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.     

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.     

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.     

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...     

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。     

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。     

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。     

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...     

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.     

Self-preserving cosmetics

Preservatives are added to products for two reasons: first, to prevent microbial spoilage and therefore to prolong the shelf life of the product; second, to protect the consumer from a potential infection. Although chemical preservatives prevent microbial growth, their safety is questioned by a growing segment of consumers. Therefore, there is a considerable interest in the development of preservative-free or self-preserving cosmetics. In these formulations traditional/chemical preservatives have been replaced by other cosmetic ingredients with antimicrobial properties that are not legislated as preservatives according to the Annex VI of the Commission Directive 76/768/EEC and the amending directives (2003/15/EC, 2007/17/EC and 2007/22/EC). 'Hurdle Technology', a technology that has been used for the control of product safety in the food industry since 1970s, has also been applied for the production of self-preserving cosmetics. 'Hurdle Technology' is a term used to describe the intelligent combination of different preservation factors or hurdles to deteriorate the growth of microorganisms. Adherence to current good manufacturing practice, appropriate packaging, careful choice of the form of the emulsion, low water activity and low or high pH values are significant variables for the control of microbial growth in cosmetic formulations. This paper describes the application of the basic principles of 'Hurdle Technology' in the production of self-preserving cosmetics. Multifunctional antimicrobial ingredients and plant-derived essential oils and extracts that are used as alternative or natural preservatives and are not listed in Annex VI of the Cosmetic Directive are also reported.     

天然食品防腐剂及其在食品中的应用研究

食品防腐剂是指为提高食物的色、香、味,或者为延缓由微生物、酶解和氧化引起的食品降解,而添加到食物中的天然物质或化学合成物质。在食品工业中,常用的防腐剂主要为化学合成防腐剂,由于人们食品安全意识的逐步提高,以及化学合成防腐剂对人体健康存在潜在的风险及隐患,消费者对于化学防腐剂的安全性一直存在顾虑。相比之下,天然防腐剂因其抑菌效果好、绿色天然和无毒性的特点越来越受到人们的青睐,消费者对天然防腐剂的需求也日益增加。因而天然防腐剂已然成为当下的研究热点,并且在当今食品行业已得到广泛的研究和应用。文章综述了植物、动物和微生物等不同来源的天然防腐剂及其在食品中的应用,以提高食品质量,延长食品保质期。     

Plant Essential Oils as Active Antimicrobial Agents

Essential oils derived from plants have been recognized for decades to exhibit biological activities, including antioxidant, anticancer, and antimicrobial attributes. Antimicrobial activities of these natural plant materials have been intensively explored in recent years, mainly in response to the overwhelming concern of consumers over the safety of synthetic food additives. Gram-negative organisms are believed to be slightly less sensitive to essential oils than Gram-positive bacteria. Generally, a higher concentration is required to obtain the same efficacy in foods than in synthetic media. The combinations of different types of essential oils or with other food additives have been found to potentially exhibit synergistic if not additive effects. This suggests a cost-efficient and wholesome alternative to both food industry and consumers, at the same time adhering to the hurdle technology in inhibiting proliferation of foodborne pathogens. This review aims to examine the conventional methods commonly used for assessment of antimicrobial activities of essential oils and phytochemicals, the use of these substances as antimicrobials in food products, factors that affect their efficacy, synergism between components or with available food preservatives as well as the challenges and future directions of using essential oils and phytochemicals as natural food preservatives.