乳酸菌抗真菌生物防腐剂作用机理和前景展望

食品在储藏过程中易受霉菌及其产生的毒素的污染,严重危害人类健康。许多研究发现有些乳酸菌能够通过产生的有机酸、短肽、过氧化氢、以及其自身的吸附能力等抑制霉菌生长,吸附真菌毒素,以降低食品中霉菌及其毒素的含量,延长食品货架期。对乳酸菌的代谢产物及其抗真菌活性的深入研究表明,乳酸菌作为生物防腐剂具有良好的应用前景,有望成为安全的食品添加剂。     

真菌毒素免疫检测技术的研究进展

<正>真菌毒素的特性及起源真菌毒素,又称霉菌毒素,是指霉菌在其所污染食品中产生的有毒代谢产物,可通过进食进入人或动物体内,引起人或动物的急性或慢性中毒,进而损害机体的肝脏、肾脏、神经组织等。致癌性是真菌毒素对机体最严重和最普遍的危害。真菌毒素可在农作物生长或收获时形成,也会因贮存条件的不适宜而产生。湿度或温度高的环境通常有利于粮食和饲料中霉菌的生长及其毒素的产生。真菌毒素最早于1960年被     

乳酸菌协同小麦胚芽油发酵对黑曲霉生长活性的影响

本文通过初筛和复筛考察不同乳酸菌的抗真菌活性,并将小麦胚芽油添加入乳酸菌培养液中进行发酵,旨在明确乳酸菌协同小麦胚芽油发酵对抗黑曲霉活性的影响。研究表明,小麦胚芽油不具有抑制黑曲霉生长的能力,而乳杆菌LF5发酵液抑菌率随着小麦胚芽油浓度的升高明显提升,且该现象具有菌株特异性。通过加热、中和pH、添加蛋白酶及过氧化氢酶发现,乳酸菌协同发酵上清液中的抗真菌活性物质主要由有机酸以及部分具有良好热稳定性的非蛋白类组分组成。此外,采用乳杆菌LF5协同小麦胚芽油发酵制备面包,在第5 d发现肉眼可见霉菌,与空白组(第2~3 d)相较具有显著抑制黑曲霉生长活性的作用,为乳酸菌在发酵米面食品中的应用提供了新的方向。     

农产品中真菌毒素的微生物脱除研究进展

农产品中的真菌毒素污染,不仅造成农业产业的巨大经济损失,而且直接危害人类的身体健康。虽然物理法与化学法在早期真菌毒素脱除中发挥了一定的作用,但是通过微生物脱除真菌毒素,作为一种安全、高效、经济的方式越来越受到认可。本文综述微生物对农产品中常见真菌毒素的两种主要脱除方式（吸附和降解）,前者主要包括乳酸菌及酵母,以菌体吸附的方式,对黄曲霉毒素、玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、赭曲霉毒素、T2毒素、伏马毒素B1、展青霉素等真菌毒素的脱除效果较好;后者则集中体现在红球菌、芽孢杆菌、假单胞菌及酵母,依靠微生物代谢的方式对上述毒素进行降解。通过对研究报道的归纳和总结,概述了常见的真菌毒素脱除菌株及其代谢机制的研究进展,以及其在农产品真菌毒素脱毒方面的创新性变革。     

真菌毒素与食品酿造工业

论述了真菌毒素的种类、产生的原因和毒素的理化性质；真菌毒素的危害；黄曲霉毒素的产生和鉴别；食品酿造工业中黄曲霉毒素的防治等一系列问题。特别是对黄曲霉毒素的产生原因和产霉菌株的鉴别及在食品酿造工业中的防治做了深入的介绍。     

纳他霉素——一种抗真菌生物防腐剂

纳他霉素是26种多烯大环内酯类抗真菌抗生素的一种，主要由3种链霉菌产生，分别是恰努加链霉菌（Streptomyces chattanovgensis）、纳塔尔链霉菌（Streptomyces natalensis）和褐黄孢链霉菌（Streptomyces gilvosporeus），经发酵、提取、精制获得的具有广谱、双效的生物防腐剂。它既可以抑制各种霉菌、酵母的生长引起的食品腐败，又能抑制真菌毒素的产生，防止造成毒素型食物中毒。     

乳酸菌在制麦和酿造中的使用对抗真菌毒素和喷涌之间的关系

乳酸菌（LAB）的代谢特性对麦芽和啤酒质量、安全性和改善风味方面有特殊的影响。本文回顾了LAB在制麦和酿造中的应用，讨论了谷物中真菌毒素的产生并回顾了它们对啤酒的影响。主要从以下几方面阐述：制麦和酿造中的LAB起子培养物；乳酸麦芽的制备；酿造过程中糖化醪和麦汁的生物酸化；酿造过程中LAB所产生的细菌素；LAB及其抗真菌活性；谷物中的真菌毒素。     

不同乳酸菌菌株抗氧化能力的比较研究

目的：比较不同乳酸菌菌株的抗氧化能力,为其天然抗氧化剂的开发提供理论依据。方法：通过羟自由基清除实验,超氧阴离子自由基清除实验,DPPH 自由基清除实验以及还原能力测定实验,对35 株乳酸菌的菌体、无细胞提取物以及胞外分泌物的抗氧化能力进行研究。结果：比较发现La 5 和La 29 两株乳酸菌抗氧化能力相对较高。结论：不同来源的乳酸菌菌株还原能力不同,且在羟自由基、超氧阴离子自由基和DPPH 自由基的清除能力方面存在差异;且其发挥抗氧化作用的活性物质存在的部位也因菌株的不同而具有较大的差异性。     

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。     

新疆熏马肠中具有较高抗氧化活性乳酸菌的筛选鉴定

通过对从熏马肠中分离出的6株乳酸菌的完整细胞和无细胞提取物进行清除DPPH自由基、羟自由基、超氧阴离子,螯合铁离子,还原能力,抗脂质过氧化等抗氧化活性测定实验来获得具有较高抗氧化活性的乳酸菌。结果表明:6株乳酸菌的抗氧化能力存在差异,完整细胞的抗氧化活性显著高于无细胞提取物(P0.05),其中X_(31)的清除DPPH自由基、超氧阴离子,螯合铁离子,抗脂质过氧化能力显著高于其他菌株(P0.05);X_(11)的清除羟自由基、还原能力显著高于其他菌株(P0.05),综合比较X_(31)和X_(11)具有较高抗氧化活性。再利用生理生化实验和16S rDNA序列比对的方法对其进行鉴定,表明X_(31)、X_(11)均为戊糖片球菌。     

QuEChERS-高效液相色谱-质谱法检测食品中14 种真菌毒素

建立QuEChERS-高效液相色谱-质谱检测食品中14 种真菌毒素的方法。均质样品用1%乙酸-乙腈提取,经分散固相萃取净化后,采用ACQUITU UPLC BEH C18色谱柱（2.1 mm×50 mm,1.7 μm）分离。采用电喷雾电离、多反应监测方式,可同时对食品中脱氧雪腐镰刀菌烯醇、青霉酸、黄曲霉毒素M1、黄曲霉毒素G2、桔青霉毒素、黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、玉米赤霉烯酮、赭曲霉毒素A、杂色曲霉毒素、HT-2毒素、T-2毒素、鬼臼毒素14 种真菌毒素进行定性和定量分析。最低检出限为0.5～1 μg/kg。该方法简便快速、选择性佳、灵敏度高,适用于食品安全事件分析中真菌毒素的分析。     

Reduction of fumonisin B1 and zearalenone by lactic acid bacteria in fermented maize meal

Fusarium species are fungi that infect maize products worldwide and elaborate mycotoxins, which have been associated with cancer. This study was carried out to investigate the potential of lactic acid bacteria fermentation in reducing mycotoxin concentration and toxicity in maize meal products. Maize meal was spiked separately with fumonisin B1 and zearalenone and then allowed to ferment for 4 days. The potential cytotoxicity of the mycotoxin-spiked fermented extracts was also investigated using the SNO human esophageal carcinoma cell line (the SNO cell line was explanted from a cancer patient, S.N., a 62-year-old Zulu man, in July 1972). A significant decrease (P < 0.05) in the concentration of the two mycotoxins was observed, with a 56 to 67% and a 68 to 75% reduction in the third and fourth days, respectively. The two mycotoxins were not detectable in commercially fermented maize meal (amahewu) samples. After fermentation, mycotoxin-spiked maize meal samples containing lactic acid bacteria culture were comparatively less toxic to SNO cells than were samples without lactic acid bacteria. However, this difference in toxicity was not significant (P > 0.05). These results indicate that lactic acid bacteria fermentation can significantly reduce the concentration of mycotoxins in maize. However, such a reduction may not significantly alter the possible toxic effects of such toxins. The exact mechanism of toxin reduction warrants further investigation.     

Strategies to prevent mycotoxin contamination of food and animal feed: a review

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to vertebrates produced by many important phytopathogenic and food spoilage fungi including Aspergillus, Penicillium, Fusarium, and Alternaria species. The contamination of foods and animal feeds with mycotoxins is a worldwide problem. We reviewed various control strategies to prevent the growth of mycotoxigenic fungi as well as to inhibit mycotoxin biosynthesis including pre-harvest (resistance varieties, field management and the use of biological and chemical agents), harvest management, and post-harvest (improving of drying and storage conditions, the use of natural and chemical agents, and irradiation) applications. While much work in this area has been performed on the most economically important mycotoxins, aflatoxin B(1) and ochratoxin A much less information is available on other mycotoxins such as trichothecenes, fumonisin B(1), zearalenone, citrinin, and patulin. In addition, physical, chemical, and biological detoxification methods used to prevent exposure to the toxic and carcinogenic effect of mycotoxins are discussed. Finally, dietary strategies, which are one of the most recent approaches to counteract the mycotoxin problem with special emphasis on in vivo and in vitro efficacy of several of binding agents (activated carbons, hydrated sodium calcium aluminosilicate, bentonite, zeolites, and lactic acid bacteria) have also been reviewed.     

Mycotoxin production in wheat grains by different Aspergilli in relation to different relative humidities and storage periods

Four different Aspergilli (Aspergillus oryzae, A. parasiticus, A. terreus and A. versicolor) were grown on wheat grains underdifferent degrees of relative humidity 14, 50, 74, 80 and 90%. Samples of wheat grains were taken monthly for a period of six months and examined for mycotoxin production. A. oryzae was found to produce aflatoxins B1, B2, zearalenone, DON and T-2 toxins under elevated degrees of humidity and prolonged periods of storage. A. parasiticus produced aflatoxins B1, G1, NIV, DON and T-2 toxins in high concentrations during a period of not more than three months storage at 14% relative humidity; at an increased level of relative humidity of 74% ochratoxin A, zearalenone and sterigmatocystin were also produced at high levels. The isolate was drastic in toxin production. A. terrus produced toxins at 14% relative humidity (aflatoxin G2 and DON) at levels much higher than any other prevalent degrees of humidity. A. versicolor is highly sensitive to relative humidity and grain moisture content It produced aflatoxins B1, G1, NIV and DON at a relative humidity of 50% and another toxins (aflatoxin G2, ochratoxins A, B and zearalenone) at 74%. The microorganism can be considered a trichothecene producer under suitable relative humidity.     

Mycotoxins in corn and wheat silage in Israel

Silage is an important feed source for intensive dairy herds worldwide. Fungal growth and mycotoxin production before and during silage storage is a well-known phenomenon, resulting in reduced nutritional value and a possible risk factor for animal health. With this in mind, a survey was conducted to determine for the first time the occurrence of mycotoxins in corn and wheat silage in Israel. A total of 30 corn and wheat silage samples were collected from many sources and analysed using a multi-mycotoxin method based on LC-MS/MS. Most mycotoxins recorded in the present study have not been reported before in Israel. Overall, 23 mycotoxins were found in corn silage; while wheat silage showed a similar pattern of mycotoxin occurrence comprising 20 mycotoxins. The most common post-harvest mycotoxins produced by the Penicillium roqueforti complex were not found in any tested samples, indicative of high-quality preparation and use of silage. Moreover, none of the European Union-regulated mycotoxins – aflatoxin B1, ochratoxin, T-2 toxin, diacetoxyscirpenol and deoxynivalenol – were found above their limits of detection (LODs). The Alternaria mycotoxins – macrosporin, tentoxin and alternariol methyl ether – were highly prevalent in both corn and wheat silage (>80%), but at low concentrations. The most prominent (>80%) Fusarium mycotoxins in corn silage were fusaric acid, fumonisins, beauvericin, monilifomin, equisetin, zearalenone and enniatins, whereas in wheat silage only beauvericin, zearalenone and enniatins occurred in more than 80% of the samples. The high prevalence and concentration of fusaric acid (mean = 765 µg kg^–1) in Israeli corn silage indicates that this may be the toxin of highest potential concern to dairy cow performance. However, more data from different harvest years and seasons are needed in order to establish a more precise evaluation of the mycotoxin burden in Israeli silage.     

Carcinogenic and genotoxic effects of mycotoxins

Aflatoxin B1 is the most potent hepatocarcinogen among the naturally occurring compounds. It's carcinogenic effect was confirmed by longterm-studies in several animal species. There exists detailed knowledge on the molecular mechanism of the carcinogenic effect caused by aflatoxin B1. At present there does not exist a reliable evidence that human primary hepatocellular carcinoma is caused by aflatoxins. Sterigmatocystin is a hepatocarcinogen too. The genotoxicity of sterigmatocystin likewise as of aflatoxin B1 was detected by short-term-tests with microbial systems and mammalian cells in vitro. It is disputable whether ochratoxin A, citrinin and T-2 toxin are carcinogenic or not. Diacetoxyscirpenol, zearalenone and patulin are estimated as not carcinogenic after longterm-studies with oral toxin administration. Patulin and penicillic acid are genotoxic in microbial systems respectively in mammalian cells in vitro. Luteoskyrin is carcinogenic, but there was not detected any genotoxicity.     

Binding of zearalenone, aflatoxin B1, and ochratoxin A by yeast-based products: a method for quantification of adsorption performance

A methodology was developed to quantify the efficiency of yeast-based products for adsorption of three mycotoxins: zearalenone (ZEA), aflatoxin B(1) (AFB(1)), and ochratoxin A (OTA). Eight products were tested (yeast cell wall or inactivated yeast). The described experimental protocol based on in vitro tests provided reliable isotherms for each mycotoxin. The most suitable models were the Hill model for ZEA, the Langmuir model for AFB(1), and the Freundlich model for OTA. From these models, original mathematical affinity criteria were defined to quantify the product adsorption performances for each mycotoxin. The best yeast product, a yeast cell wall from baker's yeast, can adsorb up to 68% of ZEA, 29% of AFB(1), and 62% of OTA, depending on the mycotoxin concentrations. The adsorption capacity largely depended both on yeast composition and mycotoxin, but no direct correlation between yeast composition and adsorption capacity was found, confirming that adsorption of mycotoxin on yeast-based products involves complex phenomena. The results of this study are useful for comparing the adsorption efficiency of various yeast products and understanding the mechanisms involved in adsorption.     

电子鼻融合BP神经网络预测玉米赤霉烯酮和黄曲霉毒素B1含量模型研究

为探究玉米赤霉烯酮和黄曲霉毒素B_1的无损快速定量测定方法,用电子鼻对7级不同霉变程度玉米样品进行检测,并用理化分析方法分别测定霉变玉米中的玉米赤霉烯酮与黄曲霉毒素B_1含量;在提取电子鼻响应信号的积分值作为特征参量的前提下,采用BP神经网络建立不同霉变程度下玉米样品中的玉米赤霉烯酮与黄曲霉毒素B_1含量的预测模型。同时,为了获得较为可靠的BP神经网络预测模型,在神经网络结构不变的条件下,对比分析了不同训练集、测试集构建的预测模型。结果发现在各预测模型的70组测试样本中,相对误差控制在5%以内的样本数量都在60个以上,最大相对误差控制在15%以内,从而证明了BP神经网络预测模型的有效性、可靠性。该研究为实施玉米霉变毒素的快速无损检测提供了一种途径。     

高产酯酿酒酵母与乳酸菌共发酵过程中的相互作用研究

酵母菌和乳酸菌是各种酿酒生产中两类非常重要的发酵微生物,其相互作用对酒的产量和质量有很大影响。本试验主要研究了高产酯酿酒酵母MY-15和酿酒过程中三种常见乳酸菌（Lactobacillus casei lca、Pediococcus pentosaceus L1和Bacillus coagulans NJ）在生长和代谢方面相互间的影响。结果表明,乳酸菌对高产酯酿酒酵母MY-15的生长和产乙酸乙酯有明显的抑制作用,对产酒的影响不大;但乳酸菌的代谢产物乳酸对酿酒酵母的生长和代谢有明显的抑制作用。高产酯酿酒酵母MY-15对干酪乳杆菌lca的生长抑制作用明显,但少量的酵母菌对戊糖片球菌L1和凝结芽孢杆菌NJ的生长有促进作用;随着酵母菌接种量的增加,乳酸菌代谢乳酸呈先增后减的趋势;酵母菌代谢产物乙醇对乳酸菌的生长和代谢,在乙醇含量少于7.5%（V/V）时,抑制作用不明显;当酒精含量达17.5%（V/V）时,乳酸菌的生长被完全抑制。     

进口玉米酒糟粕中15种真菌毒素的检测和风险分析

建立了液相串联质谱检测玉米酒糟粕中15种真菌毒素的检测方法,并对结果分布进行了讨论。检测的真菌毒素包括黄曲霉毒素B1等15种真菌毒素。这些毒素采用溶剂提取,多功能净化柱净化,液相串联质谱检测。方法均经过优化和验证,满足进口玉米酒糟粕的检测要求。对67个进口玉米酒糟粕样品的检测结果表明,玉米赤霉烯酮、脱氧雪腐镰刀菌烯醇、T-2毒素、HT-2毒素等真菌毒素均有检出。本试验对这些数据进行了统计分析,提出了对进口玉米酒糟粕的真菌毒素风险分析结果。