Organic Acids and Meat Preservation: A Review

Despite the application of various preservation methods, many problems are still encountered as a result of food spoilage and food poisoning. There is increasing demand for foods produced with milder treatments, and the movement towards more natural and even certified organic foods has been the fastest growing sector of the food industry over the last decade. The interest in bio-preservation of food systems has necessitated the development of new natural antimicrobial compounds from different origins, and in response to modern consumer trends and food legislation, the food industry is faced with serious challenges. Both conventional and organic modes of production are at risk of contamination, but it is possible that organic food might present a bigger problem. Organic acids have been of considerable value as food preservatives since they are also food ingredients and often naturally produced by microorganisms. However, limited data on their effects in commercial practice are available, and despite regulatory approval, organic acids are not widely accepted in commercial practice, and in particular in meat decontamination.

Susceptibility of microorganisms to the most currently used preservatives has been decreasing, and there is concern that decontamination with organic acids could result in the emergence of acid-tolerant food-borne pathogens, evolving to overcome the protective barrier of the human gastric stomach. In the evaluation and integration of new processing/preservation treatments, research objectives would have to include the identification of specific targets of organic acids—understanding the molecular mechanisms that confer high level resistance and analysing pathogen response to antimicrobials. This article provides an overview of various studies done on organic acids as preservatives and highlights aspects such as application, antimicrobial action, and future prospects. Other important issues, such as the application of functional genomics in developing new preservation methods, resistance development, and conventional laboratory procedures are also discussed.     

An insight into curcumin‐based photosensitization as a promising and green food preservation technology

Consumer awareness on the side effects of chemical preservatives has increased the demand for natural preservation technologies. An efficient and sustainable alternative to current conventional preservation techniques should guarantee food safety and retain its quality with minimal side effects. Photosensitization, utilizing light and a natural photosensitizer, has been postulated as a viable and green alternative to the current conventional preservation techniques. The potential of curcumin as a natural photosensitizer is reviewed in this paper as a practical guide to develop a safe and effective decontamination tool for industrial use. The fundamentals of the photosensitization mechanism are discussed, with the main emphasis on the natural photosensitizer, curcumin, and its application to inactivate microorganisms as well as to enhance the shelf life of foods. Photosensitization has shown promising results in inactivating a wide spectrum of microorganisms with no reported microbial resistance due to its particular lethal mode of targeting nucleic acids. Curcumin as a natural photosensitizer has recently been investigated and demonstrated efficacy in decontamination and delaying spoilage. Moreover, studies have shown the beneficial impact of an appropriate encapsulation technique to enhance the cellular uptake of photosensitizers, and therefore, the phototoxicity. Further studies relating to improved delivery of natural photosensitizers with inherent poor solubility should be conducted. Also, detailed studies on various food products are warranted to better understand the impact of encapsulation on curcumin photophysical properties, photo‐driven release mechanism, and nutritional and organoleptic properties of treated foods.     

Eukaryotic Antimicrobial Peptides: Promises and Premises in Food Safety

ABSTRACT:  There is a lack of efficient and safe preservatives in the food industry. Massive use of some common food preservation methods has led, over the years, to development of a resistance to different treatments by various food pathogens. Enteric bacteria are especially tolerant to adverse environmental conditions—such as low pH and high salt concentrations— which limits efficiency of some preservation methods. Consumers demand for natural, preservative-free, and minimally processed foods and worldwide concern regarding disease outbreaks caused by food-related pathogens have created a need for development of new classes of antimicrobial (AM) agents. The twentieth century revealed a massive array of new peptide-based antimicrobials. Small ribosomally made compounds are found in practically all living species where they act as important component of host defense. Certain indubitable advantages of peptides—pertaining to simplicity, activity spectra, and bacterial resistance—over known preservative agents advocate their potential for food preservation. Nisin, an AM compound originating from bacteria, is so far the only FDA-approved peptide. However, a growing number of reports describe the potential of animal-derived antimicrobial peptides as food preservatives. These studies have yielded various native compounds and/or derivatives that possess markedly improved antimicrobial properties under a broad range of incubation conditions. The present work reviews the most investigated peptides and accounts for their potential use as alternatives to the preservatives used today. The focus is on research aspects aiming at understanding the mechanism of action of these peptides at extreme environments of various food systems. Collectively, the data accumulated are convincingly indicative of potential applications of these peptides in food safety, namely, with respect to fighting multidrug-resistant pathogens.     

Bacteriocin-based strategies for food biopreservation

Bacteriocins are ribosomally-synthesized peptides or proteins with antimicrobial activity, produced by different groups of bacteria. Many lactic acid bacteria (LAB) produce bacteriocins with rather broad spectra of inhibition. Several LAB bacteriocins offer potential applications in food preservation, and the use of bacteriocins in the food industry can help to reduce the addition of chemical preservatives as well as the intensity of heat treatments, resulting in foods which are more naturally preserved and richer in organoleptic and nutritional properties. This can be an alternative to satisfy the increasing consumers demands for safe, fresh-tasting, ready-to-eat, minimally-processed foods and also to develop "novel" food products (e.g. less acidic, or with a lower salt content). In addition to the available commercial preparations of nisin and pediocin PA-1/AcH, other bacteriocins (like for example lacticin 3147, enterocin AS-48 or variacin) also offer promising perspectives. Broad-spectrum bacteriocins present potential wider uses, while narrow-spectrum bacteriocins can be used more specifically to selectively inhibit certain high-risk bacteria in foods like Listeria monocytogenes without affecting harmless microbiota. Bacteriocins can be added to foods in the form of concentrated preparations as food preservatives, shelf-life extenders, additives or ingredients, or they can be produced in situ by bacteriocinogenic starters, adjunct or protective cultures. Immobilized bacteriocins can also find application for development of bioactive food packaging. In recent years, application of bacteriocins as part of hurdle technology has gained great attention. Several bacteriocins show additive or synergistic effects when used in combination with other antimicrobial agents, including chemical preservatives, natural phenolic compounds, as well as other antimicrobial proteins. This, as well as the combined use of different bacteriocins may also be an attractive approach to avoid development of resistant strains. The combination of bacteriocins and physical treatments like high pressure processing or pulsed electric fields also offer good opportunities for more effective preservation of foods, providing an additional barrier to more refractile forms like bacterial endospores as well. The effectiveness of bacteriocins is often dictated by environmental factors like pH, temperature, food composition and structure, as well as the food microbiota. Foods must be considered as complex ecosystems in which microbial interactions may have a great influence on the microbial balance and proliferation of beneficial or harmful bacteria. Recent developments in molecular microbial ecology can help to better understand the global effects of bacteriocins in food ecosystems, and the study of bacterial genomes may reveal new sources of bacteriocins.     

Membrane-active bacteriocins to control Salmonella in foods: Are they the definite hurdle?

According to recent surveys salmonellosis is the main disease caused by foodborne microorganisms in many countries. Although traditional methods to control bacterial contamination in food are effective in controlling Salmonella, a major problem arises with fresh and organic food demanded by the market with little preparation and no chemical additives. Besides the development of new technologies that combine soft physical and chemical treatments in a way that causes minimal changes in food properties, antimicrobial peptides derived from natural sources are presented as an interesting alternative to chemical preservatives. There are many bacteriocins active against Salmonella and they could be used in the food industry alone or in combination with other hurdles to increase the anti-Salmonella effect in the so-called hurdle technology. However, further studies are necessary to demonstrate the safety of new bacteriocins and to improve their activity in different environmental conditions encountered during food processing. Moreover, nisin and pediocin PA-1 already approved as food preservatives by various government agencies, can be used along with other hurdles to control the pathogen in foods. In this paper the use of bacteriocins as hurdles for controlling Salmonella in the future is discussed and analyzed.     

植物源精油的抑菌机制及其在食品保鲜包装中的应用进展

随着人们生活水平的不断提高,对饮食结构的要求随之提高,食品安全问题已成为关注焦点之一.而目前在食品生产与包装中使用最广泛的化学防腐剂已不足以满足人们对于安全、健康、绿色的需求.因此,植物源精油的抗菌保鲜方式因其显著的抗菌效果与无毒无残留的特性受到越来越多的关注,其在食品保鲜上的应用已成为研究热点.本文就植物源精油的抑菌...     

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。     

Plant extracts for the control of bacterial growth: efficacy, stability and safety issues for food application

The microbial safety of foods continues to be a major concern to consumers, regulatory agencies and food industries throughout the world. Many food preservation strategies have been used traditionally for the control of microbial spoilage in foods but the contamination of food and spoilage by microorganisms is a problem yet to be controlled adequately. Although synthetic antimicrobials are approved in many countries, the recent trend has been for use of natural preservatives, which necessitates the exploration of alternative sources of safe, effective and acceptable natural preservatives. Plants contain innumerable constituents and are valuable sources of new and biologically active molecules possessing antimicrobial properties. Plants extracts either as standardized extracts or as a source of pure compounds provide unlimited opportunities for control of microbial growth owing to their chemical diversity. Many plant extracts possess antimicrobial activity against a range of bacteria, yeast and molds, but the variations in quality and quantity of their bioactive constituents is the major detriments in their food use. Further, phytochemicals added to foods may be lost by various processing techniques. Several plant extracts or purified compounds intended for food use have been consumed by humans for thousands of years, but typical toxicological information is not available for them. Although international guidelines exist for the safety evaluation of food additives, owing to problems in standardization of plant extracts, typical toxicological values have not been assigned to them. Development of cost effective isolation procedures that yield standardized extracts as well as safety and toxicology evaluation of these antimicrobials requires a deeper investigation.     

Natural antimicrobial/antioxidant agents in meat and poultry products as well as fruits and vegetables: A review

Synthetic preservatives are widely used by the food industry to control the growth of spoilage and pathogenic microorganisms and to inhibit the process of lipid oxidation extending the shelf-life, quality and safety of food products. However, consumer's preference for natural food additives and concern regarding the safety of synthetic preservatives prompted the food industry to look for natural alternatives. Natural antimicrobials, including plant extracts and their essential oils, enzymes, peptides, bacteriocins, bacteriophages, and fermented ingredients have all been shown to have the potential for use as alternatives to chemical antimicrobials. Some spices, herbs and other plant extracts were also reported to be strong antioxidants. The antimicrobial/antioxidant activities of some plant extracts and/or their essential oils are mainly due to the presence of some major bioactive compounds, including phenolic acids, terpenes, aldehydes, and flavonoids. The proposed mechanisms of action of these natural preservatives are reported. An overview of the research done on the direct incorporation of natural preservatives agents into meat and poultry products as well as fruit and vegetables to extend their shelf-life is presented. The development of edible packaging materials containing natural preservatives is growing and their applications in selected food products are also presented in this review.     

Antimicrobial activity of coriander oil and its effectiveness as food preservative

Foodborne illness represents a major economic burden worldwide and a serious public health threat, with around 48 million people affected and 3,000 death each year only in the USA. One of the possible strategies to reduce foodborne infections is the development of effective preservation strategies capable of eradicating microbial contamination of foods. Over the last years, new challenges for the food industry have arisen such as the increase of antimicrobial resistance of foodborne pathogens to common preservatives and consumers demand for naturally based products. In order to overcome this, new approaches using natural or bio-based products as food preservatives need to be investigated. Coriander (Coriandrum sativum L.) is a well-known herb widely used as spice, or in folk medicine, and in the pharmacy and food industries. Coriander seed oil is the world's second most relevant essential oil, exhibiting antimicrobial activity against Gram-positive and Gram-negative bacteria, some yeasts, dermatophytes and filamentous fungi. This review highlights coriander oil antimicrobial activity and possible mechanisms of action in microbial cells and discusses the ability of coriander oil usage as a food preservative, pointing out possible paths for the successful evolution for these strategies towards a successful development of a food preservation strategy using coriander oil.     

植物精油纳米包埋技术的作用机制及其在肉品保鲜中的应用

肉中含有丰富的营养物质且水分活度高,在运输贮藏及销售过程中极易被氧化和腐败变质。因此,肉品保鲜成为食品工业的一大挑战。植物精油作为天然的食品防腐保鲜剂,具有良好的抑菌、抗氧化功效,在肉品保鲜领域具有一定的潜力。但因其水溶性和稳定性较差,限制了在肉品保鲜领域的广泛应用。本文综述了植物精油的抗菌和抗氧化能力及作为肉品保鲜剂所面临的问题、纳米包埋植物精油的方法及对食源性微生物的作用机制。本文通过对纳米包埋植物精油的开发和应用进行展望,为探究新型肉品保鲜剂提供参考。     

抗菌材料在食品包装中的研究进展

食品抗菌包装可以有效抑制被包装食品所处环境中微生物的生长,延长食品的货架期,保证食品品质,在食品领域的地位越发重要。本文阐述了抗菌材料作用机理,介绍了常用的有机抗菌剂、无机抗菌剂和天然抗菌剂,并对食品抗菌包装的5 种实现方式进行了比较。对国内外近年来抗菌材料的研究进展,特别是对天然抗菌剂的应用做了详细说明。最后,结合目前抗菌包装膜和抗菌纸的生产现状,对食品抗菌包装的未来发展趋势和研究重点进行展望。     

Antibiotic-Resistant Bacteria: A Challenge for the Food Industry

Antibiotic-resistant bacteria were first described in the 1940s, but whereas new antibiotics were being discovered at a steady rate, the consequences of this phenomenon were slow to be appreciated. At present, the paucity of new antimicrobials coming into the market has led to the problem of antibiotic resistance fast escalating into a global health crisis. Although the selective pressure exerted by the use of antibiotics (particularly overuse or misuse) has been deemed the major factor in the emergence of bacterial resistance to these antimicrobials, concerns about the role of the food industry have been growing in recent years and have been raised at both national and international levels. The selective pressure exerted by the use of antibiotics (primary production) and biocides (e.g., disinfectants, food and feed preservatives, or decontaminants) is the main driving force behind the selection and spread of antimicrobial resistance throughout the food chain. Genetically modified (GM) crops with antibiotic resistance marker genes, microorganisms added intentionally to the food chain (probiotic or technological) with potentially transferable antimicrobial resistance genes, and food processing technologies used at sub-lethal doses (e.g., alternative non-thermal treatments) are also issues for concern. This paper presents the main trends in antibiotic resistance and antibiotic development in recent decades, as well as their economic and health consequences, current knowledge concerning the generation, dissemination, and mechanisms of antibacterial resistance, progress to date on the possible routes for emergence of resistance throughout the food chain and the role of foods as a vehicle for antibiotic-resistant bacteria. The main approaches to prevention and control of the development, selection, and spread of antibacterial resistance in the food industry are also addressed.     

低聚糖抗菌活性的研究进展

当前我国的食品安全形势仍然非常严峻,寻找安全高效的天然食品贮藏保鲜剂已成为果蔬加工行业的重要研究课题。目前已有很多研究表明低聚糖对植物致病菌和病原微生物的生长具有很好的抑制效果。低聚糖作为食品保鲜剂具有一定的研究意义和应用前景,已经逐渐成为食品行业新的研究热点。本文就目前国内外不同来源的低聚糖抗菌效果和抗菌机理研究进行阐述,重点介绍其在食品保鲜中的研究现状和应用前景。     

噬菌体裂解酶在食品安全领域的研究进展

食源性疾病引发的食品安全问题对人类健康造成严重危害, 其中微生物致病菌是引起食源性疾病的最主要因素,近年来国内外由微生物致病菌引起的食源性疾病事件频频发生,受到世界各国的高度关注。食品工业防治食源性致病微生物的传统方法中,化学防腐剂存在副作用、天然防腐剂较弱的抗微生物活性以及大规模抗生素使用带来的耐药性等一系列问题,使寻求新的抗菌药物或制剂迫在眉睫。噬菌体裂解酶是双链DNA噬菌体复制后期表达, 能够裂解细菌细胞壁释放子代噬菌体的一种蛋白水解酶。随着近些年针对噬菌体及其产物展开的研究不断深入,噬菌体裂解酶凭借高度特异性、不影响正常菌群等特性, 从治疗人类耐药感染到控制多个领域的细菌污染, 成为了包括微生物食品安全在内多种应用中有效的抗微生物制剂。     

Novel approaches for chemical and microbiological shelf life extension of cereal crops

Abstract

Economic losses due to post-harvest fungal spoilage and mycotoxin contamination of cereal crops is a frequently encountered issue. Typically, chemical preservatives are used to reduce the initial microbial load and the environmental conditions during storage are controlled to prevent microbial growth. However, in recent years the consumers’ desire for more naturally produced foods containing less chemical preservatives has grown increasingly stronger. This article reviews the latest advances in terms of novel approaches for chemical decontamination, namely application cold atmospheric pressure plasma and electrolyzed water, and their suitability for preservation of stored cereal crops. In addition, the alternative use of bio-preservatives, such as starter cultures or purified antimicrobial compounds, to prevent the growth of spoilage organisms or remove in-field accumulated mycotoxins is evaluated. All treatments assessed here show potential for inhibition of microbial spoilage. However, each method encounters draw-backs, making industrial application difficult. Even under optimized processing conditions, it is unlikely that one single treatment can reduce the natural microbial load sufficiently. It is evident that future research needs to examine the combined application of several treatments to exploit their synergistic properties. This would enable sufficient reduction in the microbial load and ensure microbiological safety of cereal crops during long-term storage.     

植物精油对病原微生物作用机制及在浆果保鲜上的研究进展

浆果类水果肉质多汁、营养丰富,但采后易于病原微生物生长,从而引起腐败变质,故对浆果中的病原微生物进行抑菌研究是浆果保鲜的关键。植物精油是天然植物体内重要的次生代谢产物,具有广泛的抑菌性能。该文归纳了天然植物精油的来源及主要活性成分,在总结近几年天然植物精油对病原微生物抑菌机制的基础之上,综述了不同精油保鲜方式对浆果类水果进行抑菌保鲜的应用研究进展,并对植物精油应用于浆果保鲜的安全性进行评价。以期为寻求能够替代传统保鲜剂的天然生物资源提供新途径。     

壳聚糖与生物保鲜剂复合使用在水产品保鲜中的研究进展

壳聚糖作为自然界中存在的第二大天然高分子物质,已被广泛应用于食品、医药、环保、工业、化妆品、纺织等领域.在食品加工中,壳聚糖可以抑制水产品中微生物的生长,因此常用于水产品保鲜.但单独使用壳聚糖进行保鲜时,有抗氧化性低、感官品质差等特点,故在实际应用中常加入其他物质进行复合保鲜.生物保鲜剂是从自然界中提取或利用生物工程技...     

Resistance responses of microorganisms in food environments.

Food borne microorganisms display a broad spectrum of resistance responses to naturally occurring and intentionally added antimicrobial agents. Resistance may be conferred by innate structural features of the bacterial strain such as an impermeable outer membrane or a mechanism for antibiotic-inactivation. Bacteria previously susceptible to an antimicrobial compound can acquire resistance through mutation or through genetic transfer processes such as transformation, transduction, and conjugation. Resistance can also be conferred by biofilm formation on food processing surfaces as an adaptive response to protect colonies from cleaning and sanitation. Resistant pathogens are a global problem, facilitated by international trade of raw and processed foods. Cross resistance between clinical and nonclinical antimicrobials can exist and is of concern. The development of resistant foodborne pathogens has been attributed to increased antibiotic use in hospitals, outpatient facilities, and veterinary applications. Resistant microorganisms can also develop as a result of physical processes used in food preservation, such as acid treatments and irradiation processes. Strategies to effectively counter resistance development include: changing current practices of antibiotic usage, developing new antibiotics, applying hurdle preservation approaches, preventing bacterial adhesion, and utilizing competitive exclusion. This paper presents an overview of problems arising from the development of microbial resistance, and explores possible solutions for detecting and defeating the adaptive changes of microorganisms.     

Control of Pathogenic and Spoilage Microorganisms in Fresh‐cut Fruits and Fruit Juices by Traditional and Alternative Natural Antimicrobials

ABSTRACT: Traditional antimicrobials have been extensively used for many years. However, consumers are currently demanding wholesome, fresh‐like, and safe foods without addition of chemically synthesized preservatives. The application of novel natural antimicrobials to assure safety of fresh‐cut fruits and unpasteurized juices while preventing quality loss is a promising alternative. The effectiveness of these natural substances added to fruit derivatives has been studied by different researchers. Antimicrobials of animal (lactoperoxidase, lysozyme, and chitosan), plant (essential oils, aldehydes, esters, herbs, and spices), and microbial origin (nisin) can be used to effectively reduce pathogenic and spoilage microorganisms in fresh‐cut fruits and fruit juices. Nevertheless, the use of these compounds at a commercial level is still limited due to several factors such as impact on sensory attributes or, in some cases, regulatory issues concerning their use. Therefore, extensive research on the effects of each antimicrobial on food sensory characteristics is still needed so that antimicrobial substances of natural origin can be regarded as feasible alternatives to synthetic ones.