Nisin as a Food Preservative: Part 2: Antimicrobial Polymer Materials Containing Nisin

Nisin is the only bacteriocin approved as a food preservative because of its antibacterial effectiveness and its negligible toxicity for humans. Typical problems encountered when nisin is directly added to foods are mainly fat adsorption leading to activity loss, heterogeneous distribution in the food matrix, inactivation by proteolytic enzymes, and emergence of resistance in normally sensitive bacteria strains. To overcome these problems, nisin can be immobilized in solid matrices that must act as diffusional barriers and allow controlling its release rate. This strategy allows maintaining a just sufficient nisin concentration at the food surface. The design of such antimicrobial materials must consider both bacterial growth kinetics but also nisin release kinetics. In this review, nisin incorporation in polymer-based materials will be discussed and special emphasis will be on the applications and properties of antimicrobial food packaging containing this bacteriocin.     

水蕨提取物的抗菌作用及其应用研究

为了探讨可食野生植物水蕨的消炎防腐性能,利用了水蕨植株和孢子的水溶性及醇溶性粗提取物作抑菌和食品保鲜实验。结果表明：两组提取物对革兰氏阳性和阴性细菌的生长都有一定的抑制作用,而对真菌无明显抑制现象;食品保鲜试验显示: 水蕨植株的水提取物和孢子的乙醇提取物能延长肉类熟食和新鲜海鲜的一级保鲜期12h以上,而水蕨植株的乙醇提取物和孢子的水提取物效果一般,说明水蕨植株中的抗菌成分与孢子中的成分可能有所区别。     

抗菌肽及其在食物储藏与保鲜中的应用

抗菌肽是抵抗外源病原微生物的天然免疫小分子多肽,存在于多种生物体内,具有广谱抗菌、可抑制多重耐药菌的繁殖、活性稳定、免疫原性低、绿色无公害等优点,在食物储藏与保鲜中显示了巨大的应用潜力.对抗菌肽的功能、制备方法、抗菌机制及其在食品储藏和保鲜中的应用进行了总结分析,以期为发展有针对性的新型食物保鲜剂提供思路.     

甲壳低聚糖抗菌作用及其在食品保藏中的应用

报道了甲壳低聚糖对食品中一些常见的细菌、霉菌、酵母菌的抗菌作用，其抑菌率明显超过对照组，相应最小抑菌质量浓度为１～１０ｇ／Ｌ，随着甲壳低聚糖质量浓度增加，抑菌作用逐渐变强。并探讨了甲壳低聚糖抗菌活性与结构之间的关系，结果表明甲壳低聚糖的抗菌活性与氨基含量和氨基质子化以及相对分子质量大小有关。此外，当甲壳低聚糖作为防腐剂应用于苹果原汁保藏时，在果汁中含４ｇ／Ｌ甲壳低聚糖可使果汁的保藏期由对照实验中３７℃时９ｄ增加到７０ｄ，显示了很好的防腐效果。     

新型防腐剂富马酸纤维二糖甲酯的合成及抗菌特性研究

茂名学院化学与生命科学学院(茂名525000)摘要基于食品防腐防霉剂的结构-活性关系研究结果,合成了具有α,β-不饱和羰基功能基团的新型食品防腐剂——富马酸纤维二糖甲酯。抑菌活性试验结果表明:富马酸纤维二糖甲酯对牛奶酸败混合菌的生长具有良好的抑菌能力,抑菌效果优于富马酸单甲酯,接近苯甲酸。     

新型防腐剂富马酸半乳糖甲酯的合成及抗菌特性研究

基于食品防腐防霉剂的结构-活性关系研究结果,以马来酸酐和甲醇为原料,经酯化及异构化得到富马酸单甲酯,再经酰氯化得到富马酸单甲酯单酰氯。富马酸单甲酯单酰氯与半乳糖反应,在相转移催化剂四丁基溴化铵的作用下,得到具有α、β-不饱和羰基结构的富马酸半乳糖甲酯。抑菌活性试验结果表明:富马酸半乳糖甲酯对混合菌具有良好的抑菌能力,抑菌效果优于富马酸单甲酯,接近苯甲酸。     

Antimicrobial Coatings for Food Contact Surfaces: Legal Framework,Mechanical Properties,and Potential Applications

Food contact surfaces (FCS) in food processing facilities may become contaminated with a number of unwanted microorganisms, such as Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus. To reduce contamination and the spread of disease, these surfaces may be treated with sanitizers or have active antimicrobial components adhered to them. Although significant efforts have been devoted to the development of coatings that improve the antimicrobial effectiveness of FCS, other important coating considerations, such as hardness, adhesion to a substrate, and migration of the antimicrobial substance into the food matrix, have largely been disregarded to the detriment of their translation into practical application. To address this gap, this review examines the mechanical properties of antimicrobial coatings (AMC) applied to FCS and their interplay with their antimicrobial properties within the framework of relevant regulatory constraints that would apply if these were used in real‐world applications. This review also explores the various assessment techniques for examining these properties, the effects of the deposition methods on coating properties, and the potential applications of such coatings for FCS. Overall, this review attempts to provide a holistic perspective. Evaluation of the current literature urges a compromise between antimicrobial effectiveness and mechanical stability in order to adhere to various regulatory frameworks as the next step toward improving the industrial feasibility of AMC for FCS applications.     

抗菌肽应用于食品中的研究现状及面临的挑战

食品安全问题一直为人们所关注,其中微生物污染是导致食品腐败变质的主要原因。抗菌肽来源广泛,抑菌谱广,杀菌速度快,可以较好地控制食品中腐败微生物的滋生;对pH值、蛋白酶和热处理有较好的稳定性,在成分复杂的食品体系中有一定的适用性;由于其抑菌机理特殊,不易产生耐药性;部分具有抗氧化和提高免疫力等多种功能,对人体具有一定的保健作用。抗菌肽的以上特点满足了人们对新型防腐保鲜剂的多种需求,有望在食品工业上发挥重大作用。因此,在抗菌肽的生物学功能以及抗菌肽保鲜机理简单介绍的基础上,对抗菌肽应用于不同食品中的研究现况进行详细综述,最后对抗菌肽在食品中应用目前存在的问题和发展方向提供了思考。     

Enhancing Physical Properties and Antimicrobial Activity of Konjac Glucomannan Edible Films by Incorporating Chitosan and Nisin

ABSTRACT: The antimicrobial effect of konjac glucomannan (KGM) edible ûlm incorporating chitosan (CHI) and nisin at various ratios or concentrations was studied. This activity was tested against pathogenic bacteria, namely, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes , and Bacillus cereus. Mechanical and physical properties were determined, and the results indicated that the blend film KC2 (mixing ratio KGM 80/ CHI 20) showed the maximum tensile strength (102.8 ± 3.8 MPa) and good transparency, water solubility, and water vapor transmission ratio. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the structural change of the blend films; and the results showed that strong intermolecular hydrogen bonds occurred between CHI and KGM. Incorporation of nisin at 463IU per disk of film for the selected KC2 was found to have antimicrobial activity against S. aureus, L. monocytogenes , and B. cereus. The mean value of inhibition zone diameter of the CHI-N series and the KC2-N series were higher than the KGM-N series at each corresponding concentration and with significant difference ( P < 0.05), however, there was no significant difference in the antimicrobial effect between CHI and KC2 incorporating nisin. At all these levels, the blend ûlm KC2-nisin had a satisfactory appearance, mechanical and physical properties, and antimicrobial activity. Therefore, it could be considered as a potential "active" packaging material.     

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.     

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。     

Essential Oils: Extraction,Bioactivities, and Their Uses for Food Preservation

Essential oils are concentrated liquids of complex mixtures of volatile compounds and can be extracted from several plant organs. Essential oils are a good source of several bioactive compounds, which possess antioxidative and antimicrobial properties. In addition, some essential oils have been used as medicine. Furthermore, the uses of essential oils have received increasing attention as the natural additives for the shelf‐life extension of food products, due to the risk in using synthetic preservatives. Essential oils can be incorporated into packaging, in which they can provide multifunctions termed “active or smart packaging.” Those essential oils are able to modify the matrix of packaging materials, thereby rendering the improved properties. This review covers up‐to‐date literatures on essential oils including sources, chemical composition, extraction methods, bioactivities, and their applications, particularly with the emphasis on preservation and the shelf‐life extension of food products.     

Antimicrobial Activity of Ginger (Zingiber Officinale) and Its Application in Food Products

Ginger (Zingiber officinale) is a plant used in traditional medicine against different diseases because of its various properties (antimicrobial, antioxidant, anti-inflammatory, anticoagulant, etc.). Ginger is “generally recognized as safe” by the Food and Drug Administration. Numerous studies have been carried out to characterize and isolate its main bioactive compounds to elucidate the mechanisms of its antimicrobial activity against pathogenic and spoilage microorganisms in foods. Results indicate that ginger contains monoterpenoids, sesquiterpenoids, phenolic compounds, and its derivatives, aldehydes, ketones, alcohols, esters, which provide a broad antimicrobial spectrum against different microorganisms and make it an interesting alternative to synthetic antimicrobials. However, its application in foods has been scarcely explored and represents an opportunity area for further research. This review provides an updated overview of the main bioactive compounds of ginger, its potential application, and toxicity as an antimicrobial in food products.     

活性包装薄膜的功能特性表征及对食品保鲜作用的研究进展

本文综述了活性包装薄膜的功能特性表征与对食品保鲜作用的研究进展,归纳总结了薄膜抗菌和抗氧化功能的表征方法,并从这两个方面介绍了薄膜对食品的保鲜作用,旨在为今后的研究提供参考。活性包装薄膜抗菌功能的表征方法主要有抑菌圈法、抑菌率法、微生物生长曲线法和包装食品直接测定法等,抗氧化功能的表征方法主要有自由基清除法、铁离子还原/抗氧化能力法和包装食品直接测定法等。薄膜对食品的保鲜作用主要体现在薄膜对所包装食品中微生物生长的抑制,对脂类、蛋白质氧化进程的减缓以及食品货架期的延长。     

海洋鱼源抗菌肽的研究进展及其在食品安全中的应用前景

抗生素过度使用所导致日益严重的耐药性威胁已成为制约食品工业可持续发展的障碍,而海洋鱼类中存在具有广谱抗微生物活性的抗菌肽,其或将成为最佳的新型抗生素替代物.因此,从海洋鱼类中发现更多活性丰富的抗菌肽,并探索其在食品安全领域应用的相关研究成为热点.本文综述了海洋鱼源抗菌肽的结构、生物活性及作用机制的研究进展,并展望了...     

Structure,Physicochemical Properties,Modifications, and Uses of Sorghum Starch

Sorghum has great drought resistance and can be cultivated on marginal lands with minimal input costs. Thus, the supply of sorghum starch, the major component of the seeds, can be cheap and sustainable. This review summarizes the present knowledge of extraction, composition, granular and molecular structures, physicochemical properties, modifications, and uses of sorghum starch, and provides suggestions for needed research to improve our understanding and utilization of this starch.     

壳聚糖对于肉类食品防腐和保鲜的应用研究进展

壳聚糖是1种来源于蟹、虾等甲壳类动物贝壳的天然高分子聚合物.对于多种食源性丝状真菌、酵母、细菌等具有广谱抗性,并且具有很好的抗脂质过氧化作用.以壳聚糖为材料制成的包装膜,具有透气屏障的作用,可以延缓被包裹物与外界的气体交换以及包裹物自身营养成分的流失.这些特性使壳聚糖作为潜在的食品防腐剂或食品包裹材料具有很高的市场应用潜力和应用价值.本文主要对近年来壳聚糖作为食品防腐剂在延长生鲜肉、鱼、火腿制品保存期方面的研究和应用情况进行了综述.     

氧化淀粉的抑菌效果及草莓涂膜保鲜应用

本实验采用抑菌圈法研究氧化淀粉（oxidized starch,OST）的抑菌作用,通过测定草莓的质量损失率、腐烂率、菌落总数等理化指标研究OST对草莓的保鲜效果。结果表明：OST对常见致病菌金黄色葡萄球菌、大肠杆菌和常见草莓腐败菌青霉菌均具有明显的抑菌效果,OST中羧基相对含量越高则抑菌能力越强,其中羧基相对含量达57%的OST（OST-57）对金黄色葡萄球菌、大肠杆菌和青霉菌形成的抑菌圈直径分别为（29.00±0.87）、（28.00±1.73）、（15.75±0.65）mm;与未经处理草莓相比,OST-57对草莓的涂膜处理能够有效抑制菌落总数增长,显著降低草莓质量损失率和腐烂率（P＜0.05）,延缓草莓成熟过程中硬度和咀嚼性的变化,同时能够显著维持可溶性固形物和花色苷等营养物质含量（P＜0.05）。结论：OST-57浸泡涂膜处理能够更有效地延缓草莓果实的成熟衰老,可作为新型的果蔬涂膜材料,对于果蔬的采后保鲜具有应用价值。     

Using Photocatalyst Metal Oxides as Antimicrobial Surface Coatings to Ensure Food Safety—Opportunities and Challenges

Cross‐contamination of foods with pathogenic microorganisms such as bacteria, viruses, and parasites may occur at any point in the farm to fork continuum. Food contact and nonfood contact surfaces are the most frequent source of microbial cross‐contamination. In the wake of new and emerging food safety challenges, including antibiotic‐resistant human pathogens, conventional sanitation and disinfection practices may not be sufficient to ensure safe food processing, proper preparation, and also not be environmentally friendly. Nanotechnology‐enabled novel food safety interventions have a great potential to mitigate the risk of microbial cross‐contamination in the food chain. Especially engineered nanoparticles (ENPs) are increasingly finding novel applications as antimicrobial agents. Among various ENPs, photocatalyst metal oxides have shown great promise as effective nontargeted disinfectants over a wide range of microorganisms. The present review provides an overview of antimicrobial properties of various photocatalyst metal oxides and their potential applications as surface coatings. Further, this review discusses the most common approaches to developing antimicrobial coatings, methods to characterize, test, and evaluate antimicrobial efficacy as well as the physical stability of the coatings. Finally, regulations and challenges concerning the use of these novel photocatalytic antimicrobial coatings are also discussed.