Occurrence and significance of mycotoxins in forage crops and silage: a review

Study of mycotoxins in animal feeding stuffs has concentrated on the occurrence of aflatoxins and, to a lesser extent, other mycotoxins in cereals, raw materials and concentrate feeds. However, ruminant diets contain a high proportion of forage crops such as grass or maize silage, hay and straw. Under adverse growing, production or storage conditions, fungal spoilage is likely to occur with some degree of mycotoxin contamination. The mould flora of forage crops is likely to differ significantly from that of cereals and mycotoxin contamination, should it occur, could differ qualitatively and quantitatively. Information relating to forage crops as a potential source of mycotoxins is reviewed. Some field incidents and animal disease which may be mycotoxin related are discussed and analytical methods are reviewed. Information on dose and effect of candidate mycotoxins is given where available. The review suggests areas which the authors consider merit further study. Crown Copyright 1998.     

乳酸菌对真菌毒素的减毒研究进展

真菌毒素是由多种真菌产生的有毒次生代谢产物，它们对食品和饲料的污染已经给人和动物的健康造成了潜在的危害。乳酸菌作为去除真菌毒素的一种替代策略，在大规模、低成本的食品减毒方面显示出良好的潜力。本文总结了食品中几种主要真菌毒素的特征，从乳酸菌对真菌毒素产生的抑制、体外吸附、体内毒性缓解等方面概述相关国内外研究进展，并关注乳酸菌减毒在食品体系中的应用，以期为乳酸菌在食品和饲料中作为真菌毒素天然清除剂的应用提供理论参考。     

Mycotoxins: Current situation

Abstract

Mycotoxins are toxic secondary metabolites of fungi which affect humans and other animals. There are over 300 mycotoxins currently known, and of these only a few have been studied well. Aflatoxin B₁, the major member of aflatoxins and one of the most potent hepatocarcinogens known in nature, is the most well‐studied mycotoxin. In addition to aflatoxins, trichothecenes have been studied from the late 1970s. Natural contamination of various foods and feedstuffs with mycotoxins has been reported from all over the world. Several human and animal intoxications by mycotoxins were reported, such as “turkey's X disease,” alimentary toxic alecukia, and “yellow rain.” Because of concern for human health, many countries have set tolerances for some mycotoxins in foods and feeds, and the number of regulations concerning mycotoxins is increasing.     

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.     

粮食真菌毒素污染的预防与脱毒

粮食真菌毒素的预防包括预防粮食作物田间生长及收获后储藏过程中毒素的生物合成及代谢。真菌毒素的脱毒主要指除去、破坏及减少毒素作用的收获后处理。田间及储藏中没能有效控制真菌毒素的合成必将导致对人类健康的危害及经济损失，而有效的监控将避免真菌毒素成为威胁人类健康的污染源。应用综合预防措施将是控制真菌毒素的有效策略。本文强调的收获前后措施将依特别年份的特定的气候条件而定。弄清适于真菌污染、生长和产毒环境因素是有效控制食物及饲料中真菌毒素的关键措施。有很多新的有效的收获前预防策略正在开发，如利用转基因技术创造粮食作物抗性新品种及利用非产毒真菌菌株生物防治等。收获后的防止真菌毒素产生主要依赖于收获前后的良好的管理措施。脱毒策略可分为物理、化学或微生物脱毒技术，这些脱毒技术主要通过破坏、修饰或吸附真菌毒素，从而达到减少或消除毒素作用。     

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.     

A Review on Mycotoxins in Food and Feed: Malaysia Case Study

Fungi are distributed worldwide and can be found in various foods and feedstuffs from almost every part of the world. Mycotoxins are secondary metabolites produced by some fungal species and may impose food safety risks to human health. Among all mycotoxins, aflatoxins (AFs), ochratoxin A (OTA), trichothecenes, deoxynivalenol (DON and T‐2 toxin), zearalenone (ZEN), and fumonisins (FMN) have received much attention due to high frequency and severe health effects in humans and animals. Malaysia has heavy rainfall throughout the year, high temperatures (28 to 31 °C), and high relative humidity (70% to 80% during wet seasons). Stored crops under such conditions can easily be contaminated by mycotoxin‐producing fungi. The most important mycotoxins in Malaysian foods are AFs, OTA, DON, ZEN, and FMN that can be found in peanuts, cereal grains, cocoa beans, and spices. AFs have been reported to occur in several cereal grains, feeds, nuts, and nut products consumed in Malaysia. Spices, oilseeds, milk, eggs, and herbal medicines have been reported to be contaminated with AFs (lower than the Malaysian acceptable level of 35 ng/g for total AFs). OTA, a possible human carcinogen, was reported in cereal grains, nuts, and spices in Malaysian market. ZEN was detected in Malaysian rice, oat, barley, maize meal, and wheat at different levels. DON contamination, although at low levels, was reported in rice, maize, barley, oat, wheat, and wheat‐based products in Malaysia. FMN was reported in feed and some cereal grains consumed in Malaysia. Since some food commodities are more susceptible than others to fungal growth and mycotoxin contamination, more stringent prevention and control methods are required.     

茶叶中真菌毒素污染的国内外研究概况

本文综述了国内外与茶叶真菌毒素污染有关的研究,结果表明,红茶、绿茶、白茶和黑茶都可能污染真菌和真菌毒素,应引起我国相关部门的重视。为降低真菌毒素污染茶叶的风险,建议加强茶叶毒素检测,普查各类茶叶真菌毒素污染情况;应用过程控制原理,筛选不产毒素菌株发酵黑茶,监测发酵过程,建立安全的黑茶发酵技术体系。     

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.     

Further mycotoxin effects from climate change

Climate change will affect mycotoxins in food. The 2007 Intergovernmental Panel on Climate Change report is reinterpreted herein to account for what may occur with mycotoxins. Warmer weather, heat waves, greater precipitation and drought will have various impacts, depending on which regions of the world and mycotoxin systems are considered. The humidity issues are more complex as some areas will experience drought and others greater precipitation: in vivo data on the effects of moisture on mycotoxins in crops are more ambiguous than those for temperature. In vitro data on fungal growth and mycotoxin production may not relate directly to the situation in the field or post harvest, but are useful for base-line assumptions. The effects of climate in various regions of the world, i.e. Africa, Europe, Asia, Latin America and North America are considered in terms of mycotoxin contamination. Crops introduced to exploit altered climate may be subject to fewer mycotoxin producing fungi (the “Parasites Lost” phenomenon). Increased mycotoxins and UV radiation may cause fungi to mutate on crops and produce different mycotoxins. Whereas there is relevant information on aflatoxins, deoxynivalenol, and ochratoxin A, more mycotoxins require to be considered: Data on patulin are missing. The current paper considers uniquely ergot alkaloids. Amelioration strategies are provided. There is considerable urgency in the need to address these issues.     

Mycotoxin problem in Africa: current status, implications to food safety and health and possible management strategies

Mycotoxins are toxic secondary metabolites of fungal origin and contaminate agricultural commodities before or under post-harvest conditions. They are mainly produced by fungi in the Aspergillus, Penicillium and Fusarium genera. When ingested, inhaled or absorbed through the skin, mycotoxins will cause lowered performance, sickness or death on humans and animals. Factors that contribute to mycotoxin contamination of food and feed in Africa include environmental, socio-economic and food production. Environmental conditions especially high humidity and temperatures favour fungal proliferation resulting in contamination of food and feed. The socio-economic status of majority of inhabitants of sub-Saharan Africa predisposes them to consumption of mycotoxin contaminated products either directly or at various points in the food chain. The resulting implications include immuno-suppression, impaired growth, various cancers and death depending on the type, period and amount of exposure. A synergistic effect between mycotoxin exposure and some important diseases in the continent such as malaria, kwashiorkor and HIV/AIDS have been suggested. Mycotoxin concerns have grown during the last few decades because of their implications to human and animal health, productivity, economics of their management and trade. This has led to development of maximum tolerated limits for mycotoxins in various countries. Even with the standards in place, the greatest recorded fatal mycotoxin-poisoning outbreak caused by contamination of maize with aflatoxins occurred in Africa in 2004. Pre-harvest practices; time of harvesting; handling of produce during harvesting; moisture levels at harvesting, transportation, marketing and processing; insect damage all contribute to mycotoxin contamination. Possible intervention strategies include good agricultural practices such as early harvesting, proper drying, sanitation, proper storage and insect management among others. Other possible interventions include biological control, chemical control, decontamination, breeding for resistance as well as surveillance and awareness creation. There is need for efficient, cost-effective sampling and analytical methods that can be used for detection analysis of mycotoxins in developing countries.     

粮食饲料资源霉菌毒素检测技术

真菌毒素（Mycotoxin）是一类由真菌产生的毒性次代谢产物,它广泛污染农作物、食品及饲料等植物性产品,并最终影响到人们的食物消费安全.真菌毒素的检测和控制在食品安全体系尤其对于谷物饲料安全具有重要的地位.本文介绍了谷物饲料中真菌毒素的分析技术,这些技术在许多标准方法中已经被采用,由此形成的分析方法从实用性角度被分为快速检测方法和确证方法,并在食品分析中得到了广泛使用.同时,本文也对真菌毒素分析领域中一些需要改进的方面和将来的需求趋势做了简要的介绍.     

中国谷物真菌毒素污染研究现状

谷物易受多种真菌毒素污染且消费量巨大，是人畜真菌毒素的主要摄入来源。本文统计了2009年至今关于我国谷物中真菌毒素污染的研究报道，发现国内的研究大多集中在水稻、小麦和玉米，而杂粮作物少之又少。其中，水稻受真菌毒素污染情况较轻；小麦主要受镰刀菌毒素污染，尤其是脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮；玉米则易感染多种真菌毒素。此外，小杂粮薏米、燕麦、谷子和高粱也有不同程度的污染。为明确谷物质量安全隐患，有效缓解谷物中真菌毒素的污染，我们应进一步加强对重要杂粮作物中真菌毒素的监管力度，建立更全面的真菌毒素筛查方法，建设真菌毒素防控标准化体系，强化农民对真菌毒素防控的意识与技术。     

Natural Occurrence,Analysis, and Prevention of Mycotoxins in Fruits and their Processed Products

Mycotoxins are small toxic chemical products formed as the secondary metabolites by fungi that readily contaminate foods with toxins in the field or after harvest. The presence of mycotoxins, such as aflatoxins, ochratoxin A, and patulin, in fruits and their processed products is of high concern for human health due to their properties to induce severe acute and chronic toxicity at low-dose levels. Currently, a broad range of detection techniques used for practical analysis and detection of a wide spectrum of mycotoxins are available. Many analytical methods have been developed for the determination of each group of these mycotoxins in different food matrices, but new methods are still required to achieve higher sensitivity and address other challenges that are posed by these mycotoxins. Effective technologies are needed to reduce or even eliminate the presence of the mycotoxins in fruits and their processed products. Preventive measures aimed at the inhibition of mycotoxin formation in fruits and their processed products are the most effective approach. Detoxification of mycotoxins by different physical, chemical, and biological methods are less effective and sometimes restricted because of concerns of safety, possible losses in nutritional quality of the treated commodities and cost implications. This article reviewed the available information on the major mycotoxins found in foods and feeds, with an emphasis of fruits and their processed products, and the analytical methods used for their determination. Based on the current knowledge, the major strategies to prevent or even eliminate the presence of the mycotoxins in fruits and their processed products were proposed.     

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

Fungi are commonly present in the environment and can grow under favorable conditions on an extensive variety of substrates. During harvesting, handling, storage, and distribution, agricultural commodities are subjected to infection by toxigenic molds, which may cause spoilage and produce toxic metabolites called mycotoxins. Fungal contamination of various food commodities with consequent exposure of the community to mycotoxins is a hazard that may exist depending on environmental factors, crop health, and soil conditions. Mycotoxins represent serious consequences due to substantial economic loss and risk to health. The environmental conditions of Pakistan with its mostly warm temperature are conducive to growth of toxigenic fungi resulting in mycotoxin production in different food items. Moreover, the poor conditions of storage and deficiency in regulatory measures in food quality control worsen the situation in the country. This review encompasses mycotoxin contamination of food and feed in Pakistan. High concentrations of mycotoxins are found in some commodities that are used on a daily basis in Pakistan, which may be a concern depending on dietary variety and health conditions of individuals in the population. Therefore, the mycotoxin contamination of foodstuff with exceeding levels represents a serious health hazard for the local population. There is a need to conduct more studies to analyze mycotoxin occurrence in all types of food commodities throughout the country. For consumer safety and the country's economy, the regulatory authorities should take into account this issue of contamination, and control strategies should be implemented and the quality control system of food improved.     

Mycotoxins in fruits,fruit juices,and dried fruits

This review gives an overview of the presence of mycotoxins in fruits. Although several mycotoxins occur in nature, very few (aflatoxins, ochratoxin A, patulin, Alternaria toxins) are regularly found in fruits. It has been shown that the presence of fungi on fruits is not necessarily associated with mycotoxin contamination. The formation of mycotoxins depends more on endogenous and environmental factors than fungal growth does. Mycotoxins may remain in fruits even when the fungal mycelium has been removed. Depending on the fruit and the mycotoxin, the diffusion of mycotoxins into the sound tissues of fruits may occur. The influence of the selection and storage of fruits and the influence of different processing steps involved in the production of fruit juices and dried fruits on possible mycotoxin contamination is described. It is shown that the careful selection, washing, and sorting of fruits is the most important factor in the reduction of mycotoxin contamination during the production of fruit juices. The processing of fruits does not result in the complete removal of mycotoxins.     

Aptasensors for mycotoxins in foods: Recent advances and future trends

Mycotoxin contamination in foods has posed serious threat to public health and raised worldwide concern. The development of simple, rapid, facile, and cost-effective methods for mycotoxin detection is of urgent need. Aptamer-based sensors, abbreviated as aptasensors, with excellent recognition capacity to a wide variety of mycotoxins have attracted ever-increasing interest of researchers because of their simple fabrication, rapid response, high sensitivity, low cost, and easy adaptability for in situ measurement. The past few decades have witnessed the rapid advances of aptasensors for mycotoxin detection in foods. Therefore, this review first summarizes the reported aptamer sequences specific for mycotoxins. Then, the recent 5-year advancements in various newly developed aptasensors, which, according to the signal output mode, are divided into electrochemical, optical and photoelectrochemical categories, for mycotoxin detection are comprehensively discussed. A special attention is taken on their strengths and limitations in real-world application. Finally, the current challenges and future perspectives for developing novel highly reliable aptasensors for mycotoxin detection are highlighted, which is expected to provide powerful references for their thorough research and extended applications. Owing to their unique advantages, aptasensors display a fascinating prospect in food field for safety inspection and risk assessment.     

粮食类饲料资源真菌毒素防制技术探讨

真菌毒素是一类有毒次级代谢物,对人畜健康有严重的影响,粮食饲料中一旦发生真菌毒素的污染,将对畜牧产品造成极大的经济损失.本文介绍了粮食饲料中真菌毒素的危害,并给出了可能的预防和控制措施.在真菌毒素控制方法中,根据它们降解毒素的不同原理,分成物理、化学、生物方法分别做了介绍.这些预防措施已经在一些领域使用.     

Silage review: Mycotoxins in silage: Occurrence,effects, prevention,and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.     

Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007–2016)

Major staple foods in Southern Africa are prone to mycotoxin contamination, posing health risks to consumers and consequent economic losses. Regional climatic zones favor the growth of one or more main mycotoxin producing fungi, Aspergillus, Fusarium and Penicillium. Aflatoxin contamination is mainly reported in maize, peanuts and their products, fumonisin contamination in maize and maize products and patulin in apple juice. Lack of awareness of occurrence and risks of mycotoxins, poor agricultural practices and undiversified diets predispose populations to dietary mycotoxin exposure. Due to a scarcity of reports in Southern Africa, reviews on mycotoxin contamination of foods in Africa have mainly focused on Central, Eastern and Western Africa. However, over the last decade, a substantial number of reports of dietary mycotoxins in South Africa have been documented, with fewer reports documented in Botswana, Lesotho, Malawi, Mozambique, Zambia and Zimbabwe. Despite the reported high dietary levels of mycotoxins, legislation for their control is absent in most countries in the region. This review presents an up-to-date documentation of the epidemiology of mycotoxins in agricultural food commodities and discusses the implications on public health, current and recommended mitigation strategies, legislation, and challenges of mycotoxin research in Southern Africa.