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.     

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.     

真菌毒素多重检测技术研究进展

真菌毒素分布广、污染重、防控难,从农田到餐桌的全过程均易污染农产品,严重威胁人畜健康和生态环境安全。据统计,农产品真菌毒素的污染中超过75%为多种真菌毒素的混合污染,因此建立高灵敏、高通量的真菌毒素检测技术成为当今食品安全检测领域普遍面临的重大挑战。本文综述了近5 年真菌毒素多重检测技术的研究进展,主要包括高效液相色谱-串联质谱法、免疫层析法、化学比色法、电化学法、化学发光法、荧光法、拉曼光谱法等,分析了这些方法在真菌毒素多重检测中的应用与亟待解决的问题,并对其未来的发展应用前景进行了展望。     

Occurrence and preventive strategies to control mycotoxins in cereal‐based food

Mycotoxins contamination in cereal‐based food is ubiquitous according to systematic review of the scientific documentation of worldwide mycotoxin contamination in cereal and their products between 2008 and 2018, thus representing food safety issue especially in developing tropical countries. Food processing plays a vital role to prevent mycotoxin contamination in food. Therefore, it is with great urgency to develop strategies to inhibit fungi growth and mycotoxin production during food processing. This review begins by discussing physicochemical properties of five most common mycotoxins (aflatoxins, fumonisins, ochratoxins, deoxynivalenol, and zearalenone) found in cereal grains, regulation for mycotoxins in food, and their potential negative impact on human health. The fate of mycotoxins during major cereal‐based food processing including milling, breadmaking, extrusion, malting, and brewing was then summarized. In the end, traditional mitigation strategies including physical and chemical and potential application of biocontrol agent and essential oil nanoemulsions that can be applied during food processing were discussed. It indicated that no single method is currently available to completely prevent mycotoxin contamination in cereal foods.     

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.     

植物油中真菌毒素污染的防控

真菌毒素都有强烈的毒性,有致癌、致畸、致突变作用。作为细菌的代谢产物,粮油制品中真菌毒素的污染不可避免。植物油是世界各地人们日常摄入的主要粮油制品,其安全关系到大众健康和社会稳定。植物油中真菌毒素污染是重要的食品安全隐患。本文从原料的种植、收割、储藏、加工等诸多方面介绍了植物油中真菌毒素污染状况及检测技术,并着重介绍了真菌毒素的防治,主要包括除毒和抑毒。实用、有效的植物油中真菌毒素污染的防控方法不仅可以减少国际贸易损失,更有助于保护消费者健康,是目前需要迫切发展的研究方向之一。     

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.     

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.     

Keeping mycotoxins away from the food: Does the existence of regulations have any impact in Africa?

Following the discovery of aflatoxins in the early 1960s, there have been many studies leading to the uncovering of many mycotoxins and the understanding of associated health effects in animals and humans. Consequently, there has been a global increase in the number of countries with mycotoxin regulations in foods. However, many African countries have only regulations for aflatoxins (or a few other mycotoxins) in specific foods, or no regulations at all. This paper critically reviews the challenges thwarting the establishment of mycotoxin regulations and their impacts on human dietary mycotoxin exposure in Africa. Mycotoxin regulatory limits for different countries are compared with mycotoxin tolerable daily intakes established by international food safety bodies taking into account consumption patterns. The agrarian setup, food insecurity, and mycotoxin analytical challenges in African countries are discussed; and more feasible mycotoxin dietary exposure reduction strategies are proposed.     

Mycotoxin Contamination of the Food Supply Chain - Implications for One Health Programme

Mycotoxins are a group of naturally occurring toxic chemical substances, produced by different fungal species, which can cause illness or even death due to their toxigenic, carcinogenic, mutagenic and teratogenic effects. Though more than 400 mycotoxins are known to have toxic effects on human when ingested along with contaminated food, mycotoxins like aflatoxins, ochratoxins, zeralenone, trichothecenes and fumonisins are the major mycotoxins influencing the public health and agriculture. Due to the global nature of the food supply and advances in analytical capabilities, mycotoxin contamination will continue to be an area of concern for regulatory agencies, the food industry, and consumers.     

粮食中脱氧雪腐镰刀菌烯醇风险预警研究进展

脱氧雪腐镰刀菌烯醇是小麦和玉米等粮食中常见的真菌毒素,受污染的粮食会严重影响人和动物健康,控制粮食产前镰刀菌感染和脱氧雪腐镰刀菌烯醇的积累是保障粮油食品安全的重要环节。当前,世界各国都十分重视粮食真菌毒素污染风险预警工作,粮食产前脱氧雪腐镰刀菌烯醇的污染预警研究近年来发展迅速,在脱氧雪腐镰刀菌烯醇积累的田间影响因素研究和建立产前风险预警模型中,都取得了一定进展。本文综述了脱氧雪腐镰刀菌烯醇风险预警的最新研究成果,旨在总结和整合现有的研究方法和成果,为开展我国粮食真菌毒素早期预警提供参考。     

真菌毒素检测与限量标准的现状与问题分析

真菌毒素是一类由丝状真菌在适宜条件下产生的有毒次级代谢产物, 极易污染粮谷类食品、食用油及乳制品等, 具有肝毒性、肾毒性、致畸性、致癌性、免疫抑制及破坏生殖系统等毒性, 对人体危害极大, 是继农药残留、兽药残留、重金属污染后, 影响农产品质量安全的又一类关键风险因子, 极大的制约了我国农产品的出口贸易, 同时也造成了我国食品安全的又一问题。本文重点介绍了农产品中真菌毒素的类型品种、毒性特点以及不同检验方法的适用范围、限量及检出限, 阐述了真菌毒素限量标准的研究进展和标准内容, 通过比对国内外真菌毒素的研究种类和进展, 分析目前真菌毒素污染现状及存在的问题, 提出应对策略, 对真菌毒素污染检测的发展进行了展望, 对今后保障饮食安全提供科学依据。     

Advances in Mycotoxin Research: Public Health Perspectives

Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause serious adverse effects in different organs including the liver, kidney, and immune system in humans. These toxic secondary metabolites are produced by filamentous fungi mainly in the genus Aspergillus, Penicillium, and Fusarium. It is challenging to control the formation of mycotoxins due to the worldwide occurrence of these fungi in food and the environment. In addition to raw agricultural commodities, mycotoxins tend to remain in finished food products as they may not be destroyed by conventional processing techniques. Hence, much of our concern is directed to chronic health effects through long‐term exposure to one or multiple mycotoxins from contaminated foods. Ideally risk assessment requires a comprehensive data, including toxicological and epidemiological studies as well as surveillance and exposure assessment. Setting of regulatory limits for mycotoxins is considered necessary to protect human health from mycotoxin exposure. Although advances in analytical techniques provide basic yet critical tool in regulation as well as all aspects of scientific research, it has been acknowledged that different forms of mycotoxins such as analogs and conjugated mycotoxins may constitute a significant source of dietary exposure. Further studies should be warranted to correlate mycotoxin exposure and human health possibly via identification and validation of suitable biomarkers.     

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.     

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。     

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.     

Distribution of mycotoxins and risk assessment of maize consumers in five agro-ecological zones of Nigeria

Many individuals are not only food insecure but chronically exposed to high levels of mycotoxins through their diets in many developing countries. Seventy composite samples of stored maize grains were collected from farmers’ storage structures in five agro-ecological zones (AEZs) of Nigeria where maize is predominantly produced between August 2011 and February 2012. The grains were analysed for mycotoxin contamination with the liquid chromatography tandem mass spectrometry method and mycotoxin occurrence maps constructed from the database of the distribution of the toxins. A risk assessment was also carried out in order to provide information on the extent of human exposure to the toxins. Twelve regulated mycotoxins with negative economic and public health consequences were detected in the maize grains across the AEZs at concentrations exceeding the maximum allowable limits including AFM₁ that was detected for the first time in Nigerian maize. There is a high risk of contamination of the stored grains by Nigerian consumers especially in the Derived and Southern Guinea Savannas, resulting in a national burden of between 126.85 and 38,682.29 DALYs. Intervention strategies are therefore needed across the AEZs to ensure that safe and wholesome foods are made available to the populace.     

便携式生物传感器在真菌毒素检测中的应用研究进展

食品在贮藏、运输和加工过程中易受真菌侵染。由真菌代谢所产生的真菌毒素对食品造成了严重的污染，并引发了严峻的食品安全问题。传统的检测方法大多需要大型精密仪器设备、繁琐的操作步骤以及专业技术人员，这在很大程度上限制了这些方法在现场即时检测中的应用。便携式传感器允许用户利用小型化设备实时监测真菌毒素的污染情况，具有操作简便、用户友好、检测速度快、灵敏度高等优点，受到越来越多的科研工作者及社会各界人士的青睐。本文重点对试纸条、个人血糖仪、手持式pH计、气压计、智能手机、微流控芯片以及基于可视化、电化学、等离子体等输出信号的便携式生物传感器在真菌毒素检测中的应用和发展前景进行综述，以期为真菌毒素新型便携式生物传感器的研发提供参考。     

Aflatoxigenic fungi and mycotoxins in food: a review

Abstract

Food contamination is a common phenomenon in the production, distribution and consumption of processed and agricultural commodities all over the world. Food safety is now taking the frontal stage in food production, processing and distribution. This study assessed the presence of aflatoxigenic fungi and mycotoxins in foods, occurrence, control, socio-economic and health implications. This study also gave comprehensive information on the safety and mycological quality of foods as well the effect on the people and economy of various countries. The review revealed the various aflatoxigenic fungi in foods, their distribution in agricultural produce and their effects on reduction in yield and quality with attendant consumer health implications and resulting significant economic losses. In developing countries, majority of the people do not know the inherent dangers of consuming mouldy produce or food contaminated with fungi and moulds with possible contamination by mycotoxigenic fungi because of lack of awareness about the danger involved. In view of this, there is need for general and public education to sensitise the people on the economic and health hazards posed by mycotoxins. Control measures such as good agricultural practices, crop selection, proper washing and cooking practices of food commodities should be emphasized to the people. Regulatory control, fast and effective analyses and detection, good produce handling and storage should be encouraged as this will assist in mitigating the side effects of mycotoxins in foods particularly in the tropical and sub-tropical countries, and in Africa nations where there is enabling environment that promotes fungal growth, shortage of food and drought of modern storage and processing infrastructures.     

粮食中隐蔽型真菌毒素污染的研究进展

真菌毒素污染是影响全球食品安全问题的重要因素之一。真菌毒素是真菌产生的次级代谢产物,对人体、动植物皆可产生危害。自然条件下,真菌毒素分子可与葡萄糖、丙二酸或谷胱甘肽等极性较强的基团结合,生成结合型真菌毒素。由于毒素结构发生改变,现有的常规检测手段不能有效地检测其存在,因此称其为隐蔽型真菌毒素(masked mycotoxins)。已有文献报道,隐蔽型真菌毒素往往与其原型同时存在于粮食中,而隐蔽型毒素在进入人和动物体内后,经水解、氧化还原等代谢过程,可释放出有毒的毒素原型分子,给食品安全、人和动物健康造成严重隐患。因此对隐蔽型真菌毒素的形成机制、污染状况和毒理研究应尽快展开。本文综述了国内外近几年以来几种常见隐蔽型真菌毒素的最新研究进展,为隐蔽型真菌毒素的研究提供有价值的参考。