Name of some important mycotoxin-producing fungi, susceptible foods, and mycotoxin effects on humans and animals .
Mycotoxins are secondary metabolites synthesized by a variety of fungal species such as Aspergillus, Penicillium, Fusarium, and Alternaria. These secondary metabolites are toxic and have a significant impact if they enter the production and food chain. Mycotoxins have attracted worldwide attention because of their impact on human health, huge economic losses, and domestic and foreign trade. Although more than 400 mycotoxins have been identified, most studies have focused on aflatoxins (AF), ochratoxin A (OTA), Fusarium toxins, fumonisin (FUM), zearalenone (ZEA), trichothecenes (TCT), and deoxynivalenol/nivalenol due to food safety and economic losses. This chapter will be addressing the type of mycotoxins, its importance in food industry, preventive measures, and implementation of hazard analysis critical control point (HACCP) to control mycotoxin.
- ochratoxin A
- Fusarium toxins
- food industry
Mycotoxins are secondary toxic metabolites with a wide variety of chemical structures synthesized by fungi (mold) . Mycotoxins are thought to be a kind of “chemical defense system” to protect mold from insects, microorganisms, nematodes, grazing animals, and humans . Molds reproduce by means of spores, and their small molecular weight spores are easily disseminated to environment by wind. They cannot be affected by the adverse environmental conditions and can be present in the latent state for long periods. Moreover, when the environmental conditions are appropriate, spores return to vegetative form and can form into new mold colonies. Agricultural products can be contaminated with mold in pre-harvest via insect and bird damage and harsh weather condition damage such as hail damage. In addition, selected harvesting method is one of the most important reasons in contamination of the mold to the products. Improper storage, transport, and marketing can also cause the mold growth and synthesis of mycotoxins .
Mycotoxin can occur in food and agricultural products via many contamination pathways, at any stage of production, processing, transport, and storage (Figure 1) . Factors that affect mold growth and mycotoxin production are temperature, relative humidity, fungicides and/or fertilizers, interaction between the colonizing toxigenic fungal species, type of subtract and nutritional factors, geographical location, genetic requirements, and insect infestation [5, 6].
Approximately 400 fungal secondary metabolites are known to be toxic, and one quarter of agricultural products have been reported to be contaminated with mycotoxins in the world [5, 6, 7, 8, 9]. While a type of mold may form more than one mycotoxin, a mycotoxin can be synthesized by many molds. The most common types of mold which are known to produce mycotoxins are
According to the result of many studies in poultry and mammals, mycotoxins can be carcinogenic, mutagenic, teratogenic, hepatotoxic, nephrotoxic, immunosuppressive, and embryotoxic . The phenomenon of toxicity is called mycotoxicosis occurring after consumption of mycotoxin-contaminated product by human and animal .
Especially cereals, grains, nuts, oilseeds, fruits, dried fruits, vegetables, cocoa and coffee beans, wine, beer, herbs, and spices are major mycotoxin vectors since they are consumed by a large mass of people and animals . Mycotoxins cause different degrees of toxicity according to exposure time, mycotoxin amount, physiological state, and sensitivity of the organism in humans and animals.
In addition to risk of public health, mycotoxins generate high level of economical loses for food industry due to reduced crop yields, lost trade revenues (local and international), and livestock illnesses [13, 14]. Elimination of mycotoxin is quite though due to resistant to physical, chemical, and biological methods; however, some of the measures described in the following sections may help to prevent mycotoxin. The methods used for mycotoxin determination are chromatography such as high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), gas chromatography-mass spectrometry (GC-MS), and also enzyme-linked immunosorbent assay (ELISA) technique and biosensor-based screening methods . Detection is complicated due to limitations in analytical methodology . Therefore, prevention of mold contamination and mycotoxin synthesis is essential for food safety in food industry.
According to the Food and Agricultural Organization (FAO), 77 countries have established guidance and regulations on mycotoxin in food and feed to control the level of mycotoxin. On the other hand, 13 countries including African countries still do not have specific regulation for food safety .
2. Importance of mycotoxin in food industry
Ergotism is one of the oldest determined mycotoxicoses (disease) in human and results from consumption of the ergot body in rye or other grains infected by a parasitic fungus of the genus
Mycotoxins can occur in the food in several ways (Figure 1), but technically divided into two groups; first is mold growth as a pathogen plant in field, another one is grow on stored. After plant materials are contaminated with mold spores from soil and air, they easily contaminate other food source, production area, laboratory, and even kitchen of our homes. Certain species of mold are capable of mycotoxin synthesis; therefore, each food contaminated with mold always may not contain mycotoxins. Nevertheless, moldy products are considered to be risky products in terms of mycotoxin.
Mycotoxins appear in almost all kinds of animal feed and products such as wheat bran, noug cake, pea hulls, maize grain, milk and meat, and also human food such as cereal, fruit and vegetables, spice, etc. . Consuming these foods creates serious health risks in human and all animal species. Mycotoxin intake by feed or food causes chronic intoxication rather than acute symptoms. Acute toxicity is observed in high-dose mycotoxin exposure, and symptoms show a rapid effect such as borborygmy, abdominal pain, diarrhea, etc. On the other hand, low-level mycotoxin exposure in long period causes serious impairments in the liver, kidney, and immune system organs and tissues. Therefore, mycotoxin plays a significant role in cancer in these organs . Some important mycotoxin health effects are shown in Figure 2. Toxic effects on humans and animals of important mycotoxins are shown in Table 1 .
|Mycotoxins||Genus/species||Major food||Toxic effects and diseases|
|Aflatoxin||Cereals, feeds, oilseeds and pulp, coconut||Carcinogenic, hepatotoxicity, teratogenicity, decreasing immune systems, affecting the structure of DNA, hepatitis, bleeding, kidney lesions|
|Fumonisin||Cereals, corn||Encephalomalacia, pulmonary edema, carcinogenic, neurotoxicity, liver damage, heart failure, esophageal cancer in humans|
|Cereals, herbs, oil seeds, figs, beef jerky, fruits, and wine||Kidney and liver damage, loss of appetite, nausea, vomiting, suppression of immune system, carcinogenic|
|Patulin||Silage, wheat, feeds, apples, grapes, peaches, pears, apricots, olives, cereals||Neural syndromes, brain hemorrhage, skin lesions, skin cancer, lung, mutagenicity, antibacterial effect|
(T2, DON, DAS, HT2)
|Cereals, feeds, silage, legumes, fruits, and vegetables||Immune suppression,|
skin necrosis, hemorrhage, anemia, granulocytopenia, oral epithelial lesions, GIS lesions, hematopoietic, alimentary toxic aleukia (ATA), hypotension, coagulopathy
|Zearalenone||Cereals, corn, silage, timothy grass, fodder||Carcinogenic, hormonal imbalance estrogenic effect, reproductive problems, teratogenic|
Mycotoxins have caused many serious outbreaks worldwide. There was an outbreak that occurred in 1967, and 26 people were poisoned because of the consumption of moldy rice for up to 3 weeks in Taiwan . An outbreak of aflatoxicosis affecting humans, reported in India, led to the death of 100 people in 1974 . Another outbreak was reported in India in 1995, affecting 1424 people due to sorghum and maize contaminated with fumonisin . During January–June 2004, an aflatoxicosis outbreak in eastern Kenya resulted in 317 cases and 125 deaths .
Mycotoxin contamination in foods and fodder has been becoming a global concern day by day. According to Food and Agricultural Organization (FAO) reports, it is estimated that mycotoxin affects nearly 25% of the world’s crop each year and is causing huge agricultural product and industrial losses in billions of dollars . For example, estimated annual loss in the United States is approximately $ 0.5–1.5 billion . The main effects of mycotoxins on national economies can be thought in five ways:
Product yield losses due to toxigenic mold diseases
Decrease in commercial value because of contaminated food and feed
Human and animal health losses due to harmful impacts associated with mycotoxin-contaminated food and fodder consumption
Cost of analysis of mycotoxin
Strategies to control mycotoxin contamination
Economic impacts are felt by agricultural chain such as manufacturer of plant and animal, especially cereal industry, consumers, and briefly all farm-to-fork steps.
3. Worldwide important mycotoxin in food industry
3.1 Aflatoxins (AF)
Aflatoxins are a group of toxic secondary metabolites of filamentous fungi,
3.2 Ochratoxin A
Ochratoxin A (OTA) is a natural mycotoxin produced mainly by fungal type of
Fumonisins are generated by various fungal species such as
The International Agency for Research on Cancer (IARC) identified FB1 as possibly carcinogenic to humans (group 2B). Recent studies reported that FB1 causes an increased prevalence of esophageal and liver cancer in humans . Furthermore, this mycotoxin has been found to have toxic effects against several organs (nervous and cardiovascular systems, liver, lung, kidney) in animals . Fumonisins are largely found in corn and corn-based foods and also FB1 in rice, beer, sorghum, cowpea seeds, triticale, beans, asparagus, and soybeans .
3.3.2 Zearalenone (ZEA)
Zearalenone (ZEA), known as an estrogenic mycotoxin, is a secondary metabolite produced by
Several in vivo studies found that ZEA disrupts hormonal balance due to its similarity to naturally occurring estrogens . The mycotoxin has high affinity for estrogen receptors, causing reproduction and fertility disorders in mammals . In addition, it is known that progressive exposure to endocrine-modulatory compound has been linked with carcinogenesis in human . According to the European Food Safety Authority (EFSA) report in 2014, the bioavailability of toxin is up to 80% in human and animals such as rats, rabbits, and pigs . Moreover, recent works report ZEA is metabolized in the liver and has shown hepatotoxic, immunotoxic, carcinogenic, and nephrotoxic effect in animal tests [67, 68, 69]. As this mycotoxin possesses such consumer health risks, the European Union (EU) has prescribed the limits of ZEA (20–350 μg/kg) for various processed and unprocessed cereals .
3.3.3 Trichothecenes (TCT)
Trichothecenes are a large group of mycotoxins produced predominantly by
The mechanism of action of trichothecenes is based on the inhibition of protein synthesis in eukaryotes. This mycotoxin affects peptidyl transferase enzyme binding the 60S ribosomal subunit, thus causing the inhibition of protein translation and ribotoxic stress . Also, Pestka reported these groups of mycotoxins cause immunosuppression or immune stimulation by affecting the leucocytes .
The family of trichothecenes has a significant impact on cereal and grain production due to health risk for human consumption, livestock feed, or malting purposes [77, 78]. According to report from the FDA, economic losses associated with mycotoxin ranges from USD 0.5 million to over USD 1.5 billion from aflatoxin (corn and peanuts), fumonisin (corn), and deoxynivalenol (wheat) in the United States. . Hence, control of these mycotoxins is essential for human and animal health and economic reasons.
Deoxynivalenol (DON), known as vomitoxin, is the most commonly detected trichothecenes in grains such as wheat, barley, oats, rye, and corn and less often in rice, sorghum, and triticale . Even though NIV presence of cereals appears generally to be lower than DON , it has been reported that the occurrence of NIV in of wheat and barley is as prevalent as that of deoxynivalenol (DON) in Japan . According to animal toxicity studies, NIV shows higher toxicity than DON. The LD50 values for DON and NIV in tests in mice were 78 and 39 mg/kg, respectively, and DON and NIV, similarly to other trichothecenes, show inhibitor effect on cell metabolism such as protein, DNA, and RNA synthesis . In addition, these mycotoxins affect cell division and mitochondrial functions [83, 84, 70]. Both mycotoxins exhibit major symptoms such as abdominal discomfort, diarrhea, vomiting, and inflammation of the throat, weight loss, and anorexia .
The World Health Organization (WHO) reported that trichothecenes shows fatal and chronic intoxications on human and livestock and also DON shows teratogenic, neurotoxigenic, and immunosuppressant effects .
According to the conducted BIOMIN World Mycotoxin Survey, DON appeared in 81% of livestock feed from 81 countries worldwide followed by fumonisins that were detected in 71% of samples. Therefore, DON is reported as the most common mycotoxin worldwide (https://www.biomin.net/en/biomin-mycotoxin-survey/).
4. Management of mycotoxin prevention
Food safety is a key component in public health issue, and a mycotoxin is a huge food safety risk in developing countries. Prevention is the most important and effective way in reducing fungal growth and mycotoxin production to ensure food safety. The following steps that explain prevention and control of mycotoxin occurrence include good agricultural practices (GAP) in field, control practices of harvesting and storage, physical methods (cleaning, milling, etc.), implementation of biotechnological application, biological control through the use of controlled atmosphere during storage, detoxification/degradation, and fermentation techniques.
Pre-harvesting is considered first and one of the most important stages to prevent mold growth and mycotoxin synthesis. Several strategies are available for the produce of healthy products and reduce the mold formation at pre-harvesting, including selection of plants according to the soil structure and production capacity, use of plant which is resistant to fungi and insects, irrigation time, make fertilization, use of insecticides to prevent insect damage .
Harvesting at the appropriate time periods (low moisture and full maturity) is essential for reducing the risk of a mycotoxin contamination since overmaturity creates sensitivity to mold growth. Additionally, suitable harvesting equipment and procedures should be used, and crops should be dried after maturity to both reduce grain moisture to safe levels .
The latest technological advances provided new paths in mycotoxin control strategies that include the use of a controlled atmosphere with inhibitory or a protective effect and use of naturally occurring compounds under different conditions and essential oils with antioxidant properties to decrease fungal growth and mycotoxin production in grains during storage . Moreover, these strategies also include using regularly cleaned transport vehicles to prevent cross contamination of products; monitoring of temperature, humidity, aeration and pest infestation periodic during storage ; using mold inhibitors (propionic acid) to contaminated food and feed; and application of disinfectant such as sodium hypochlorite to storage area .
Some studies have shown that using physical methods (dehulling, washing, sorting, and cleaning of visible moldy seed) reduces different mycotoxin species in foods regardless of grain genre . Scudamore and Pascale et al.  and Patel  observed a reduction of T-2 (62%) and HT-2 (53%) and DON (50%) in wheat seeds after cleaning. Scudamore and Patel also reported a 32% reduction in fumonisin levels in corn in an industrial enterprise . Moreover, milling is an important effect in the reduction of
One of the best applicable strategies for the prevention of mycotoxin formation is the cultivation of fungal infestation-resistant plants and improvement of the genetic composition to suppress mycotoxin production . The benefits of biotechnological applications were observed with Aflasafe. Aflasafe is a biocontrol product that includes a blend of four fungal species covered over grains which reduce aflatoxigenic fungi that produce AFs in maize and groundnuts (https://aflasafe.com/).
Mycotoxins are resistant to heat and cannot be completely destroyed under normal cooking process. On the other hand, mycotoxin reduction has been determined after heating, and this may be the result of reactions changing the chemical structure . Ryu et al. reported heat treatment (at temperature 120–160°C) causes a reduction between 66 and 83% of ZEN . Scott and Lawrence also reported a reduction of 60–100% of fumonisins with a heat treatment at 190°C (60 min) and 220°C (25 min).
Biological control of mycotoxins via detoxification/degradation offers a promising alternative method . Recently the effectiveness of fermentation for the reduction and elimination of mycotoxins has also been proven. Studies documented in the literature generally show that mycotoxins are reduced by conversion, detoxification, binding, degradation, and decontamination after food fermentation . Modification of the chemical structure of the mycotoxin molecule, removal or detoxification/inactivation, and adhesion to bacterial cell walls provide a reduced toxicity during fermentation . Implementation of these preventive methods cannot solve the problem alone; also it must be an integral part of an integrated food safety management system based on the hazard analysis and critical control point (HACCP).
5. Implementation of HACCP to mycotoxin control
HACCP is a food management system where food safety is addressed through the analysis, control, and monitoring of physical, chemical, and biological hazards from raw material manufacturing, supply, and handling to production, distribution, and consumption of the finished product . The National Advisory Committee on Microbiological Criteria for Foods (NACMCF) published a guideline about HACCP containing seven basic principles, decision tree, and all plans in 1992 . Implementation of HACCP is an effective strategy for prevention, control, and periodic monitoring of mycotoxin in all stages from field to the consumer. There are 12 successive steps recommended to implementation of HACCP system. Previous HACCP studies can be researched to set up tasks from 1 to 5 that specify each food process, and tasks required for mycotoxin control begin at 6 (Principle 1).
Establish the HACCP team.
Describe the product.
Identify the product’s intended use.
Draw up the commodity flow diagram.
Confirm the flow diagram on-site.
Identify and analyze hazard(s) (Principle 1).
Determine the critical control points (CCPs) (Principle 2).
Establish critical limits for each (CCP) (Principle 3).
Establish a monitoring procedure (Principle 4).
Establish corrective action (Principle 5).
Verify the HACCP plan (Principle 6).
Keep record (Principle 7).
|Crops and tolerated levels of mycotoxins (μgkg−1)|
|The United States||Total AF|
Microbiological and/or chemical tests can be used to confirm which product is meeting CCP.
Asking questions especially to CCP employees.
Internal or external audit by independent person to check whether HACCP system is being implemented.
|Step/CCP||Hazard analysis||Monitoring||Corrective action|
|Pre-harvest/ growing||Low soil moisture leading to plant stress during kernel development||Irrigate||Lower limit of critical water activity (aw) (check with your agronomist/extension staff for an exact value)||Measure soil moisture and record||Weekly on Monday morning||Additional irrigation; record amounts|
|Insufficient soil nutrients leading to plant stress during kernel development||Fertilize||N, P, and K applications as recommended for hybrid by local agronomists (insert the values)||Fertilizer applied (appropriate for soil type and hybrid); amounts and type recorded||As recommended for hybrid||Additional fertilizer; record amounts added|
|Insect attack leading to damaged kernels||Integrated pest management (IPM) plan||Insect population within acceptable limits as determined by control program||Visual inspection and sample, with results recorded||Weekly||Apply pesticide in accordance with IPM plan|
|Harvest||Damage to kernels from harvester||Harvest when kernels are dry||Moisture content ≤14%||Measure and record grain moisture||Prior to harvest||Delay harvest till kernels are dried enough|
|Storage||Excessive moisture content of kernels||Do not store until kernels are dry||Moisture content ≤14%||Measure and record grain moisture||Immediately prior to storage||Dry mechanically|
|Insect attack, allowing fungi to penetrate kernels||IPM plan||No evidence of insect or rodent infestation using inspection protocols specified in IPM plan||Visual inspection with results recorded||Weekly||Apply pest control methods in accordance with IPM plan|
|High ambient humidity and temperature||Aerate grain to control temperature and humidity||Temperature and humidity within limits recommended in industry literature||Measure and record humidity, ambient temperature, and airflow||Daily during storage||Adjust aeration time of day or airflow to achieve desired temperature and humidity|
Mycotoxin is a well-known food safety risk, which is a threat to human and livestock health, and has high economic significance in food industry. Recently, the food industry has become aware of the new term modified mycotoxins introduced by Rychlik et al. (masked mycotoxin) . Food safety risk has risen since masked mycotoxins which pose many difficulties including the unknown occurrence/co-occurrence of these compounds and their toxicological properties. In addition, Lorenz et al. reported that the European Food Safety Authority (EFSA) has taken into account efforts to address this emerging issue in food safety by developing strategies on how to evaluate potential added health risk due to the occurrence of modified mycotoxins .
Mycotoxigenic molds are difficult to prevent and control due to their widespread presence in nature. Prevention of mycotoxin synthesis in all stages of food processing is an essential point for public health and economic reasons. Many practices used for prevention of mycotoxin include good agricultural practices (GAP) in field, control practices of harvesting and storage, physical methods (cleaning, milling, etc.), implementation of biotechnological application, biological control through the use of controlled atmosphere during storage, detoxification/degradation, and fermentation techniques.
Meanwhile a number of techniques for mycotoxin control and management prove to be quite costly and/or unenforceable in some cases. On the other hand, using fermentation process for appropriate process has been recommended for mycotoxin reduction by Adebiyi et al. . In the future, more emphasis should be given to nanotechnology and genetic engineering practices in the development of durable product types to ensure food safety.
In addition to these applications, food safety management systems such as HACCP, GAP, and good manufacturing practices (GMP) should be integrated at all stages of production, transport, and storage, in order to minimize contamination in food industry. Also fairly new food safety system including threat assessment critical control points (TACCP), vulnerability critical control points (VACCP), and hazard analysis and risk-based preventive controls (HARPC) should be investigated and implemented to ensure an effective control system.