粮食中主要真菌毒素及分析方法研究进展

真菌毒素是由某些真菌在适宜条件下产生的有毒次级代谢产物。在粮食中危害严重并持续引起全球食品安全问题的真菌毒素包括黄曲霉毒素、玉米赤霉烯酮、伏马菌素、赭曲霉毒素和脱氧雪腐镰刀菌烯醇,许多国家和地区对这些毒素在粮食中的含量制定了严格的限量要求,在成分复杂的粮食样本中有效提取真菌毒素并进行灵敏准确的检测非常重要。本文介绍了粮食中污染的主要真菌毒素,归纳了粮食中真菌毒素的样本前处理方法和检测方法,并结合实际应用分析了各种方法的优劣,预测了粮食中真菌毒素分析方法的发展方向,为真菌毒素的防控提供理论参考。     

Advantages and drawbacks of immunoaffinity columns in analysis of mycotoxins in food

A number of countries are setting legislations on mycotoxins. In order to reduce dispute between importing and exporting countries, the analytical data should be as comparable as possible, especially when levels are close to the regulatory limits. The present trend in the analysis of mycotoxins is to use immunoaffinity column (IAC) as a clean-up and enrichment technique, and Association of Official Analytical Chemists and European Union have validated methods which address a few food commodities. This study describes our experience using both conventional and IAC approaches in the analysis of three mycotoxins. Aflatoxins (AFs): Aflatoxin G1 has been detected by liquid-liquid partitioning methods with HPLC detection as false-positive in some maize. On IACs, this compound behaves as an AF, lowering the amount of the AFs trapped. The problem was solved using either TLC or HPLC with detection in the Kobra cell. Depending on the additives to food during the processing and cooking, the AFs might appear as an opened ring not recognised by the antibody. Fumonisins (FB): Compounds interfering with the FB's antibodies were also observed while analysing breakfast cereals leading to underestimation of FB. Ochratoxin A (OTA): Depending on the food composition and extraction techniques, OTA is underestimated with IAC in some breakfast cereals and coffee. These data strengthen the necessity to validate methods using IAC for each complex matrix.     

Effects of processing on mycotoxin stability in cereals

The mycotoxins that generally occur in cereals and other products are not completely destroyed during food‐processing operations and can contaminate finished processed foods. The mycotoxins most usually associated with cereal grains are aflatoxins, ochratoxins, deoxynivalenol, zearalenone and fumonisins. The various food processes that may have effects on mycotoxins include cleaning, milling, brewing, cooking, baking, frying, roasting, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize high temperatures having the greatest effects. In general, the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. This review focuses on the effects of various thermal treatments on mycotoxins. © 2014 Society of Chemical Industry     

PCR detection of Alternaria spp. in processed foods, based on the internal transcribed spacer genetic marker

The genus Alternaria is considered one of the most important fungal contaminants of vegetables, fruits, and cereals, producing several mycotoxins that can withstand food processing methods. Conventional methods for Alternaria identification and enumeration are laborious and time-consuming, and they might not detect toxigenic molds inactivated by food processing. In this study, a PCR method has been developed for the rapid identification of Alternaria spp. DNA in foodstuffs, based on oligonucleotide primers targeting the internal transcribed spacer (ITS) 1 and ITS2 regions of the rRNA gene. The specificity of the Alternaria-specific primer pair designed (Dir1ITSAlt-Inv1ITSAlt) was verified by PCR analysis of DNA from various Alternaria spp., and also from several fungal, bacterial, yeast, animal, and plant species. The detection limit of the method was 10(2) CFU/ml in viable culture, heated culture, or experimentally inoculated tomato pulp. The applicability of the method for detection of Alternaria spp. DNA in foodstuffs was assessed by testing several commercial samples. Alternaria DNA was detected in 100% of spoiled tomato samples, 8% of tomato products, and 36.4% of cereal-based infant food samples analyzed.     

Traditionally Processed Beverages in Africa: A Review of the Mycotoxin Occurrence Patterns and Exposure Assessment

African traditional beverages are widely consumed food‐grade liquids processed from single or mixed grains (mostly cereals) by simple food processing techniques, of which fermentation tops the list. These beverages are very diverse in composition and nutritional value and are specific to different cultures and countries. The grains from which home‐processed traditional beverages are made across Africa are often heavily contaminated with multiple mycotoxins due to poor agricultural, handling, and storage practices that characterize the region. In the literature, there are many reports on the spectrum and quantities of mycotoxins in crops utilized in traditional beverage processing, however, few studies have analyzed mycotoxins in the beverages themselves. The available reports on mycotoxins in African traditional beverages are mainly centered on the finished products with little information on the process chain (raw material to final product), fate of the different mycotoxins during processing, and exposure estimates for consumers. Regulations targeting these local beverages are not in place despite the heavy occurrence of mycotoxins in their raw materials and the high consumption levels of the products in many homes. This paper therefore comprehensively discusses for the 1st time the available data on the wide variety of African traditional beverages, the mycotoxins that contaminate the beverages and their raw materials, exposure estimates, and possible consequent effects. Mycotoxin control options and future directions for mycotoxin research in beverage production are also highlighted.     

A review of postharvest approaches to reduce fungal and mycotoxin contamination of foods

Contamination of agricultural and food products by some fungi species that produce mycotoxins can result in unsafe food and feed. Mycotoxins have been demonstrated to have disease‐causing activities, including carcinogenicity, immune toxicity, teratogenicity, neurotoxicity, nephrotoxicity, and hepatotoxicity. Most of mycotoxins are heat stable and cannot be easily destroyed by conventional thermal food processing or domestic cooking methods. Postharvest approaches to prevent growth of mycotoxin‐producing fungi and detoxify mycotoxins from contaminated food are important topics in food safety research. Physical, chemical, and biological methods have been applied to prevent fungal growth or mycotoxin production, or to reduce mycotoxin content in the postharvest period and contribute toward mitigating against the effects of mycotoxins on human health. This literature review aims to evaluate postharvest approaches that have been applied to control both fungi growth and mycotoxin content in food and discuss their potential for upscaling to industrial scale.     

The Fate of Mycotoxins During the Processing of Wheat for Human Consumption

Mycotoxins are a potential health threat in cereals including wheat. In the European Union (EU), mycotoxin maximum levels are laid down for cereal raw materials and final food products. For wheat and wheat‐based products, the EU maximum levels apply to deoxynivalenol (DON), zearalenone, aflatoxins, and ochratoxin A. This review provides a comprehensive overview on the different mycotoxins and their legal limits and on how processing of wheat can affect such contaminants, from raw material to highly processed final products, based on relevant scientific studies published in the literature. The potential compliance with EU maximum levels is discussed. Of the four mycotoxins regulated in wheat‐based foods in the EU, most data are available for DON, whereas aflatoxins were rarely studied in the processing of wheat. Furthermore, available data on the effect of processing are outlined for mycotoxins not regulated by EU law—including modified and emerging mycotoxins—and which cover DON derivatives (DON‐3‐glucoside, mono‐acetyl‐DONs, norDONs, deepoxy‐DON), nivalenol, T‐2 and HT‐2 toxins, enniatins, beauvericin, moniliformin, and fumonisins. The processing steps addressed in this review cover primary processing (premilling and milling operations) and secondary processing procedures (such as fermentation and thermal treatments). A special focus is on the production of baked goods, and processing factors for DON in wheat bread production were estimated. For wheat milling products derived from the endosperm and for white bread, compliance with legal requirements seems to be mostly achievable when applying good practices. In the case of wholemeal products, bran‐enriched products, or high‐cereal low‐moisture bakery products, this appears to be challenging and improved technology and/or selection of high‐quality raw materials would be required.     

食品与饲料基质中真菌毒素检测技术研究进展

真菌毒素是真菌在生长繁殖过程中产生的相对分子质量较小的次生有毒代谢产物,不易被加工或烹调加热所破坏,超过一定摄入量后会引起人的肝肾功能下降、癌变或诱发免疫抑制性疾病。目前尚无绝对有效的措施避免真菌毒素的污染,因此,研究可以准确高效地测定食品和饲料基质中的真菌毒素的检测技术非常重要。本研究通过对真菌毒素提取方法、净化方法及检测技术的研究进展进行综述,发现目前研究方法大多是针对某一种真菌毒素进行检测的常规检测方法或者同时检测多种真菌毒素的检测方法,由于这些方法存在稳定性差、定量不准确或前处理复杂等,因此未来应大力开发检测快速、高灵敏度、高特异性的真菌毒素检测方法。     

The fate of mycotoxins during secondary food processing of maize for human consumption

Mycotoxins are naturally occurring fungal metabolites that are associated with health hazards and are widespread in cereals including maize. The most common mycotoxins in maize that occur at relatively high levels are fumonisins (FBs), zearalenone, and aflatoxins; furthermore, other mycotoxins such as deoxynivalenol and ochratoxin A are frequently present in maize. For these toxins, maximum levels are laid down in the European Union (EU) for maize raw materials and maize-based foods. The current review article gives a comprehensive overview on the different mycotoxins (including mycotoxins not regulated by EU law) and their fate during secondary processing of maize, based on the data published in the scientific literature. Furthermore, potential compliance with the EU maximum levels is discussed where appropriate. In general, secondary processing can impact mycotoxins in various ways. Besides changes in mycotoxin levels due to fractionation, dilution, and/or concentration, mycotoxins can be affected in their chemical structure (causing degradation or modification) or be released from or bound to matrix components. In the current review, a special focus is set on the effect on mycotoxins caused by different heat treatments, namely, baking, roasting, frying, (pressure) cooking, and extrusion cooking. Production processes involving multiple heat treatments are exemplified with the cornflakes production. For that, potential compliance with FB maximum levels was assessed. Moreover, effects of fermentation of maize matrices and production of maize germ oil are covered by this review.     

Novel non-thermal food processing techniques and their mechanism of action in mycotoxins decontamination of foods

This review describes the major food and feed contaminating mycotoxins and provides a thorough insight about non-thermal food processing techniques and their mycotoxin detoxification mechanisms. Cold plasma, pulsed light, pulsed electric field, high pressure processing, and electron beam irradiation are among the techniques discussed. Mycotoxins decontamination is usually achieved through the release of reactive species and inactivation of toxin-producing microorganisms through alteration of cell membrane integrity and genetic makeup. Destruction of the molecular structure of mycotoxins responsible for toxicity also occurs during these processes. These non-thermal methods are effective in decontaminating mycotoxins with varying degrees of efficiency, and some of the methods do complete decontamination of mycotoxins with minimal processing. Despite their promising efficacy in decontaminating mycotoxins, the feasibility of most of these methods requires scale-up with future potential for commercialization and acceptance. Efforts should be made to increase the scalability and adoption of the technologies, especially in low-income countries where mycotoxin contamination is prevalent.     

Decontamination and detoxification strategies for the Fusarium mycotoxin deoxynivalenol in animal feed and the effectiveness of microbial biodegradation

Trichothecenes are a group of mycotoxins mainly produced by fungi of the Fusarium genus. Deoxynivalenol (DON) is one of the most abundant and important trichothecenes in food and feed, and is a significant contaminants due to its frequent occurrence in toxicologically relevant concentrations worldwide. Since toxin production depends strongly on environmental conditions, such as temperature and humidity, Fusarium toxin contamination can not be avoided completely. Therefore, exposure to this toxin is a permanent health risk for both humans and farm animals. As cereal crops are commonly contaminated with DON and animal diets consist mainly of cereals, it can be assumed that animals are frequently exposed to DON-contaminated feeds. Many strategies can be undertaken to reduce the toxic effect of DON. In addition to the general necessity for minimizing all risk factors that might influence the contamination of cereals with DON, such as the so-called field toxins before harvest, several post-harvest strategies can be applied to counteract possible deleterious effects of this mycotoxin in farm animals. Another approach for decontamination in feedstuffs is the use of adsorbent materials. Adsorbent materials may bind mycotoxins in the gastrointestinal tract and reduce absorption and systemic toxicity. It has been shown that some adsorbents are suitable to alleviate the toxic effects of specific mycotoxins, but its efficacy against trichothecenes is practically zero. Therefore, alternative strategies to reduce animal and human health risk are needed. The use of microbial additives is a method which uses microorganisms having the capability to detoxify mycotoxins by metabolism or degradation prior to their resorption in the gastrointestinal tract. DON has been reported to be completely transformed to de-epoxy-DON by ruminal and intestinal microflora. Eubacterium BBSH 797 was capable of DON degradation and counteracted the toxic effects of DON in animals. This review focuses on the efficacy of microbial feed additives in ameliorating the toxic effects of DON. According to the results of experiments to date, it appears that microorganisms are the main living organisms suitable for this mycotoxin biodegradation. However, the use of this approach depends on its effectiveness from both a practical and economic perspective.     

低温等离子体在食品中杀灭微生物与降解真菌毒素研究进展

低温等离子体作为一种新型的食品加工处理方法,在提高产品安全性、延长食品保质期方面具有广阔的应用前景。低温等离子体的作用机制决定其可以在低温状态下快速杀灭微生物、降解各类真菌毒素且不会留下任何已知的化学残留物。因此,该文重点概述低温等离子体的作用机理与方式,对微生物和真菌毒素的杀灭与降解效果及作用机制,并总结其在新鲜农产品、液体食品、粮食和肉类等多个产业中杀菌及降解真菌毒素方面的研究进展,以期为现有研究工作提供方法与思路。     

A review on novel non-thermal food processing techniques for mycotoxin reduction

The overarching challenges of mycotoxin contamination in food necessitate the development of strategies to be implemented to combat their effects thereof. Common processing techniques have been utilised but do not necessarily meet the desired efficacy. This review appraises studies on novel non-thermal food processing techniques, particularly high pressure processing, pulsed electric filed, cold plasma and ultrasound processing for the decontamination of mycotoxins in food. Although available studies on these techniques have suggested a reduction of mycotoxins and in some instances, complete decontamination of mycotoxins was also reported. The mechanisms by which reduction/elimination occurs include through decomposition of toxins after collision with ions/electrons leading to cleavage of bonds, structural degradation of the mycotoxins structure and cleavage of functional groups. Additional studies into the toxicity of degraded products and the composition of the food products are still required to ensure a more widespread adoption of these techniques to enhance food safety.     

消减食品加工过程中的真菌毒素：来自欧洲和东南亚的经验分享（网络首发、推荐阅读）

在世界范围内,由真菌毒素造成的经济损失估计达数十亿美元,给人类和动物带来安全风险。粮食中真菌毒素的预防可以通过食品加工过程中进行真菌毒素的消减处理。在过去几十年里,虽然发表的科技论文中报道了大量真菌毒素防控措施,但实际生产往往需要更容易实施的、简单易行的建议和指导方针。欧洲和东南亚在真菌毒素处理到数据分析、风险评估到污染防控、差异分析到流通途径等方面可以做到相互协作,互相补充。欧洲和东南亚政府及相关行业必须在综合考虑地域、农业系统和不同国家消费者偏好的背景下,寻求平衡食品安全和地区贸易二者关系,协同管控食品供应链。以谷物为例,加工过程包括初级加工（谷物清理和碾磨操作）和二次加工（如烘焙过程中的发酵和烘烤）,欧洲尤其关注烘焙食品安全性及全麦面包生产工艺对呕吐毒素的影响。结合农业、咖啡工业和科学研究人员的专业知识及亚洲咖啡生产者的具体情况,重点关注东南亚地区咖啡中赭曲霉毒素A污染问题。在农场环境中减少真菌毒素的措施给咖啡农民带来了较大的挑战,包括在规范种植农场模式下咖啡生产者和消费者之间社会经济效益和个人行为模式的相关影响因素。随着世界变得更加全球化,食品和饲料供应链也变得日趋复杂,因此,需要制定更全面的策略来确保食品供给及品质安全。     

Extrusion processing of raw food materials and by-products: A review

ABSTRACT

Extrusion technology has rapidly transformed the food industry with its numerous advantages over other processing methods. It offers a platform for processing different products from various food groups by modifying minor or major ingredients and processing conditions. Although cereals occupy a large portion of the extruded foods market, several other types of raw materials have been used. Extrusion processing of various food groups, including cereals and pseudo cereals, roots and tubers, pulses and oilseeds, fruits and vegetables, and animal products, as well as structural and nutritional changes in these food matrices are reviewed. Value addition by extrusion to food processing wastes and by-products from fruits and vegetables, dairy, meat and seafood, cereals and residues from starch, syrup and alcohol production, and oilseed processing are also discussed. Extrusion presents an economical technology for incorporating food processing residues and by-products back into the food stream. In contemporary scenarios, rising demand for extruded products with functional ingredients, attributed to evolving lifestyles and preferences, have led to innovations in the form, texture, color and content of extruded products. Information presented in this review would be of importance to processors and researchers as they seek to enhance nutritional quality and delivery of extruded products.     

焙烤制品生产中的过敏原及其控制体系研究进展

食品过敏问题已成为一项重要的食品安全危害,本文对焙烤制品国内外有关过敏原法律法规和国际对过敏原控制相关要求进行整理,并进行汇总分析,结合焙烤制品生产加工过程中所用原辅料及产品标识,识别了焙烤制品加工中存在含麸质的谷类-如全麦粉等、蛋类及其制品-鸡蛋、蛋液、蛋粉等、花生及其制品-如花生碎、花生片等、乳及其制品-如鲜奶、奶粉、乳清粉等、坚果及其制品-如杏仁、核桃仁等、芝麻及其制品如芝麻等是焙烤制品中的过敏原。从过敏原识别、原辅材料采购控制、加工过程交叉污染的控制、贮藏运输过程防止交叉污染控制、准确标签标识、产品可追溯及人员培训六方面提出了焙烤制品过敏原的系统控制体系。     

Potential of Machine Vision Techniques for Detecting Fecal and Microbial Contamination of Food Products: A Review

Consumption of mycotoxin-contaminated agricultural and food products has caused adverse human health effects for many centuries. Although mycotoxin contamination of agricultural products still occurs, application of innovative agricultural practices, food processing, and handling techniques has greatly reduced consumer exposure to mycotoxins. This paper reviews recent developments and potential applications of machine vision systems in replacing current labor-intensive, time-consuming methods by providing a quick, accurate, and low-cost alternative for detecting microbial and fecal contaminants in fresh and processed foods. The basic principles and components of the machine vision system are also discussed.     

Recent progress in mycotoxins detection based on surface-enhanced Raman spectroscopy

Mycotoxins are toxic compounds naturally produced by certain types of fungi. The contamination of mycotoxins can occur on numerous foodstuffs, including cereals, nuts, fruits, and spices, and pose a major threat to humans and animals by causing acute and chronic toxic effects. In this regard, reliable techniques for accurate and sensitive detection of mycotoxins in agricultural products and food samples are urgently needed. As an advanced analytical tool, surface-enhanced Raman spectroscopy (SERS), presents several major advantages, such as ultrahigh sensitivity, rapid detection, fingerprint-type information, and miniaturized equipment. Benefiting from these merits, rapid growth has been observed under the topic of SERS-based mycotoxin detection. This review provides a comprehensive overview of the recent achievements in this area. The progress of SERS-based label-free detection, aptasensor, and immunosensor, as well as SERS combined with other techniques, has been summarized, and in-depth discussion of the remaining challenges has been provided, in order to inspire future development of translating the techniques invented in scientific laboratories into easy-to-operate analytic platforms for rapid detection of mycotoxins.     

A critical review of biological methods for the detection of fungal toxins in foods and foodstuffs

Many biological assays (bioassays) have been developed to detect fungal toxins (mycotoxins). Few of these assays are as sensitive to mycotoxins as chemical assays or have been shown to be able to detect a wide range of different mycotoxins. Bioassays also suffer from a number of other problems including interference by nonfungal agents and from often being slow and less reproducible than chemical assays for mycotoxins. Bioassays have given little valuable information in their use in the surveillance of food and foodstuffs. Their major value has been in the initial identification and isolation of mycotoxins.     

Thermal stability of T-2 and HT-2 toxins during biscuit- and crunchy muesli-making and roasting

ABSTRACT

The mycotoxins T-2 and HT-2 toxin are frequently occurring food contaminants which are produced by Fusarium species. Humans and animals are mainly exposed to these substances by the consumption of contaminated oats, maize and wheat. For the production of crunchy muesli, bread and bakery products, these cereals undergo multiple processing steps, including baking, roasting and extrusion cooking. However, the influence of food processing on T-2 and HT-2 toxin levels is to date poorly understood. Thus, the effects of baking and roasting on both mycotoxins were evaluated during biscuit-, crunchy muesli- and toasted oat flakes-production under precise variation of various parameters: heating time and temperature as well as recipe formulation were varied in the range they are applied in the food processing industry. Therefore, oatmeal or flaked oats were artificially contaminated individually with both toxins and processed at the laboratory scale. T-2 toxin generally showed a higher degradation rate than HT-2 toxin. During biscuit-making up to 45% of T-2 toxin and 20% of HT-2 toxin were thermally degraded, showing a dependency on water content, baking time and temperature. The preparation of crunchy muesli yielded no significant toxin degradation which is probably due to the low temperatures applied. Roasting led to a degradation of 32% of T-2 toxin and 24% of HT-2 toxin. Taken together, both mycotoxins are partially degraded during thermal food processing; the degradation rates are influenced by the food composition and processing parameters.