群体感应系统在乳酸菌产细菌素中的作用

许多乳酸菌能够产生抗菌活性肽——细菌素,细菌素具有不同的结构、作用方式、抑菌谱和效价,通常认为乳酸菌和其所产的细菌素都是安全的,乳酸菌所产细菌素作为天然食品防腐剂已显示了巨大的潜能。基于群体感应的细胞间交流已成为细菌素合成的关键调控机制,群体感应作为细胞密度函数,可使细菌素产生保持同步性。群体感应需通过信号分子介导感知菌体密度,信号分子随着菌体密度增加而增加,并激活信号转导级联使菌体产生细菌素。本文通过对乳酸菌群体感应信号分子种类、信号转导机制及群体感应系统对两类细菌素合成的调控进行综述,以初步了解群体感应系统在乳酸菌产细菌素过程中的作用机制。     

Application of bacteriocins in vegetable food biopreservation

Bacteriocins are generally recognized as "natural" compounds able to influence the safety and quality of foods. In the past years, a lot of works have been aimed to the detection, purification and characterisation of bacteriocins, as well as to their use in food preservation strategies. A list of review articles dealing with the application of bacteriocins to the protection of foods of animal origin is also available in literature, but it lacks for a summary on the utilization of bacteriocins in vegetable foods. These biopreservatives can be used in a number of ways in food systems and this paper mainly focuses on the state-of-the-art application of bacteriocins from lactic acid bacteria (LAB) to promote the microbial stability of both fermented and non-fermented vegetable food products using bacteriocinogenic strains as starter cultures, protective cultures or co-cultures and the employment of pure bacteriocins as food additives. In addition, applications of bacteriocins from non-LAB are also reviewed. The scopes of future directions of research are summarised.     

乳酸菌细菌素抑菌特性及在食品中的应用研究进展

乳酸菌细菌素是细菌在核糖体上合成的具有抗菌活性的多肽类物质,这些细菌素能杀灭或抑制引起食品腐败的细菌的繁殖,可作为天然的食品防腐剂在食品中应用。该文综述了乳酸菌细菌素的分类、国内外研究现状、抑菌特性及应用等方面的最新研究进展,并对乳酸菌细菌素未来研究趋势进行简要分析,对乳酸菌细菌素在食品中的应用有一定参考价值。     

Lactobacillus salivarius: Bacteriocin and probiotic activity

Lactic acid bacteria (LAB) antimicrobial peptides typically exhibit antibacterial activity against food-borne pathogens, as well as spoilage bacteria. Therefore, they have attracted the greatest attention as tools for food biopreservation. In some countries LAB are already extensively used as probiotics in food processing and preservation. LAB derived bacteriocins have been utilized as oral, topical antibiotics or disinfectants. Lactobacillus salivarius is a promising probiotic candidate commonly isolated from human, porcine, and avian gastrointestinal tracts (GIT), many of which are producers of unmodified bacteriocins of sub-classes IIa, IIb and IId. It is a well-characterized bacteriocin producer and probiotic organism. Bacteriocins may facilitate the introduction of a producer into an established niche, directly inhibit the invasion of competing strains or pathogens, or modulate the composition of the microbiota and influence the host immune system. This review gives an up-to-date overview of all L. salivarius strains, isolated from different origins, known as bacteriocin producing and/or potential probiotic.     

Development of Wide-Spectrum Hybrid Bacteriocins for Food Biopreservation

The food industry demands new procedures and methods to produce minimally processed, ready to eat food with intact nutritional, taste, and flavor properties. The biopreservation and the use of both bacteriocins produced by lactic acid bacteria (LAB) and bacteriocinogenic strains as an alternative to substitute chemical antimicrobial for food preservation became increasingly important in the last two decades. When the new proposed natural preservatives techniques are applied, probiotics food can be obtained and, simultaneously, foodborne pathogens and spoilage contaminants can diminish. However, bacteriocins produced by LAB have a narrow antibacterial spectrum and are inactive against Gram-negative bacteria like Salmonella and the emergent enterohemorrhagic Escherichia coli. Knowing the mechanism of action and the structural features of microcins synthesized by Gram-negative bacteria and with potent antimicrobial activity against the mentioned microorganism, the proposal is to obtain hybrid peptides (microcin–bacteriocin) with broad antimicrobial spectrum. This review explains how the inability of bacteriocins to cross the outer membrane of Gram-negative bacteria unable them to act on the bacteria. It will also be discussed how a hybrid bacteriocin can be obtained.     

FUNDAMENTALS AND PERSPECTIVES FOR THE USE OF BACTERIOCINS PRODUCED BY LACTIC ACID BACTERIA IN MEAT PRODUCTS

Bacteriocins of lactic acid bacteria (LAB) are proteinaceous compounds that may present antimicrobial activity towards important foodborne pathogens and spoilage-related microflora. Due to these properties, bacteriocin-producing strains or purified bacteriocins have a great potential of use in biologically based food preservation systems. Despite the growing number of articles describing the isolation of bacteriocinogenic strains, genetic determinants for production, as well as the purification and biochemical characterization of these inhibitory substances, there are only limited reports of successful application of bacteriocins to meats.

This paper presents a critical review of the methods available for screening of bacteriocin-producing LAB strains from meats and also discusses the proposed mechanisms of action for LAB bacteriocins. Additionally, an overview of the Brazilian experience in the application of LAB bacteriocins to meats and meat products is given.     

FUNDAMENTALS AND PERSPECTIVES FOR THE USE OF BACTERIOCINS PRODUCED BY LACTIC ACID BACTERIA IN MEAT PRODUCTS

Bacteriocins of lactic acid bacteria (LAB) are proteinaceous compounds that may present antimicrobial activity towards important foodborne pathogens and spoilage-related microflora. Due to these properties, bacteriocin-producing strains or purified bacteriocins have a great potential of use in biologically based food preservation systems. Despite the growing number of articles describing the isolation of bacteriocinogenic strains, genetic determinants for production, as well as the purification and biochemical characterization of these inhibitory substances, there are only limited reports of successful application of bacteriocins to meats.

This paper presents a critical review of the methods available for screening of bacteriocin-producing LAB strains from meats and also discusses the proposed mechanisms of action for LAB bacteriocins. Additionally, an overview of the Brazilian experience in the application of LAB bacteriocins to meats and meat products is given.     

Bacteriocins: safe, natural antimicrobials for food preservation.

Bacteriocins are antibacterial proteins produced by bacteria that kill or inhibit the growth of other bacteria. Many lactic acid bacteria (LAB) produce a high diversity of different bacteriocins. Though these bacteriocins are produced by LAB found in numerous fermented and non-fermented foods, nisin is currently the only bacteriocin widely used as a food preservative. Many bacteriocins have been characterized biochemically and genetically, and though there is a basic understanding of their structure-function, biosynthesis, and mode of action, many aspects of these compounds are still unknown. This article gives an overview of bacteriocin applications, and differentiates bacteriocins from antibiotics. A comparison of the synthesis. mode of action, resistance and safety of the two types of molecules is covered. Toxicity data exist for only a few bacteriocins, but research and their long-time intentional use strongly suggest that bacteriocins can be safely used.     

乳酸菌细菌素研究进展及其在水产养殖和加工中的应用

乳酸菌细菌素是一种由乳酸菌在核糖体内合成、具有抑菌活性的多肽或蛋白质。由于乳酸菌通常被认为是安全的微生物,因此由它产生的细菌素受到了广泛地关注。目前由于大部分乳酸菌细菌素抑菌机理研究还不够深入,在一定程度上限制了它的发展和应用。本文对现有乳酸菌细菌素研究成果进行总结,并对细菌素进行了系统分类,阐述了各类乳酸菌细菌素对革兰氏阳性菌的作用机理,最后介绍了乳酸菌细菌素在水产养殖、水产品加工贮藏过程中的应用,旨在为乳酸菌细菌素的应用提供新的探索和基础理论依据。     

Technological characterization of bacteriocin producing Lactococcus lactis strains employed to control Listeria monocytogenes in cottage cheese

In recent years, there has been a particular focus on the application of antimicrobial compounds produced by lactic acid bacteria (LAB) as natural preservatives to control the growth of spoilage and pathogenic bacteria in food. Bacteriocins are antimicrobial peptides which can be added to foods in concentrated forms as food preservatives, e.g. additives, or they can be produced in situ by starters or protective cultures. In this study, twenty Lactococcus lactis bacteriocin producers previously isolated from Italian fermented foods were subjected to a variety of physical and biochemical tests in order to identify those with the greatest potential as starter cultures in cheese production. Of these, four strains isolated from cheese (one nisin Z producer, one nisin A producer and two lacticin 481 producers) which fulfilled the desired technological criteria were assessed for their ability to control Listeria monocytogenes. The subsequent application of these bacteriocinogenic strains as starter cultures in Cottage cheese established that the nisin A producing Lact. lactis 40FEL3, and to a lesser extent the lacticin 481 producers 32FL1 and 32FL3, successfully controlled the growth of the pathogen. This is the first study to directly compare the ability of nisin A, nisin Z and lacticin 481 producing strains to control listerial growth during the manufacture and storage of Cottage cheese.     

细菌素的抑菌机制及其在食品工业中应用进展

由致病菌等微生物污染所引起的食源性疾病和食品腐败变质始终是食品工业面临的巨大难题,而传统的抗生素防腐剂所产生的细菌耐药性会对人体健康造成潜在的威胁。出于人们对于安全和绿色防腐剂的巨大需求,细菌素的研究愈发成为焦点,以期发现可有效控制食源性病原体的新型抗菌物质。细菌素是细菌分泌的多肽或前体多肽,分子量在1~100 ku之间不均匀分布,可以杀死或抑制同一生态系统中竞争营养物质的敏感细菌,少数细菌素还表现出抗病毒和抗真菌等特性。已有研究发现的细菌素具有不同的作用模式,例如：成孔、抑制细胞壁/核酸/蛋白质合成等。该研究综述了细菌素的种类与抑菌作用机制,并结合最新的细菌素在食品工业上的应用,全面概述了细菌素抑菌的特性及其对未来食品行业的应用前景与展望,为细菌素更好的应用在食品工业中提供一定的理论依据,同时对推动食品防腐保鲜技术的革新发展具有重要的意义。     

Exploiting the potential of bacteria in the cheese ecosystem

The diversity of the cheese microbiota contributes greatly to the complexity of the cheese-ripening process, crucially important for developing the unique sensory characteristics of each traditional cheese variety. Interactions between microorganisms, e.g. microbial co-operation and antagonistic effects, markedly impact on the survival, growth and activity of microorganisms in cheese. Bacteriocins are antimicrobials that are produced by lactic acid bacteria (LAB) and enable them to dominate the cheese ecosystem. Recently, there has been interest in the possible use of bacteriocins to promote the lysis of LAB and hence contribute to cheese proteolysis and flavour development. This review examines some of the strategies proposed for controlling bacteria in the cheese ecosystem as a means of ensuring high-quality production standards. It focuses on approaches such as the selection of adjuncts, especially facultatively heterofermentative lactobacilli, the selection of new wild strains of LAB and strategies based on microbial co-operation and microbial antagonism.     

Bacteriocins of lactic acid bacteria: Their potentials as food biopreservative

Abstract

Numerous strains of lactic acid bacteria used in the fermentation of foods are known to produce bacteriocins. In general, bacteriocins are a group of proteinaceous antimicrobial substances that inhibit the growth of closely related bacteria. However, some bacteriocins produced by lactic acid bacteria (LAB) exhibit a relatively broad antimicrobial spectrum and are active against several food‐spoilage and health‐threatening microorganisms. Many investigators have reported on the use of bacteriocins as food preservative to extend the shelflife of various foods. This review decribes the research that has been conducted on bacteriocinogenic lactic acid bacteria— isolated from a wide variety of foods and in some instances of animal origin—and the characteristics of bacteriocins. Special emphasis is placed on their potentials for use as food preservative and on their physicochemical nature, antibacterial spectrum, and genetic behavior.     

Overview of Lactobacillus plantarum as a promising bacteriocin producer among lactic acid bacteria

Chemical preservatives have been traditionally used during the manufacturing of processed products. However, the continuous growing interest of consumers for fresh and natural products makes it necessary to search for alternative compounds. In this context, food industries have been widely using lactic acid bacteria (LAB) as natural preservatives, due to their ability to produce antibacterial compounds such as bacteriocins. Similarly, pharmaceutical industries have improved the use of these bacterial peptides, with antibacterial activity, trying to reduce the indiscriminate use of antibiotics in food products for human and animal consumption. Among LAB, Lactobacillus plantarum can be adapted to various niches thanks to its ability to ferment a wide range of carbohydrates. Additionally, it can be used as starter culture in food fermentations and as an ingredient for probiotic foods, contributing to the organoleptic characteristics of foods at the same time prolonging the shelf-life and safety of these products. The amount of valuable substances obtained from L. plantarum species isolated from different ecological niches is also worth noting, thus proving it to be one of the most important and versatile species among LAB.     

乳酸菌细菌素分类与作用机制

乳酸菌细菌素作为天然的食品防腐剂,可抑制或杀灭食品中致病微生物和腐败微生物从而保护食品的安全。文中介绍了乳酸菌细菌素传统分类方法和新提出的分类方法,并且综述了乳酸菌细菌素的作用机制。     

Production of Bioactive Peptides from Lactic Acid Bacteria: A Sustainable Approach for Healthier Foods

Traditional fermented foods where lactic acid bacteria (LAB) are present have been associated with beneficial effects on human health, and some of those benefits are related to protein‐derived products. Peptides produced by LAB have attracted the interest of food industries because of their diverse applications. These peptides include ribosomally produced (bacteriocins) and protein hydrolysates by‐products (bioactive peptides), which can participate as natural preservatives and nutraceuticals, respectively. It is essential to understand the biochemical pathways and the effect of growth conditions for the production of bioactive peptides and bacteriocins by LAB, in order to suggest strategies for optimization. LAB is an important food‐grade expression system that can be used in the simultaneous production of peptide‐based products for the food, animal, cosmetic, and pharmaceutical industries. This review describes the multifunctional proteinaceous compounds generated by LAB metabolism and discusses a strategy to use a single‐step production process, using an alternative protein‐based media. This strategy will provide economic advantages in fermentation processes and will also provide an environmental alternative to industrial waste valorization. New technologies that can be used to improve production and bioactivity of LAB‐derived peptides are also analyzed.     

安全的天然食品防腐剂细菌素

细菌素是细菌产生的可以杀死或抑制别的细菌生长的抗菌蛋白。许多乳酸菌(LAB)产生各种各样的细菌素，其中的尼生素是唯一的在食品中作为防腐剂广泛使用的细菌素。文章综述了以尼生素为重点对细菌素与抗生素的区别、活性细菌素分子的形成以及其在食品中的应用，并比较了这两种类型的分子的合成、作用模式、抵抗力和安全性。     

The occurrence,growth, and biocontrol of Listeria monocytogenes in fresh and surface-ripened soft and semisoft cheeses

Listeria monocytogenes continues to pose a food safety risk in ready-to-eat foods, including fresh and soft/semisoft cheeses. Despite L. monocytogenes being detected regularly along the cheese production continuum, variations in cheese style and intrinsic/extrinsic factors throughout the production process (e.g., pH, water activity, and temperature) affect the potential for L. monocytogenes survival and growth. As novel preservation strategies against the growth of L. monocytogenes in susceptible cheeses, researchers have investigated the use of various biocontrol strategies, including bacteriocins and bacteriocin-producing cultures, bacteriophages, and competition with native microbiota. Bacteriocins produced by lactic acid bacteria (LAB) are of particular interest to the dairy industry since they are often effective against Gram-positive organisms such as L. monocytogenes, and because many LAB are granted Generally Regarded as Safe (GRAS) status by global food safety authorities. Similarly, bacteriophages are also considered a safe form of biocontrol since they have high specificity for their target bacterium. Both bacteriocins and bacteriophages have shown success in reducing L. monocytogenes populations in cheeses in the short term, but regrowth of surviving cells can commonly occur in the finished cheeses. Competition with native microbiota, not mediated by bacteriocin production, has also shown potential to inhibit the growth of L. monocytogenes in cheeses, but the mechanisms are still unclear. Here, we have reviewed the current knowledge on the growth of L. monocytogenes in fresh and surface-ripened soft and semisoft cheeses, as well as the various methods used for biocontrol of this common foodborne pathogen.     

Heterologous production of bacteriocins by lactic acid bacteria

Over the last two decades, bacteriocins produced by lactic acid bacteria (LAB) have been the subject of considerable research and industrial interest due to their potential as food biopreservatives. The development of heterologous expression systems for such antimicrobial compounds may offer a number of advantages over native systems, such as facilitating the control of bacteriocin gene expression or achieving higher production levels. In addition, the heterologous production by food-grade LAB offers an attractive method for overcoming some of the adverse situations that may affect the effectiveness of some bacteriocins in food systems. Construction of multibacteriocinogenic strains or acquisition of antimicrobial properties by industrial strains are further objectives that can be achieved through the use of heterologous gene expression systems. The development of new biotechnological tools and recent advances in LAB genetics account for the escalating number of studies dealing with heterologous production of bacteriocins by such hosts. This paper reviews the literature published on the subject and compares the different experimental strategies that have been used up to the present for this purpose.     

The importance of lactic acid bacteria for the prevention of bacterial growth and their biogenic amines formation: A review

Foodborne pathogens (FBP) represent an important threat to the consumers' health as they are able to cause different foodborne diseases. In order to eliminate the potential risk of those pathogens, lactic acid bacteria (LAB) have received a great attention in the food biotechnology sector since they play an essential function to prevent bacterial growth and reduce the biogenic amines (BAs) formation. The foodborne illnesses (diarrhea, vomiting, and abdominal pain, etc.) caused by those microbial pathogens is due to various reasons, one of them is related to the decarboxylation of available amino acids that lead to BAs production. The formation of BAs by pathogens in foods can cause the deterioration of their nutritional and sensory qualities. BAs formation can also have toxicological impacts and lead to different types of intoxications. The growth of FBP and their BAs production should be monitored and prevented to avoid such problems. LAB is capable of improving food safety by preventing foods spoilage and extending their shelf-life. LAB are utilized by the food industries to produce fermented products with their antibacterial effects as bio-preservative agents to extent their storage period and preserve their nutritive and gustative characteristics. Besides their contribution to the flavor for fermented foods, LAB secretes various antimicrobial substances including organic acids, hydrogen peroxide, and bacteriocins. Consequently, in this paper, the impact of LAB on the growth of FBP and their BAs formation in food has been reviewed extensively.