Reference on Mycotoxins Occurrence, Prevalence, and Risk Assessment in Food Systems (original) (raw)
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Food Industrial Processes - Methods and Equipment, 2012
The term mycotoxin was used for the first time in 1961 in the aftermath of a veterinary crisis in England, during which thousands of animals died. The disease was linked to a peanut meal, incorporated in the diet, contaminated with a toxin produced by the filamentous fungus Aspergillus flavus (Bennet & Klich, 2003; Richard, 2007). In general, mycotoxins are low-molecular-weight compounds that are synthetized during secondary metabolism by filamentous fungi; their chemical structure may range from simple C4 compounds to complex substances (Paterson & Lima, 2010). Mycotoxins are natural contaminants in raw materials, food and feeds. Mould species that produce mycotoxins are extremely common, and they can grow on a wide range of substrates under a wide range of environmental conditions; they occur in agricultural products all around the world (Bennet & Klich, 2003). Many mycotoxins may be toxic to vertebrates and other animal groups and, in low concentrations, some of them can cause autoimmune illnesses, and have allergenic properties, while others are teratogenic, carcinogenic, and mutagenic (Bennet & Klich, 2003; Council for Agricultural Science and Technology [CAST], 2003). Apparently, mycotoxins have no biochemical significance on fungal growth; they may have developed to provide a defense system against insects, microorganisms, nematodes, animals and humans (Etzel, 2002). Exposure to mycotoxins may occur through ingestion, inhalation, and dermal contact, and it is almost always accidental. Most cases of mycotoxicoses (animals and humans) result from eating contaminated food. Human exposure can be direct via cereals or indirect via animal products (e.g. meat, milk and eggs) (CAST, 2003). Most mycotoxins are relatively heat-stable within the conventional food processing temperature range (80-121°C), therefore so little or no destruction occurs under normal cooking conditions, such as boiling and frying, or even following pasteurization (Milicevic et al., 2010). The stability of mycotoxins during food processing has been reviewed in the work by Bullerman & Bianchini (2007). In general, the application of a food process reduces mycotoxin concentrations significantly, but does not eliminate them completely. The food processes that have been examined include physical treatments (cleaning and milling) and thermal processing (e.g. cooking, baking, frying, roasting and extrusion). The different treatments have various effects on mycotoxins, and those that utilize the highest temperatures have the greatest effects: roasting or cooking at high temperatures (above 150 °C) appear to reduce mycotoxin concentrations significantly (Bullerman & Bianchini, 2007). www.intechopen.com Food Industrial Processes-Methods and Equipment 170 It has been estimated that 25% of the world's crops are affected by fungal growth, and commodities may be, both pre-and post-harvest, contaminated with mycotoxins. The mycotoxins that can be expected in food differ from country to country in relation to the different crops, agronomic practices and climatic conditions (Bryden, 2007). Since climate changes affect the growth of mycotoxigenic fungi, mycotoxin production is also influenced (Magan et al., 2003). Currently, more than 400 mycotoxins are known. Scientific attention has mainly focused on those that have proven to be carcinogenic and/or toxic in humans and animals. Five classes of mycotoxins are considered the most significant in agriculture and in the food industry: aflatoxins (aflatoxin B1), ochratoxins (ochratoxin A), fumonisins (fumonisin B1), zearalenone, and patulin which are derived from polyketide (PK) metabolism, and trichothecenes (deoxynivalenol), whose biosynthetic pathway is of terpenoid origin. PKs are metabolites that are derived from the repetitive condensation of acetate units or other short carboxylic acids, via an enzymatic mechanism that is similar to that responsible for fatty acid synthesis (Huffman et al., 2010). Aflatoxin, ochratoxin, fumonisin, trichothecene, zearalenone and patulin are the most widespread mycotoxins in animal feed and human food. The chemical structure, biosynthetic pathway, mycotoxigenic fungi, the influence of environmental factors and toxicology will be briefly described for each class. Zearalenone will not be dealth with in the present work as, because of its hormonal activity, there is considerable knowledge about ZEA and its derivatives which can be found in the literature on growth hormones. 1.1 Toxigenic fungi Aspergillus, Alternaria, Claviceps, Fusarium, Penicillium and Stachybotrys are the recognized genera of mycotoxigenic fungi (Milicevic et al., 2010; Reddy et al., 2010). Many of these genera are ubiquitous and, in some cases, apparently have a strong ecological link with human food supplies. The natural fungal flora associated with food production is dominated by the Aspergillus, Fusarium and Penicillium genera (Sweeney & Dobson, 1998). Fusarium species are pathogens that are found on cereal crops and other commodities, and they produce mycotoxins before, or immediately after, the harvest. Some species of Aspergillus and Penicillium are also plant pathogens or commensals, but these genera are more commonly associated with commodities and food during drying and storage (Pitt, 2000). Toxigenic moulds are known to produce one or more of these toxic secondary metabolites. However, not all moulds are toxigenic and not all secondary metabolites from moulds are toxic. Many fungi produce several mycotoxins simultaneously, especially Fusarium species. Moreover, recent studies have demonstrated that the necrotrophic pathogens of wheat, Stagonospora nodorum, Pyrenophora tritiirepentis and Alternaria alternata, are also capable of synthesizing an array of mycotoxic compounds during disease development (Solomon, 2011). Nowadays, the identification and quantification of mycotoginenic fungi are carried out by PCR. Diagnostic PCR-based systems are now available for all of the most relevant toxigenic fungi: producers of aflatoxins, trichotecenes, fumonisins and patulin (Niessen, 2007; Paterson, 2006). The primers for mycotoxin pathway sequences have been reviewed in the work by Paterson (2006). 1.2 Influence of environmental factors on mycototoxin production The production of mycotoxins is highly susceptible to temperature, moisture, water activity (a w), pH and oxygen concentration, the same environmental factors that affect the growth of www.intechopen.com Mycotoxins in Food 171 toxygenic fungi. Moisture and temperature are two factors that have a crucial effect on fungal proliferation and toxin biosynthesis (Bryden, 2007; Paterson & Lima, 2010). The incidence and level of mycotoxin contamination are closely related to the geographic position and to seasonal factors as well as to the cultivation, harvesting, stocking, and transport conditions (Milicevic et al., 2010). Mycotoxin contaminations can be divided into the one that occurs in the developing crop (preharvest) and the one that develops after maturation (post-harvest). In the pre-harvest period, preventive measures are included in good agronomic practices, such as the careful use of insecticides and fungicides, irrigation to avoid moisture stress, harvesting at maturity and improvement by genetic resistance to fungal attack. During the post-harvest period, the control of the moisture and temperature of the stored commodity will largely determine the degree of fungal activity and consequently the mycotoxin synthesis (Bryden, 2007). Treatments with chemicals, including sodium bisulfite, ozone, and ammonia, acids and bases, represent an opportunity to control fungal growth and mycotoxin biosynthesis in stored grains (Bozoglu, 2009; Magan, 2006; Magan & Aldred, 2007). In recent years, a good control of mycotoxigenic fungi has been achieved using plant products (e.g. extracts and essential oils) as environmental friendly fungicides (Nguefacka et al., 2004; Reddy et al., 2010; Thembo et al., 2010). Moreover, biological control represents a new opportunity in control strategies: there is evidence that Bacillus sp., propionic acid bacteria and lactic acid bacteria (LAB) are able to inhibit fungal growth and mycotoxin production (Bianchini & Bullerman, 2010). 1.3 Toxicology and health Mycotoxins are toxic to vertebrates and humans at low concentrations. Mycotoxicoses in humans or animals have been characterized as food or feed related, non-contagious, nontransferable, and non-infectious (Zain, 2011). Mycotoxins have various acute and chronic effects on humans and animals, depending on the species. Within a given species, the impact of mycotoxins on health is influenced by age, sex, weight, diet, exposure to infectious agents, and the presence of other mycotoxins (synergistic effects) and pharmacologically active substances (Milicevic et al., 2010; Zain, 2011). The majority of mycotoxins currently known are grouped, according to their toxic activity, under chronic conditions as mutagenic, carcinogenic or teratogenic. Grouping according to their site of action results in hemo-, hepato-, nephron-, dermato-, neuro-or immunotoxins (Niessen, 2007). The most important mycotoxins worldwide are aflatoxins, fumonisins, ochratoxins, deoxinyvalenol and zearalenone. Carcinogenic properties have been recognized with regard to aflatoxin and fumonisins (Mazzoni et al., 2011; Wogan, 1992). Aflatoxin B1 (AFB1) has been linked to human primary liver cancer, in which it acts synergistically with HBV infection and it has been classified as a carcinogen in humans (Group 1 carcinogen). Fumonisin B1, the most abundant of the numerous fumonisin analogues, was classified as a Group 2B carcinogen (possibly carcinogenic to humans) (Zain, 2011; Wild & Gong, 2010). The potential role of dietary factors to counteract the toxic effects of mycotoxins has been reviewed by Galvano et al. (2001): the effect of antioxidants, food components and additives on reducing toxicity, by...
The occurrence of mycotoxins in feed and food
2017
Mycotoxins are secondary fungal metabolites, toxic to humans and animals. Toxigenic fungi often grow on edible plants, thereby contaminating food and feed. The most common mycotoxins are produced by the genera Fusarium, Aspergillus and Penicillium. While Fusarium species are plant pathogens producing mycotoxins (trichothecenes, fumonisins and zearalenone), before or after harvest, species of the genera Aspergillus and Penicillium are frequent contaminants of food during processing and storage. The most toxic mycotoxins produced by the genera Penicillium and Aspergillus are aflatoxins and ochratoxin A. Their occurrence is not only associated with plant commodities, but they are also found in products of animal origin. Plants, as living organisms, can alter the chemical structure of mycotoxins as part of their defence against xenobiotics. The extractable conjugated or non-extractable bound mycotoxins formed remain present in the plant tissue, but are currently neither routinely screen...
Occurrence and Toxicity of Mycotoxins from Food and Feed Resources
Sarhad Journal of Agriculture
G lobal food industry is facing serious challenges due to climate change, different plant diseases, water shortage and poor harvesting practices. Fungi are the larger contributor in incidence of different crops infections. Food and agricultural products contaminated by toxigenic molds (fungi) is a major global food security issue. Every year agro-industrial sector faces huge economic losses in billions of dollars due to fungal contamination of different crops. Improper handling, storage and poor harvesting strategies play its role in fungal infection which ultimately leads to mycotoxin contamination. Mycotoxins are secondary metabolites produced by different filamentous fungi (Bennett, 1987; Tola and Kebede, 2016). They are heterogeneous compounds of low molecular weight. Their notorious reputation is due to their ability to Abstract | Mycotoxins are the secondary metabolites produced by different filamentous fungi. The significance of these low molecular weight compounds lies in the fact that they are the contributors of severe health issues in livestock and humans. Every year mycotoxins infect different crops and animal feedstock by accumulating in the food and feed crops in the field and during transportation, which leads to the huge economic losses. Presently about 300 types of mycotoxins have been identified, while, aflatoxins, fuminisons, ochratoxins, trichothecenes and zearalenone are the major mycotoxins infecting food and feed crops. Consumption of food contaminated with these mycotoxins can cause severe toxicity in human and animals. Members of these fungal genera Fusarium spp., Penicillium spp., and Aspergillus spp., are major mycotoxins producers in food and feed crops. Mycotoxins thrive in high-temperature, humid environments, and they can enter the food chain either directly or indirectly by contaminating food and feed crops. They can cause infection before and after agricultural crop harvesting. Economically mycotoxins infection leads to loss of feedstock, reduced livestock production, human and animal life threatening diseases and major issues leading to global food security. All these factors demand for extensive research for early mycotoxins detection methods and making regularity bodies to contain the spread of mycotoxins. This review summarizes the occurrence and toxicity of five major types of mycotoxins associated with food and feed and their importance in human nutrition and animal health.
Toxins, 2010
Mycotoxins are toxic compounds, produced by the secondary metabolism of toxigenic moulds in the Aspergillus, Alternaria, Claviceps, Fusarium, Penicillium and Stachybotrys genera occurring in food and feed commodities both pre- and post-harvest. Adverse human health effects from the consumption of mycotoxins have occurred for many centuries. When ingested, mycotoxins may cause a mycotoxicosis which can result in an acute or chronic disease episode. Chronic conditions have a much greater impact, numerically, on human health in general, and induce diverse and powerful toxic effects in test systems: some are carcinogenic, mutagenic, teratogenic, estrogenic, hemorrhagic, immunotoxic, nephrotoxic, hepatotoxic, dermotoxic and neurotoxic. Although mycotoxin contamination of agricultural products still occurs in the developed world, the application of modern agricultural practices and the presence of a legislatively regulated food processing and marketing system have greatly reduced mycotoxi...
Mycotoxins: A Threat to Food Security and Health
This is an open access article & it is licensed under a Creative Commons Attribution Non-Commercial 4.0 International (https://creativecommons.org/licenses/by-nc/4.0/) Multicellular filamentous fungi grown on the surface and inside of moist food secretes toxins in the form of their secondary metabolites which are commonly called mycotoxins. The presence of mycotoxins in food has been a burning issue and a threat to food security and safety. The global population has skyrocketed and continues to be, which has created a challenge of providing quality food to the consumers. Aflatoxins, prevalent in most of the food crops in Nepal as well have posed a risk to national food security. Moreover, the consumption of food products containing mycotoxins is a cause of several health hazards like cancer, gastrointestinal problems, and neuropsychiatric effects. Mycotoxins not only has affected humans but also animals. Prevention, decontamination, and inhibition of absorption of toxins have been done to manage and mitigate the effects of mycotoxins. Recent research on mycotoxins is focused on the development of new methods to detect and analyse masked mycotoxins obtained from various sources. This review shows the contribution of mycotoxin in the global food security issue as well as its deleterious effects on human and animal health.
An overview of mycotoxin contamination in foods and its implications for human health
Toxin Reviews, 2010
Mycotoxins are natural contaminants of cereals and other food commodities throughout the world and they significantly impact human and animal health. Mycotoxins are toxic secondary metabolites produced by species of filamentous fungi growing on grains before harvest and in storage. When ingested, inhaled, or absorbed through skin, mycotoxins may reduce appetite and general performance, and cause sickness or death in humans. Mycotoxins subject to government regulation in most countries include aflatoxins, fumonisins, ochratoxins, deoxynivalenol, zearalenone, and patulin, produced by species of Aspergillus, Fusarium, and Penicillium. Aflatoxins, fumonisins, and ochratoxins pose the most serious threats to human health worldwide. This review describes the prevalence of mycotoxins in foods and its implications on human health, which may help in establishing and carrying out proper management strategies. Data from detailed investigations of food mycotoxins worldwide help provide safer food for consumption and help prioritize future research programs.
Mycotoxins: food safety management implications
Quality Assurance and Safety of Crops & Foods, 2009
Food chemical contaminants are chemicals that are not normally found in a particular food, their ingredients or the original raw material. Their presence is only acceptable when the levels that they occur at do not compromise public safety and are unavoidable after exercise of best practice. Mycotoxins, the toxic metabolites of certain filamentous fungi, are one group of contaminants and specific legislation, regulating permitted levels of contamination exists for a number of mycotoxin/food combinations. In many cases there is now considerable knowledge not only of the conditions conducive to their formation but also of the mechanisms that need to be in place to prevent or limit their occurrence. In a number of cases this knowledge has been converted into guidelines or other strategies, which both farmers and the food industry have adopted. Assessing levels of compliance and efficacy of these measures is achieved through appropriate audit/inspection and chemical-analytical regimes.
Mycotoxins in the food chain: contamination of foods of animal origin
Food safety assurance and veterinary public health, 2019
The recognition and control of mycotoxin-related risks have improved markedly since the first recognized mycotoxin poisoning outbreaks in the late 1960's. However, mycotoxins remain a major public health concern, as mycotoxins occur throughout the agricultural regions of the world, with varying distribution patterns and concentrations over space and time. The dynamic nature of mycotoxin occurrence requires constant vigilance. Mycotoxins, produced by fungi that grow in plant materials used to produce animal feeds, represent a major risk to animal health, welfare and productivity, and are of public health concern, particularly in the case of aflatoxin contamination of milk. Other mycotoxins and their metabolites, including ochratoxin A, fumonisins, trichothecenes and zearalenone, may contaminate foods of animal origin to some extent, but at a low level, and the associated risks are considered to be minor in comparison to the direct exposure of consumers form other (plant-derived) food commodities.
Mycotoxins in food – how to prevent and what to do when things go bad
E3S Web of Conferences
Mycotoxins are secondary metabolites of microscopic moulds with pronounced toxic properties. Moulds infect products of plant and animal origin at any stage of their receipt, transportation and storage, in industrial and home conditions. Mycotoxins are more commonly found in plant foods. Their biosynthesis by fungi occurs during the ripening and harvesting period under unfavourable meteorological conditions and improper grain storage. Untimely harvesting or insufficient drying of the crop before storage, storage and transportation of products with insufficient protection against moisture leads to the multiplication of microorganisms and the formation of toxic substances in food products.
Mycotoxin contamination of commercially important agricultural commodities
Toxin Reviews, 2009
Mycotoxins are toxic secondary metabolites produced by species of filamentous fungi growing on seeds before harvest or in storage. Mycotoxin contamination of agricultural commodities is a serious concern for human and animal health. The mycotoxins subject to government regulation are aflatoxins, fumonisins, ochratoxins, cyclopiazonic acid, deoxynivalenol/nivalenol, patulin, and zearalenone, which are produced by species of Aspergillus, Fusarium, and Penicillium, with aflatoxins and fumonisins arguably posing the greatest threat to human health worldwide. The frequency, magnitude, and causes of mycotoxin contamination of important agricultural commodities are reviewed here, as a first step in prioritizing mycotoxin problems for future research.