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.     

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.     

Irradiation for Mold and Mycotoxin Control: A Review

The mycotoxin issue requires constant vigilance from economic, regulatory, and scientific agents to minimize its toxicological effects on human and animals. The implementation of good practices to avoid fungal growth and mycotoxin production on agricultural commodities is essential to achieve most restrictive safety standards; however, the contribution of novel technologies that may act on postharvesting and poststorage situations may be equally important. Several methodologies, more or less technologically advanced, may be used for this purpose. In this work, we review the role, contribution, and impact of irradiation technology to control the presence of fungi and mycotoxins in food and in feed. The effect of this technology on the viability of mold spores and on the elimination of mycotoxins is reviewed. A critical evaluation of the advantages and disadvantages of irradiation in this context is presented.     

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。     

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.     

Advanced synchrotron-based and globar-sourced molecular (micro) spectroscopy contributions to advances in food and feed research on molecular structure,mycotoxin determination,and molecular nutrition

ABSTRACT

Mycotoxin contamination has been a worldwide problem for food and feeds production for a long time. There is an obviously increased focus of the food and feed industry toward the reduction of mycotoxin concentration in both the raw materials and finished products. Therefore, both effective qualitative and quantitative techniques for the determination of mycotoxins are required to minimize their harmful effects. Conventional wet chemical methods usually are time-consuming, expensive, and rely on complex extraction and cleanup pretreatments. Synchrotron-based and globar-based molecular spectroscopy have shown great potential to be developed as rapid and nondestructive tools for the determination of molecular structure, molecular nutrition and mycotoxins in feed and food. This article reviews the common types of mycotoxins in feed and food, their toxicity, as well as the conventional detection methods. The principle of advanced molecular spectroscopy techniques and their application prospects for mycotoxin detection are discussed. Recent progress in food and feed research with molecular spectroscopy techniques is highlighted. This review provides a potential and insight into how to determine the structure and mycotoxins of feed and food on a molecular basis with advanced Synchrotron-based and globar-based molecular (micro) spectroscopy.     

The fate of mycotoxins during thermal food processing

Mycotoxins are considered to be heat‐stable molecules. Because of their toxic effects, information about their stability in thermal processes and potential inactivation procedures is needed. Numerous reports in the literature over a number of years have described the fate of mycotoxin during thermal food processing, including cooking, boiling, baking, frying, roasting and pasteurization. This review focuses on the effects of various thermal treatments on mycotoxins, while the fate of mycotoxins during extrusion processing, which is one of the most important technologies employed in the food industry, will also be reviewed. Copyright © 2009 Society of Chemical Industry     

镰刀菌属真菌毒素的毒性研究进展

镰刀属真菌毒素是非常重要的一类真菌毒素,其种类繁多,污染率高,性质差异大,毒性也较强。本综述总结了较为常见的28种镰刀属真菌毒素(T-2毒素、HT-2毒素、蛇形毒素、新茄病镰刀菌烯醇、雪腐镰刀菌烯醇、脱氧雪腐镰刀菌烯醇、镰刀菌烯酮、玉米赤霉烯酮、伏马毒素B_1、B_2、B_3、串珠镰刀菌素、白僵菌素以及恩镰孢菌素等)近40年来体内、体外毒性研究资料,主要涵盖急性毒性、慢性毒性的致癌性、生长生殖毒性、致突变和基因毒性、免疫毒性、神经毒性、细胞毒性及血液毒性。同时对伏马毒素B_1、脱氧雪腐镰刀菌烯醇及其他几种常见毒素间的协同毒性作用进行概述。体内毒性实验研究中主要采用口服和腹腔注射的给药方式;而最常用的实验动物为鸡、小鼠、大鼠和猪。体外毒性实验研究用细胞为:鼠伤寒沙门氏菌菌株、人类巨核红细胞祖细胞以及动物肾脏上皮细胞等。对此类真菌毒素毒性的总结,可进一步加深对毒素的认识,并为食品、饲料及中药安全性方面相关的法律法规制订提供重要依据。     

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.     

Review of mycotoxin reduction in food and feed: from prevention in the field to detoxification by adsorption or transformation

Mycotoxins are secondary metabolites present worldwide in agricultural commodities and produced by ?lamentous fungi that cause a toxic response (mycotoxicosis) when ingested by animals. Prevention of mycotoxicoses includes pre- and post-harvest strategies. The best way to reduce the mycotoxin content in food and feed is the prevention of mycotoxin formation in the ?eld, but this is often not sufficient, so other methods are needed. To decontaminate and/or detoxify mycotoxin-contaminated food and feed, the most prevalent approach in the feed industry is the inclusion of sorbent materials in the feed thus obtaining more or less selective removal of toxins by adsorption during passage through the gastrointestinal tract. Another reliable approach is to add enzymes or microorganisms capable of detoxifying some mycotoxins. Through a comprehensive review of published reports on the strategies for mycotoxin removal, this present work aims to update our understanding of mycotoxin removal. It provides an insight into the detoxification of mycotoxin present in food and feed. In the future, more emphasis needs to be placed on adsorption of mycotoxins in the gastrointestinal tract. Concerning the enzymatic transformation of mycotoxins, further efforts are required in understanding detoxification reactions, the toxicity of transformation products and in the characterization of enzymes responsible for transformations.     

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.     

Effect of Processing on Mycotoxin Content in Grains

Mycotoxins that commonly occur in cereal grains and other products can contaminate finished processed foods on account of their high toxicity. The mycotoxins that are commonly associated with food grains include aflatoxins, ochratoxin A, fumonisins, deoxynivalenol, and zearalenone. Various food-processing operations include sorting, trimming, cleaning, cooking, baking, frying, roasting, flaking, and extrusion that have variable effects on mycotoxins. The nature of the processing operation viz. physical, chemical, or thermal plays an important role in this; usually, the processes that utilize the higher temperatures have greater effects on mycotoxin dissipation. In general, the processes are known to reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing result in lowest mycotoxin concentrations, since these involve higher temperatures. It is observed that very high temperatures are needed to bring about high reduction in mycotoxin concentrations, approaching acceptable background levels. The treatment with chemicals like ammonia, bicarbonate, citric acid, or sodium bisulfite is also effective in resulting in significant decline in mycotoxin concentrations.     

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。     

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。     

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.     

Occurrence of total aflatoxins,ochratoxin A and deoxynivalenol in foodstuffs available on the Lebanese market and their impact on dietary exposure of children and teenagers in Beirut

Mycotoxins are fungal metabolites commonly present in food and constituting a potential threat to food safety. Total aflatoxins (AFT), ochratoxin A (OTA) and deoxynivalenol (DON) are among the most widespread mycotoxins. We assessed the occurrence of AFT, OTA and DON in some foodstuffs available on the Lebanese market and evaluated the potential risk to the health of children and teenagers in Beirut from dietary exposure to these mycotoxins. Analytical data on the contamination of raw and processed cereals and cereal-based products, pulses and nuts were collected. The mean levels of AFT, OTA and DON were calculated for each food items. Levels of dietary exposure were obtained by combining food consumption data with the mean mycotoxin levels, adopting a deterministic approach. Intakes were calculated for average and high consumers (75th and 95th percentile) among children and teenagers, and compared with the provisional tolerable daily intake (PTDI) or provisional tolerable weekly intake (PTWI) of the respective mycotoxin. The results showed that mycotoxin levels in the food samples were generally below national/European maximum limits. However, high levels of AFT, OTA and DON were found in some samples of nuts, biscuits and bread. The calculated intake for AFT exceeded its respective PTDI in all groups by a factor ranging from 3 to 7. The intakes of OTA and DON were found to be below the threshold of toxicological concern established for these mycotoxins by international expert groups, although the intake of DON in children at the highest percentile (P95) was close to its PTDI. Our study highlights the need to reconsider the maximum permissible levels of total aflatoxins in some foodstuffs and to establish regulatory guidelines regarding OTA and DON. The results also emphasise the need for routine monitoring of the levels of mycotoxin contamination in foodstuffs that are highly consumed by Lebanese children and teenagers, i.e. cereals and cereal-based products.     

国内外真菌毒素检测方法研究现状及进展

真菌毒素是真菌产生的小分子有毒代谢产物,通常以痕量形式存在于基质中,不表现为急性毒性,但具有蓄积性,长期摄入易引发癌症、突变及畸形,从而对人类安全造成威胁。本文着重介绍了黄曲霉毒素、赭曲霉毒素、伏马菌素、玉米赤霉烯酮及其代谢物、单端孢霉烯族类毒素以及麦角碱等毒性相对较强的真菌毒素的来源、结构和毒性。由于许多真菌毒素结构相似且含量较低,需要采用高选择性、准确、快速定性定量方法,因而本文就目前国内外常用的传统及新型的真菌毒素检测方法进行了概述和比较,主要包括:薄层色谱法,液相色谱法,气相色谱法,免疫化学法,核酸适配体法以及液相色谱-质谱联用技术(LC-MS/MS)在多毒素检测中的应用,拟为真菌毒素的检测研究提供参考。     

Epigenetic regulation of miRNA‐cancer stem cells nexus by nutraceuticals

Nutraceuticals, the bioactive food components represented by many naturally occurring dietary compounds, have been investigated for a few decades for their numerous beneficial effects, including their anticancer properties. The initial interest in the cancer‐preventing/therapeutic ability of these agents was based on their ability to affect multiple signaling pathways that are deregulated in cancer cells. With a shift in the focus of cancer research to the emerging areas such as epigenetic regulation, microRNAs (miRNAs) and the cancer stem cells (CSCs), nutraceuticals initially appeared out of place. However, research investigations over the last several years have slowly but firmly presented evidence that supports a relevance of these agents in modern day research. While nutraceuticals are increasingly being realized to alter miRNA/CSCs expression and function, the molecular mechanism(s) are not very clearly understood. Epigenetic regulation is one mechanism by which these agents exert their anticancer effects. In this focused mini review, we summarize our current understanding of epigenetic regulation of miRNAs and CSCs by nutraceuticals. We discuss both direct and indirect evidences that support such an activity of these compounds.     

Impact of nonthermal food processing techniques on mycotoxins and their producing fungi

Mycotoxins are a significant threat to food safety and quality. Over the years, mycotoxins have been detected in almost all food and feed crops without any regional barrier. Conventional techniques for decontamination of mycotoxin involve physical, chemical, and biological methods, but these technologies often impact the quality of food in terms of changes in nutritional and sensory attributes. We examined the effects of nonthermal techniques on mycotoxins and their producing fungi to remove or reduce mycotoxin levels in food products without compromising food quality. Nonthermal technologies employ different lethal agents (including ozone, cold plasma, light, pressure, radiation, ultrasound, electric field, and magnetic field) to degrade mycotoxins while minimising product thermal exposure. However, the degradation pathway and toxicology of treated products need further research for a better understanding. With such food process development and optimisation efforts, food processors can employ various nonthermal technologies as tools for delivering consumer-desired mycotoxin-free food products with intact nutritional and sensory quality.