成规律,归纳介绍了混合被膜中微生物间以竞争和共生为主的种间相互作用及其调控机制,旨在为食品领域混合菌种生物被膜的研究提供借鉴。     

腐败牛奶中三种细菌生物被膜特性探究

生物被膜的形成给牛奶保藏和保鲜带来极大的隐患,探讨牛奶腐败过程中生物被膜形成特性以及寻求有效的抑制生物被膜的方法具有重要意义。本实验通过微孔板法模拟牛奶腐败过程,研究食源性金黄色葡萄球菌、肠炎沙门氏菌和大肠杆菌在牛奶中生物被膜形成能力、生物被膜中活菌数目与种间群体感应信号分AI-2活力三者之间的关系。随后利用AI-2抑制剂呋喃酮,检测三种细菌生物被膜形成能力及AI-2活力变化。最后证明,三种细菌生物被膜形成能力、生物被膜中活菌数目以及AI-2活力顺序均是金黄色葡萄球菌大肠杆菌沙门氏菌。添加呋喃酮之后,三种细菌的生物被膜形成能力以及AI-2活力均下降,其中金黄色葡萄球菌的生物被膜形成能力下降为原来的25%。因此表明,此三种细菌生物被膜形成能力的大小可能是是通过调节生物被膜中AI-2的活力实现的。     

食源性混合病原菌生物被膜行为对金黄色葡萄球菌毒素因子转录水平的影响

以食源性病原菌(金黄色葡萄球菌、大肠杆菌和肠炎沙门氏菌)形成的混合菌生物被膜为研究对象,对其定性和定量检测,通过实时荧光定量PCR方法分别检测单一菌和混合菌生物被膜中金黄色葡萄球菌28种目的毒素基因转录水平的变化。结果表明,结晶紫染色法、银染法和扫描电镜法均表明混合菌在培养24 h时达到最大黏附度;混合菌生物被膜中3种细菌的活菌数均低于单菌生物被膜中的活菌数;28种毒素基因在金黄色葡萄球菌中均被检出,且混合菌相对于单一菌生物被膜,上调量显著的有肠毒素基因sep、ser,显著下降的有溶血素基因hla和脱皮毒素基因etd,肠毒素基因seb表达量相等。     

等离子体活化水在食品工业中应用研究进展

等离子体活化水(Plasma-activated water,PAW)具有活性组分含量高、低pH和氧化还原电位较高等特点,具有杀菌、抗生物被膜、促进种子萌发和幼苗生长等功能。作为一种新型的环境友好型非热加工技术,PAW在食品工业中的潜在应用前景受到广泛关注。本文综述了PAW在食品杀菌保鲜、肉制品护色、细菌生物被膜控制等领域中的应用研究,为PAW技术在食品工业中的广泛应用提供参考。     

食品加工过程中细菌生物被膜的危害及控制

生物被膜中的微生物生活在一个由胞外聚合物（EPS）形成的环境中,它的形成是微生物生长过程中的一个保护模式,允许细胞在恶劣的环境中生存并分散到新的环境中。食品加工过程中有害菌形成的生物被膜对食品工业的危害极大,可使微生物残存增加,加工设备无法严格清洗、消毒,导致产品受到污染。该文在收集、研究现有文献的基础上归纳介绍了生物被膜的特点及其形成过程和形成机制,概述了生物被膜的危害、控制及检测方法,旨在提高人们对生物被膜的认识,推动该领域的研究发展。     

群体感应系统及其抑制剂对细菌生物被膜调控的研究进展

细菌生物被膜是细菌附着在生物或非生物体表面形成的多细胞群落,对机械干扰、宿主防御以及抗生素具有很强的抵抗力,是引起慢性感染的主要原因。群体感应(quorum sensing,QS)是细菌某些基因的表达受到与群体密度相关信号分子调控的现象,在调控细菌生物被膜的形成过程中发挥着至关重要的作用。因此,利用QS抑制剂(quorum sensing inhibitors,QSI)干扰这种调控作用为控制细菌生物被膜的危害提供了重要的方法。本文以铜绿假单胞菌、金黄色葡萄球菌和大肠杆菌为例,综述QS系统在调控细菌生物被膜形成过程中的重要作用,介绍QSI通过抑制信号分子合成、酶解信号分子以及干扰信号分子与受体结合等作用途径,干扰细菌生物被膜的形成,以期为细菌生物被膜慢性感染的预防和治疗开辟新路径提供参考。     

细菌生物被膜检测与清除方法研究进展

开展食源性致病菌的防控研究以保障食品安全,具有显著的实践意义。作为细菌为适应不良环境所表现出的一种自我保护机制,食源性致病菌在食品生产加工过程中,可以黏附在食品原材料表面以及各种食品加工器械表面形成生物被膜,增大了消毒清洗的难度,给食品安全带来了严重的隐患和危害。因此,如何有效地清除细菌生物被膜成为食品安全领域的研究热点。结合细菌生物被膜形成过程和调控机制,本研究系统分析总结了细菌生物被膜的检测与清除方法的现状,为实现细菌生物被膜的有效控制,消除由生物被膜造成的食品安全隐患提供了综合性的认识,可为研究人员解决细菌生物被膜带来的食源性微生物污染提供参考,对保障食品安全有重要意义。     

Mixed-species biofilms in the food industry: Current knowledge and novel control strategies

Abstract

Attachment of microorganisms to food contact surfaces and the subsequent formation of biofilms may cause equipment damage, food spoilage and even diseases. Mixed-species biofilms are ubiquitous in the food industry and they generally exhibit higher resistance to disinfectants and antimicrobials compared to single-species biofilms. The physiology and metabolic activity of microorganisms in mixed-species biofilms are however rather complicated to study, and despite targeted research efforts, the potential role of mixed-species biofilms in food industry is still rather unexplored. In this review, we summarize recent studies in the context of bacterial social interactions in mixed-species biofilms, resistance to disinfectants, detection methods, and potential novel strategies to control the formation of mixed-species biofilms for enhanced food safety and food quality.     

Biofilms in the Spotlight: Detection,Quantification, and Removal Methods

Microorganisms can colonize and subsequently form biofilms on surfaces, which protect them from adverse conditions and make them more resistant than their planktonic free‐living counterparts. This is a major concern in the food industry because the presence of biofilms has significant implications for microbial food contamination and, therefore, for the transmission of foodborne diseases. Adequate hygienic conditions and various preventive and control strategies have consequently been developed to ensure the provision of safe, good‐quality food with an acceptable shelf‐life. This review focuses on the significance of biofilms in the food industry by describing the factors that favor their formation. The interconnected process among bacteria known as “quorum sensing,” which plays a significant role in biofilm development, is also described. Furthermore, we discuss recent strategic methods to detect, quantify, and remove biofilms formed by pathogenic bacteria associated with food processing environments, focusing on the complexity of these microbial communities.     

Promising strategies to control persistent enemies: Some new technologies to combat biofilm in the food industry—A review

Biofilm is an advanced form of protection that allows bacterial cells to withstand adverse environmental conditions. The complex structure of biofilm results from genetic-related mechanisms besides other factors such as bacterial morphology or substratum properties. Inhibition of biofilm formation of harmful bacteria (spoilage and pathogenic bacteria) is a critical task in the food industry because of the enhanced resistance of biofilm bacteria to stress, such as cleaning and disinfection methods traditionally used in food processing plants, and the increased food safety risks threatening consumer health caused by recurrent contamination and rapid deterioration of food by biofilm cells. Therefore, it is urgent to find methods and strategies for effectively combating bacterial biofilm formation and eradicating mature biofilms. Innovative and promising approaches to control bacteria and their biofilms are emerging. These new approaches range from methods based on natural ingredients to the use of nanoparticles. This literature review aims to describe the efficacy of these strategies and provide an overview of recent promising biofilm control technologies in the food processing sector.     

A review of current and emergent biofilm control strategies

Microbial adhesion to surfaces and the consequent biofilm formation has been documented in many different environments. Biofilms constitute a protected mode of growth that allows microorganisms to survival in hostile environments, being their physiology and behavior significantly different from their planktonic counterparts. In dairy industry, biofilms may be a source of recalcitrant contaminations, causing food spoilage and are possible sources of public health problems such as outbreaks of foodborne pathogens. Biofilms are difficult to eradicate due to their resistant phenotype. However, conventional cleaning and disinfection regimens may also contribute to inefficient biofilm control and to the dissemination of resistance. Consequently, new control strategies are constantly emerging with main incidence in the use of biosolutions (enzymes, phages, interspecies interactions and antimicrobial molecules from microbial origin).The present review will focus on describing the mechanisms involved in biofilm formation and behavior, deleterious effects associated with their presence, and some of the current and emergent control strategies, providing new insight of concern for food industry.     

New trends in the development of photodynamic inactivation against planktonic microorganisms and their biofilms in food system

The photodynamic inactivation (PDI) is a novel and effective nonthermal inactivation technology. This review provides a comprehensive overview on the bactericidal ability of endogenous photosensitizers (PSs)-mediated and exogenous PSs-mediated PDI against planktonic bacteria and their biofilms, as well as fungi. In general, the PDI exhibited a broad-spectrum ability in inactivating planktonic bacteria and fungi, but its potency was usually weakened in vivo and for eradicating biofilms. On this basis, new strategies have been proposed to strengthen the PDI potency in food system, mainly including the physical and chemical modification of PSs, the combination of PDI with multiple adjuvants, adjusting the working conditions of PDI, improving the targeting ability of PSs, and the emerging aggregation-induced emission luminogens (AIEgens). Meanwhile, the mechanisms of PDI on eradicating mono-/mixed-species biofilms and preserving foods were also summarized. Notably, the PDI-mediated antimicrobial packaging film was proposed and introduced. This review gives a new insight to develop the potent PDI system to combat microbial contamination and hazard in food industry.     

A review of microbial biofilms of produce: Future challenge to food safety

Outbreaks of produce-related food-borne pathogens have undergone a sharp increase in last three decades because of high produce consumption. A paradigm of food safety for produce is important due to its susceptibility to microbial attack and biofilms formation. Greater attention should be paid to decontaminating the pathogens in biofilms as they pose a risk to public health. This review will focus on produce-related outbreaks, attachments, quorum sensing, biofilms formation, resistance to sanitizers and disinfectants, and current and emerging control strategies for fresh and minimally processed produce, providing new insight into food safety. The consequences of biofilms formation on produce include the formation of a protective environment that is resistant to cleaning and disinfection. Alternative means of controlling or inhibiting biofilms formation on produce will be explained briefly and we will identify where additional research is needed.     

Removal of Salmonella enterica serovar Typhimurium and Cronobacter sakazakii biofilms from food contact surfaces through enzymatic catalysis

Bacterial biofilms are highly difficult to control, hence significant economic resources have been allocated to develop strategies to eradicate them. This study evaluated the effect of an enzymatic treatment to be used as a cleaning product to control the presence of biofilms. Two different materials used in the food industry, polystyrene and stainless steel, were tested using Salmonella Typhimuirum and Cronobacter sakazakii. Biofilm formation was carried out by inoculating the surfaces with a standardized concentration of 4 log (CFU cm⁻²) and incubated for 48 hr with renewal of nutrients. The biofilm formation and subsequent enzymatic treatment were quantified using fluorescence microscopy and the conventional culture method. The enzymatic treatment showed significant reductions of 2–3 log (CFU cm⁻²) in biofilm cells, which was attributed to the degradation of the extracellular matrix and the further detachment of both microorganisms. The maximum biofilm detachment obtained with the preventive formula was 46.67%; however, this percentage could be increased by applying an aggressive treatment or by adding a subsequent disinfection step that would eliminate adhered microbial cells. Further, the enzymatic cleaning treatment could be exploited as a potent technology to control bacterial adherence and biofilm formation in the food industry.     

葡萄柚籽提取物及其纳米乳对大肠杆菌和金黄色葡萄球菌生物菌膜的抑制作用

目的：研究葡萄柚籽提取物(grapefruitseedextract,GSE)及其纳米乳(grapefruitseedextract nanoemulsion,GNE)对大肠杆菌和金黄色葡萄球菌生物菌膜的抑制作用。方法：分析菌膜黏附菌数变化、胞外聚合物(extracellular polymeric substances,EPS)含量并进行微观结构观察,比较GSE和GNE对两菌菌膜(单种菌膜和混合菌膜)形成的抑制作用和已形成菌膜的清除效果。结果：与对照组相比,1/2最小抑菌浓度(minimum inhibitory concentration,MIC)GSE和GNE可以抑制两菌单种菌膜形成时黏附菌和EPS产生,且对金黄色葡萄球菌的抑制作用更强。扫描电子显微镜(scanning electron microcopy,SEM)和共聚焦激光扫描显微镜(confocal laser scanning microscope,CLSM)所观察到的微观结构变化也显示出GSE和GNE对两菌菌膜形成具有抑制作用。GSE和GNE对已形成菌膜也有良好清除效果,且对金黄色葡萄球菌菌膜的清除作用更强,但混合菌膜...     

四种不同接触表面蜡样芽孢杆菌菌膜形成的影响

为了解食源性致病菌蜡样芽孢杆菌在食品加工环境中菌膜形成能力,以玻璃、不锈钢、聚氯乙烯、聚丙烯为接触面,采用超声波平板菌落计数法测定不同环境因素(温度、pH、氯化钠、葡萄糖、苯甲酸钠及山梨酸钾)、不同材料表面蜡样芽孢杆菌(B.cereus)菌膜形成的变化趋势。结果表明:四种材质表面形成B.cereus菌膜能力的大小顺序为:玻璃 > 不锈钢 > 聚氯乙烯 > 聚丙烯。其中,30 ℃,pH7.0时菌膜形成量最大,添加低浓度葡萄糖(4.0%)或氯化钠(0.5%)对B.cereus菌膜形成有显著促进作用(p<0.05),添加0.15%苯甲酸钠、山梨酸钾的菌膜形成量显著高于添加0.10%的菌膜形成量(p<0.05)。本研究为蜡样芽孢杆菌风险评估提供基础数据,为食品工业蜡样芽孢杆菌菌膜的预防和控制奠定基础,为改进蜡样芽孢杆菌的清洗控制措施提供参考。