抗真菌性乳酸菌生物保护剂的研究进展

霉菌和酵母不仅引起果蔬、谷类、乳制品和肉制品等食品及农产品腐败变质,造成巨大的经济损失,而且霉菌还产生有害于人体健康的黄曲霉毒素、伏马菌素、单端孢霉烯、赭曲霉素A和棒曲霉素等真菌毒素,给食用者带来潜在的食品安全隐患。随着消费者对鲜活和微加工食品的需求不断增加,化学防腐剂在食品中应用受到限制,食品生物保护剂研究及应用已成为热点。乳酸菌通过生态位竞争、形成酸性环境和产生各种代谢产物对致病菌和腐败微生物具有较强的拮抗作用,作为一新型生物保护剂已广泛应用于各种食品中。本文对食品中抗真菌性乳酸菌的筛选和应用、乳酸菌产生的抗真菌代谢产物以及发展趋势进行综述,为进一步探究乳酸菌抗菌机理,研发高效食品生物保护剂提供借鉴与参考。     

乳酸菌抗真菌活性及其抑制真菌毒素的效果

讨论了乳酸菌抗真菌的活性及其清除真菌毒素的3种可能机制，即①乳酸菌通过对霉菌生长的直接抑制，从而抑制真菌毒素的形成；②通过产生代谢产物抑制真菌菌株或降解真菌毒素到无毒或毒性较低的化合物，以此降低真菌毒素的危害；③借助乳酸菌细胞壁与真菌毒素(黄曲霉毒素B1和玉米赤霉烯酮)的物理结合来清除介质中的毒素危害。乳酸菌的抗真菌活性和清除霉菌毒素的能力显然受到菌株、细胞浓度、细胞处理方式和环境条件的影响。新型发酵乳菌株筛选过程中应该考虑乳酸菌菌株的抗真菌活性及其清除真菌毒素的能力。     

乳酸菌对乳制品中黄曲霉毒素的生物防治作用

黄曲霉及其毒素污染常发生于乳制品中,导致一定的经济损失,且严重危害人体健康。乳酸菌及其代谢产物均可有效地吸附去除黄曲霉毒素。就黄曲霉毒素、乳酸菌生物防治作用、乳酸菌对乳制品中黄曲霉毒素生物防治作用的应用及安全性评价进行综述,为提高我国发酵乳制品的卫生安全质量提供理论依据。     

食品中常见霉菌毒素的污染及其检测技术

<正>在自然界中的各种霉菌在自身新陈代谢的过程中会产生次级代谢毒素,会对农作物以及饲料和食品产生不同程度的污染,进而会对人体的健康产生巨大危害。本文研究的重点就是阐述进出口食品中霉菌毒素污染的危害及来源和产生途径,并对这种毒素的检测技术也进行了分析。霉菌及其毒素的产生所谓霉菌,实际上就是丝状真菌的通俗名称,是一种发霉的真菌。这些真菌能够产生纷杂茂盛的菌丝体,但是却和蘑菇这种真菌有着明显区别,没有大     

乳酸菌对制麦和啤酒酿造的影响

利用乳酸菌生物酸化麦芽、糖化醪和麦芽汁酿造的啤酒，有利于啤酒生物稳定性。有些乳酸菌产生乳酸菌素，能抑制某些革兰氏阳性腐败菌的生长。乳酸菌也是霉菌的天然抗菌剂，降低啤酒中霉菌毒素的形成。但大多数乳酸菌是啤酒主要的污染菌，对啤酒质量影响很大。腐败乳酸菌产生生物胺，可以用来检测污染程度。     

核酸适配体生物传感器在食品霉菌毒素检测中应用的研究进展

霉菌毒素是由霉菌产生的次级代谢物,是人类健康的主要威胁之一。食品中霉菌毒素的污染已经成为人们热切关注的主要食品安全问题之一,所以开发出用于简便、快速和灵敏检测食品中霉菌毒素的方法显得尤为重要。核酸适配体是在体外筛选,并能特异性识别目标物的单链寡核苷酸序列,因具有易合成、易标记、易修饰、灵敏度高、特异性高、分子量小等优势而广泛应用于蛋白质、霉菌毒素、农兽药等目标物检测的生物传感器。本文主要综述了食品中霉菌毒素的限量和危害,以及核酸适配体生物传感器筛选技术用于食品中霉菌毒素检测的研究进展。     

失活乳酸菌去除柑橘汁中链格孢霉毒素TeA工艺优化

柑橘果实易受链格孢霉菌等病原微生物的污染产生并积累链格孢霉毒素,其中细交链孢菌酮酸(tenuazonic acid,TeA)是毒性最强的一种链格孢霉毒素,具有潜在的致癌性和细胞毒性,对消费者的健康和安全构成严重威胁。为降低柑橘汁中TeA含量,本研究利用灭活乳酸菌菌体细胞作为吸附剂,主要研究其吸附去除柑橘汁中TeA的工艺条件。首先通过单因素试验分析灭活乳酸菌菌粉添加量、吸附时间、TeA初始质量浓度和pH值对TeA去除率的影响,然后采用响应面法Box-Behnken设计对吸附去除橙汁中TeA工艺条件进行了优化,得到最佳工艺参数为灭活乳酸菌菌粉添加量1.20g/20mL、吸附时间11.43h、TeA初始质量浓度250μg/L、橙汁pH3.15,在此条件下,TeA去除率为86.98%。同时建立了TeA去除率与各影响因素间的二次多项式回归模型,并对该模型进行了验证,结果表明模型拟合程度高,预测效果好。     

酱油中霉菌污染及其检验方法

<正>近年来,各地对食品中霉菌的污染情况陆续有所报导,并发现不少霉菌产生的毒素对人体的肝脏、肾脏、肺脏以及神经、造血、生殖等系统有所损害,特别是某些毒素有强烈的致癌作用,有的可引起霉菌毒素中毒,从而越来越感到对食品中霉菌污染情况的调查的迫切性和重要性。不久前我们对     

现代食品的安全问题——食品污染

食品污染是指食物受到有害物质的侵袭,造成食品安全性、营养性或感官性状发生改变的过程。食品污染大致可分为:(1)食物中存在的天然毒物;(2)环境污染物;(3)滥用食品添加剂;(4)食品加工、贮存、运输及烹调过程中产生的有害物质或工具、用具中的污染物。根据污染物的性质,食品污染可分为三个方面:(1)生物性污染:有微生物及其毒素,主要是细菌及细菌毒素,霉菌及霉菌毒素等;病毒对食品的污染也正引起重视;寄生虫及其虫卵通过病人病畜的粪便或经过环境中转化,最后通过污染食品造成危害;(2)化学性污染:危害最严重的是化学农药、有害金属、多环芳烃…     

食品中的黄曲霉毒素检测措施分析

黄曲霉毒素属于一种真菌类霉菌毒素,黄曲霉毒素主要是黄曲霉和寄生曲霉的次生代谢产物,黄曲霉这一霉菌物质广泛存在于土壤、各类动植物中。在农业种植和生产的过程中,很难避免黄曲霉毒素的产生,并且这类毒素极易留存于花生、大豆、玉米的等粮油农产品中,一旦黄曲霉毒素的量超过了相应的标准,不仅会使食品原料产生剧毒无法进行加工利用,如果被人或者动物误食,将严重威胁其生命安全。那么如何控制食品中的黄曲霉毒素含量就成为了食品检验中的重中之重,这就需要借助一些先进的技术和方法来进行检测,以保证食品的品质和安全。     

Lactic Acid Bacteria as Antifungal and Anti‐Mycotoxigenic Agents: A Comprehensive Review

Fungal contamination of food and animal feed, especially by mycotoxigenic fungi, is not only a global food quality concern for food manufacturers, but it also poses serious health concerns because of the production of a variety of mycotoxins, some of which present considerable food safety challenges. In today's mega‐scale food and feed productions, which involve a number of processing steps and the use of a variety of ingredients, fungal contamination is regarded as unavoidable, even good manufacturing practices are followed. Chemical preservatives, to some extent, are successful in retarding microbial growth and achieving considerably longer shelf‐life. However, the increasing demand for clean label products requires manufacturers to find natural alternatives to replace chemically derived ingredients to guarantee the clean label. Lactic acid bacteria (LAB), with the status generally recognized as safe (GRAS), are apprehended as an apt choice to be used as natural preservatives in food and animal feed to control fungal growth and subsequent mycotoxin production. LAB species produce a vast spectrum of antifungal metabolites to inhibit fungal growth; and also have the capacity to adsorb, degrade, or detoxify fungal mycotoxins including ochratoxins, aflatoxins, and Fusarium toxins. The potential of many LAB species to circumvent spoilage associated with fungi has been exploited in a variety of human food and animal feed stuff. This review provides the most recent updates on the ability of LAB to serve as antifungal and anti‐mycotoxigenic agents. In addition, some recent trends of the use of LAB as biopreservative agents against fungal growth and mycotoxin production are highlighted.     

Detoxification of cancerogenic compounds by lactic acid bacteria strains

ABSTRACT

Carcinogens in food are an important issue that threat people’s health right now. Lactic acid bacteria (LAB) strains as well-known probiotics have shown numerous perspectives in being used as a good food additive to confront cancerogenic compounds in recent years. Some LAB strains can remove cancerogenic compounds from medium environment via direct physical binding and avoid re-pollution of poisonous secondary metabolites which are generated from degradation of cancerogenic compounds. This article presents a whole overview of the physical-binding of LAB strains to such common cancerogenic compounds existed in food and feed environments as mycotoxins, polycyclic aromatic hydrocarbons (PAHs), heterocyclic amines (HAs) and pthalic acid esters (PAEs).In most cases, summaries of these published researches show that the binding of LAB strains to cancerogenic compounds is a physical process. Binding sites generally take place in cell wall, and peptidoglycan from LAB cells is the chief binding site. The adsorption of lactic acid bacteria to cancerogenic compounds is strain-specific. Specially, the strains from the two genera Lactobacillus and Bifidobacterium show a better potential in binding cancerogenic compounds. Moreover, we firstly used molecular dynamic computer model as a highly potential tool to simulate the binding behavior of peptidoglycan from Lactobacillus acidophilus to DBP, one of pthalic acid esters with genetic toxicity. It was seen that the theoretical data were quite consistent with the experimental results in terms of the ability of this bacterium to bind DBP. Also, the toxicity reduction of cancerogenic compounds by LAB strains could be achieved either in gastrointestinal model or animal tests and clinical researches as well. In conclusion, carefully selected LAB strains should be a good solution as one of safety strategies to reduce potential risk of cancerogenic compounds from food-based products.     

酸浆豆腐中产酸菌的耐高温紫外诱变

乳酸菌在食品及食品发酵行业具有广泛的应用,其中以乳酸菌发酵酸浆作为凝固剂的酸浆豆腐已逐渐成为人们关注的热点。酸浆豆腐发酵过程中以乳酸菌为优势菌,在酸浆豆腐点浆时,需在75℃以上高温下进行。普通乳酸菌无法耐受此温度且大量失活,影响产品的后熟。为了开发耐高温乳酸菌,以课题组从云南建水豆腐酸浆中分离的菌株为出发菌,通过紫外诱变的方式,温度梯度筛选获得4株耐高温产酸性能好的菌株。诱变获得4株菌均可在75℃耐高温30 min并保持较好的活性和产酸效果。研究所得突变菌株相比原始菌株均具有更好的耐热性和产酸性。其中HCUL 1.1801-1912Z活性最强、产酸能力最好,为4株菌中最优菌株,将该菌株用于发酵生产酸浆豆腐,将显著提高乳酸菌在豆腐中的活性和豆腐的品质。     

乳酸菌食品级质粒及应用的研究进展

乳酸菌是食品发酵工业中重要的益生菌,利用分子生物学技术构建的菌种对食品产业发展及人类健康具有重要影响。本文主要通过介绍乳酸菌食品级系统的基本要求、食品级质粒的元件组成、食品级质粒构建策略及其应用的研究进展,展示了乳酸菌食品级分子操作系统的建立对乳酸菌的深层次开发利用所具有的重要意义。     

Microbiological and Chemical Changes During the Production of Acidic Whey,A Traditional Chinese Tofu-Coagulant

In this study, acidic whey (AW), a natural tofu-coagulant in China, was investigated for the micro flora and chemical changes of AW during tofu whey natural fermentation. The gel properties of AW tofu coagulated with AW were also studied. Throughout the fermentation stages, the change of lactic acid bacteria (LAB) was found to be similar to that of total mesophilic aerobic bacteria (TMAB), implying that LAB is the most important role that works on AW fermentation. The numbers of enterobacteriaceae, yeast and mould (fungi) were too low to detect. Bacterial spores (spores) and acetibacteria was found to increase slowly with fermentation time. The pH value, protein, carbohydrate, organic acid changes during the production of acidic whey were studied. It was found that the pH value of acidic whey had a significant effect on the gel properties of AW tofu. The microbiological findings in this study have clearly demonstrated the presence of the high counts of LAB investigated and a large amount L-lactic acid produced by LAB must have act as the main tofu coagulant.     

Post-harvest control strategies: minimizing mycotoxins in the food chain

Contamination of cereal commodities by moulds and mycotoxins results in dry matter, quality, and nutritional losses and represents a significant hazard to the food chain. Most grain is harvested, dried and then stored on farm or in silos for medium/long term storage. Cereal quality is influenced by a range of interacting abiotic and biotic factors. In the so-called stored grain ecosystem, factors include grain and contaminant mould respiration, insect pests, rodents and the key environmental factors of temperature, water availability and intergranular gas composition, and preservatives which are added to conserve moist grain for animal feed. Thus knowledge of the key critical control points during harvesting, drying and storage stages in the cereal production chain are essential in developing effective prevention strategies post-harvest. Studies show that very small amounts of dry matter loss due to mould activity can be tolerated. With <0.5% dry matter loss visible moulding, mycotoxin contamination and downgrading of lots can occur. The key mycotoxigenic moulds in partially dried grain are Penicillium verrucosum (ochratoxin) in damp cool climates of Northern Europe, and Aspergillus flavus (aflatoxins), A. ochraceus (ochratoxin) and some Fusarium species (fumonisins, trichothecenes) on temperate and tropical cereals. Studies on the ecology of these species has resulted in modelling of germination, growth and mycotoxin minima and prediction of fungal contamination levels which may lead to mycotoxin contamination above the tolerable legislative limits (e.g. for ochratoxin). The effect of modified atmospheres and fumigation with sulphur dioxide and ammonia have been attempted to try and control mould spoilage in storage. Elevated CO2 of >75% are required to ensure that growth of mycotoxigenic moulds does not occur in partially dried grain. Sometimes, preservatives based on aliphatic acids have been used to prevent spoilage and mycotoxin contamination of stored commodities, especially feed. These are predominantly fungistats and attempts have been made to use alternatives such as essential oils and anti-oxidants to prevent growth and mycotoxin accumulation in partially dried grain. Interactions between spoilage and mycotoxigenic fungi and insect pests inevitably occurs in stored grain ecosystems and this can further influence contamination with mycotoxins. Effective post-harvest management of stored commodities requires clear monitoring criteria and effective implementation in relation to abiotic and biotic factors, hygiene and monitoring to ensure that mycotoxin contamination is minimised and that stored grain can proceed through the food chain for processing.     

乳酸菌食品级表达系统的研究进展

乳酸菌是一类广泛使用的工业菌.近几十年来,乳酸菌作为同源和异源蛋白表达的宿主菌的潜在应用已得到深入研究,在此基础上建立和发展了乳酸菌食品级基因表达系统.首先介绍了乳酸菌食品级表达系统的一些基本条件,表达和标记系统的适用原则,然后追踪其前沿应用进展情况,对乳酸菌食品级基因表达系统的最新应用进行了归纳,根据此表达系统在当前食品经济中的位置,对其在食品工业、医药和保健品等领域的应用前景进行了展望.     

乳酸菌耐盐分子机制研究进展

乳酸菌广泛应用于食品和发酵行业。在酱油、熏肉、泡菜等发酵食品的生产过程中,乳酸菌的生长常受到 高盐浓度的影响。盐胁迫引起的渗透压变化会引起乳酸菌细胞结构损伤,导致细胞生理代谢活动紊乱甚至死亡。因 此,乳酸菌在盐胁迫条件下生存、生长和代谢的能力在食品发酵过程中是非常重要的。本文就乳酸菌的耐盐机制进 行阐释,以期为乳酸菌科学研究及食品发酵工业应用提供参考。     

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。     

Probiotic potential of lactic acid bacteria from fermented Malaysian food or milk products

This study investigated the probiotic characteristics of lactic acid bacteria (LAB) isolated from 14 Malaysian fermented food or milk products. In total, 22.3% (121 of 542) of the LAB isolated from the local fermented products exhibited antibacterial activity against Micrococcus luteus. Twelve LAB that demonstrated better antibacterial activity against M. luteus as compared to a commercial strain Lactobacillus casei strain Shirota (LABPC) were selected for further characterisation. Based on 16S rRNA gene sequence, the LAB were identified as pediococci (seven) and lactobacilli (five). All 12 LAB showed bile tolerance, but only eight were acid tolerant at pH ≥ 3.0. The highest level of adhesion to HT‐29 cells was observed among the Lactobacillus sp. LAB 1 and 10. The LAB also showed antimicrobial activity against Escherichia coli and Staphylococcus aureus through the production of organic acids. LAB isolated from Malaysian fermented food and milk products, especially fermented tapioca, contains potential probiotic candidates.