Mycotoxins

October 2018

Mycotoxins occur widely in nature and are produced by filamentous fungi. Organisms producing them can develop in foods at any stage in the food chain. They may be present in food as a result of the organism growing and producing the toxin or they enter the food chain by a more indirect route, for example, in milk from animals that have consumed contaminated feed.

Effective control requires a combination of good agricultural practice, carefully controlled storage conditions and surveillance at every stage from farm to fork. Developing economies are at particular risk of contamination as moist, warm climatic conditions favour mould growth, while adequate control and good storage may be difficult to achieve.  

Introduction

Mycotoxins are naturally occurring toxins produced by filamentous fungi in many agricultural crops but especially in cereals and most oilseeds both in the field, after harvest, during storage, and later when processed into food, animal feed, and feed concentrates  Mycotoxins occur particularly in regions or countries with climates of high temperature and humidity or where there are poor crop harvesting and storage conditions, which encourage mould growth and mycotoxin development.  Human intake of mycotoxins occurs mainly from plant-based foods and from animal-derived foods such as milk and milk products and certain fermented meat-based products.  Mycotoxicosis is poisoning associated with exposures to mycotoxins and the symptoms depend on the type of mycotoxin, the concentration and length of exposure as well as age, health, and gender of the exposed individual. There is little published information on synergistic effects associated with other factors such as genetics, diet, and interactions with other toxins.

Human reactions to mycotoxins have been recorded for many centuries and the most significant is the disease known as ergotism. In this disease of rye, the fungus Claviceps purpurea grows in the developing seed and eventually replaces it with a hard fungal biomass.  When the rye seeds were harvested and ground into flour, the ergot was also ground up releasing a Pandora’s box of deadly poisons i.e. ergotamine (a vascoconstrictor); ergonovine (cause of spontaneous abortion); ergine and lysergic acid hydroxyethylamide  (causing convulsion).  In Europe in the Middle Ages, rye was the staple diet of the peasantry and records show that there were massive outbreaks of convulsive ergotism in the 9th and 16th centuries, and later, with huge levels of suffering. Thus while for many centuries rye was the staple food, it was not only “the staff of life” but also “the sceptre of death”.  It is accepted by most medical historians that throughout the Middle Ages in Europe, the ergot mycotoxins exerted a major role in restricting population expansion and only the reduced dependency on rye cereal as the staple food in the 16th and 17th centuries, with the introduction of wheat and potatoes, allowed the steady upward movement in population growth. Other more recent large-scale outbreaks of human mycotoxicoses, involving different mycotoxins have occurred in South East Asia, India, China, Russia, and Africa, but in all of these outbreaks, including ergotism, there has been strong correlation with the consumption of heavily contaminated food sources.

While over 300 mycotoxins have been identified, about 20 have been shown to occur naturally in foods and feeds at significant levels and frequency to be of a food safety concern. The majority of these toxins are produced by fungi of the genera, Aspergillus, Penicillium, and Fusarium.  The most commonly occurring mycotoxins are aflatoxins (B1, B2, G1, G2, M1), ochratoxin A, patulin, citrinin, sterigmatocystin, and the fusarium toxins namely fumonisins (B1, B2 and B3), T-2 and HT-2 toxins, zearalenone, nivalenol, and deoxynivalenol (Table 1).

Table 1. Some important toxigenic species of filamentous fungi and related mycotoxins

Fungal species

Toxin(s) produced

Aspergillus flavus

Aflatoxins B1 (AFB1) B2,(AFB2) (AFM1, hydroxylated metabolite of AFB1), cyclopiazonic acid

A. parasiticus

Aflatoxins B1, (AFB1) B2,(AFB2), G1(AFG1) G(AFG2

A. ochraceus

Ochratoxin A; Penicillic acid

A. versicolor; A. nidulans

Sterigmatocystin, cyclopiazonic acid

Penicillium verrucosum

Ochratoxin A, citrinin

P. purpurogenum

Rubratoxins

P. expansum

Patulin, citrinin

Fusarium sporotrichiodes; F. poae

Trichothecenes A: T-2, HT-2 toxins

F. graminearum

Trichothecenes B: Deoxynivalenol, nivalenol, zearalenone

F. verticilloides; F. proliferatum

Fumonisin B1 both can produce series B and C analogues.

Alternaria alternate

Tenuazonic acid

Stachybotrys chatarum

Satratoxins

Aflatoxin is the most regulated of all the mycotoxins regulated worldwide. Aflatoxin B1 in food and feed, is metabolised to AFM1 in milk in ruminants and in human breast milk. Mycotoxins are, in general, low molecular weight, non-antigenic fungal secondary metabolites formed through several metabolic pathways, e.g. the polyketide route (aflatoxins), the terpene route (trichothecenes), the amino acid route (aflatoxin), and the tricarboxylic acid route (rubratoxin).  Sterigmatocystin and o-methyl sterigmatocystin are, respectively, the penultimate and ultimate precursors of aflatoxins. Although these precursors are chemically and structurally very similar to aflatoxins, their accumulation differs at the species level for Aspergilli. Aspergillus versicolor and A. nidulans produce sterigmatocystin but do not possess the enzymes necessary for the conversion of the toxin into aflatoxin (JECFA, 2016). Some mycotoxins are formed from a combination of two or more principal pathways. Although trichothecene mycotoxins are produced mainly by the genus, Fusarium (Table 1), other species e.g. Trichoderma, Stachybotrys, Trichothecium, can also form these toxins. The trichothecenes are the most chemically diverse of all the mycotoxins.

Mycotoxins enter the human and animal digestive system by direct or indirect contamination of food commodities and animal feed (Table 2).

Table 2. Probable routes for mycotoxin contamination of foods and feeds

 

                            Agricultural products

                                     

  Major sources

 Minor source

Secondary infection

 

Mould damaged/attacked foodstuffs – produce in the field and/or in storage

Cereals; cereal products;

Fruits and fruit products

Consumer food products

Beans and pulses

Vegetables

Compounded animal feeds

Herbs, spices

Tubers

 

Nuts

 

 

Oilseeds

 

 

Mould fermented foods

Cheese

Fermented meat products

Oriental and other fermented products

Fermenter-derived products

Microbial proteins

Food additives

Fermented foods

Animal feed plays an important role in the human food chain because of the implications for the composition and quality of products from livestock such as milk, eggs, and meat. Legislation on animal feed is harmonised at European Union level and applies to feed for farmed livestock; the legislation also covers farmed fish and others including pets and horses. The European Food Safety Authority (EFSA) have carried out risk assessment on a number of mycotoxins (AFB1, deoxynivalenol, zearalenone, ochratoxin A, fumonisins, T-2 and HT-2) that are considered to pose health risks to human and animals.

Mycotoxin contamination of food and feeds is a world-wide problem.  The Food and Agriculture Organisation (FAO) estimated that 25 per cent of the world’s food crops are significantly contaminated with mycotoxins.  Currently, more than 100 countries have regulations regarding levels of mycotoxins in the food and feed industry. Direct economic losses resulting from mycotoxin-contaminated agricultural crops can be measured in reduced crop yields and lower quality, reduced animal performance and reproductive capabilities, and increased disease incidence.  Developed countries are less at risk from mycotoxins than developing countries since they are significantly protected by the high standards of the major food suppliers and retailers, and the regulatory controls which deter the importation of seriously contaminated material. Globalisation of food trade with regard to mycotoxins may have contributed to two major issues in the developing world.  First, stringent mycotoxin standards on exported food crops mean that these countries are likely to export their best-quality foods while keeping contaminated foods domestically, which inadvertently results in higher risk of mycotoxin exposure in those nations.  Second, a large portion of even the best quality foods produced in the developing world for export is rejected for not meeting the stringent standards, resulting in millions of dollars in losses (Wu, 2004; Wu and Gudu, 2012).

Mycotoxicology is a rapidly developing field; thus this, like most Information Statements can at best be a “benchmark”, trying to present the position at a particular point in time.  The EU works toward harmonisation of mycotoxin standards and in the UK, the Food Standards Agency’s (FSA) strategy can be divided into three major themes: (i) maintain current awareness of levels of mycotoxin contamination of foods in general and of UK in particular (UK/FSA, 2003, 2004, 2005a,b,c), (ii) identify factors contributing to the occurrence of mycotoxins and thereby provide information necessary to manage the risk of mycotoxin formation, and (iii) provide stakeholders with advice/tools on how best to manage the problem of mycotoxin contamination.  To enable stakeholders to participate in consultations on mycotoxins and other biologically-derived toxins in foods, a list of interested parties exists.  To fulfil FSA’s strategy, projects on mycotoxins fall into four broad categories:  (i) exposure assessment based on surveys of different mycotoxins in a wide range of foods; (ii) development and improvement of analytical methods; (iii) impact of agronomy and storage – a number of projects have been initiated on the impact of agronomy, the development of tools for good management of the problem, and analytical methods to detect mycotoxigenic fungi early in the toxin synthesis cycle; and (iv) impact on sampling as a key issue in making accurate determinations of mycotoxins.

The European Mycotoxin Awareness Network (EMAN, 2012, 2014) provides high quality scientific information and news about mycotoxins to industry, consumers, legislators, and the scientific community.  Another useful document is the Mycotoxins Factsheet (4th edition) published by the Joint Research Centre of the European Commission (EC, 2011). It gives details and references to the nature of mycotoxins, their occurrence and toxicities, details of useful links to other organizations, as well as having sections on training, proficiency testing, reference materials and methods of analysis.

Modified and masked mycotoxins

Fusarium fungi produce mycotoxins on crops still in the field and the trichothecenes (DON, T-2 toxins), fumonisins and zearalenone are the most important toxins based on occurrence and toxicity. Toxigenic fungi infect a wide range of crops during cultivation and produce mycotoxins which may be present during harvesting, storage and transportation. The parent toxin may be modified by the fungus itself and produce a cocktail of structurally related compounds. During infection, these substances may be modified by the host plant of the fungus. The living plant might change the chemical structure of toxins as a major detoxification strategy and produce so-called masked mycotoxins as they are less toxic for the plant.

Examples of (i) modified forms of trichothecene, DON, are 3-acetyl- and 15-acetyl deoxynivalenol and (ii) masked forms are deoxynivalenol-3-glucoside, deoxynivalenol-3-sulphate and deoxynivalenol-15-sulphate. These modified and masked mycotoxins escape detection by routine analytical methods which can lead to an underestimation of the magnitude of contamination upon analysis.

Another form of modification of mycotoxins which occurs in mammals is the conversion of AFB1, ingested through contaminated feed or food to AFM1 in mammalian milk. Other processes which may result in production of modified mycotoxins include processing particularly heating and fermentation,  Modified forms of other mycotoxins like ochratoxin A and patulin have also been reported

Toxicological data on modified and masked mycotoxins are limited, Regulations on maximum levels of modified mycotoxins in foods and feed are currently under discussion at the European Union.

Health implications of mycotoxins

Animals can demonstrate variable susceptibilities to mycotoxins, depending on genetic factors (species, breed, strain), physiological factors (age, nutrition, etc) and environmental factors (climatic conditions, husbandry and management).  In most developed countries the natural contamination levels of mycotoxins in animal feeds do not normally occur at levels that can cause acute or overt mycotoxicosis, e.g. hepatitis, haemorrhage, nephritis and necrosis of oral and eneteric epithelia, and even death.  Rather, the observed levels induce symptoms of chronic primary mycotoxicosis and immune suppression.  It is often difficult to observe or diagnose such manifestations of disease but certainly they represent the most common forms of mycotoxicosis in farm animals, e.g. reduced productivity, growth and reproductive efficiency, reduced feed conversion efficiency, milk yields or egg production.

As a result of their diverse chemical structures and differing physical and biochemical properties, mycotoxins exhibit a wide array of biological effects on mammalian systems and individual mycotoxins can be genotoxic, mutagenic, carcinogenic, embryotoxic, teratogenic or oestrogenic. Although acute aflatoxicosis in humans is rare, several outbreaks have been reported.  In 1967, 26 people in a Taiwanese farming community became ill with suspected food poisoning; 19 were children and 3 of them died. No post-mortem was performed but rice from the affected households contained 200 µg aflatoxin B1/kg which was probably responsible for the outbreak.  In 1974, an outbreak of hepatitis in India affected 400 people resulting in 100 deaths. The deaths were caused by aflatoxins found in corn heavily contaminated with A. flavus containing up to 15mg of aflatoxins per kg (Montville and Matthews, 2008).  In 2004, one of the largest aflatoxicosis outbreak occurred in rural Kenya, resulting in 317 cases and 125 deaths.  Contaminated maize was responsible for the outbreak and officials found aflatoxin B1 levels as high as 4,400 parts per billion (ppb), 220 times higher than the Kenyan regulatory limit for food (Lewis et al, 2005).

Toxicological effects of mycotoxins

The toxicological effects of various mycotoxins have been demonstrated in laboratory or experimental animals.  Imposing the absence of any amount of genotoxic mycotoxins would then be appropriate, if these toxins were not natural contaminants that can never completely be eliminated without outlawing the contaminated food or feed.  In these cases, the Joint Expert Committee on Food Additives (JECFA) of FAO does not allocate a Provisional Tolerable Weekly or Daily Intake (PTWI or PTDI).  Instead it recommends that the level of the contaminant in food should be reduced so as to be As Low As Reasonably Achievable (ALARA) (FAO, 2004). 

Aflatoxins are genotoxic carcinogens and are the most toxic of the mycotoxins.  They have been linked to liver cancer particularly in developing countries where implicated foods are known to contain high levels of aflatoxins.  It is not possible to determine the threshold levels below which aflatoxins have no effect and therefore no Tolerable Daily Intake (TDI) level has been recommended.  However it is recommended that concentrations of aflatoxins in food should be reduced to the lowest levels reasonably achievable. 

Ochratoxin A (OTA) has been shown to cause cancer of the kidneys in animals and the European Commission’s Scientific Committee for Food (SCF) has set a tolerable weekly intake of OTA of 120 ng/kg body weight. Patulin has been shown to cause haemorrhage in the intestinal tract of experimental animals. The SCF have set a provisional maximum TDI of 0.4 µg/kg bw/d.

Deoxynivalenol (DON) is immunotoxic and has been shown to cause growth retardation and reproductive effects in experimental animals, however there are no data on its effects on humans.  The T-2 toxin causes alimentary toxic aleukia (ATA) in humans and like DON, they have been shown to adversely affect growth, reproductive and immune systems of experimental animals.  Instead of setting a TDI for the trichothecenes, SCF set a TDI of 1 µg/kg bw/d for DON, a temporary TDI (t-TDI) of 0.7 µg/kg bw/d for nivalenol and a combined t-TDI of 0.06 µg/kg bw/d for T-2 and HT-2 toxins In 2010, JECFA converted TDI for DON into DON and its derivatives with provisional maximum tolerable daily intake (PMTDI at 1 µg/kg bw/d  and acute reference dose (ARfD) at 8 µg/kg bw/d (EFSA, 2013a, b).

Based on occurrence data and estimation of chronic daily exposure, nivalenol (NIV) was not of health concern in 17 European countries and being unlikely genotoxic, the TDI was set at 1.2µg/kg bw/d (EFSA 2013b). 

Exposure to high levels of fumonisins (B1, B2, B3) has been observed to cause liver and kidney damage in experimental animals.  The SCF set a TDI of 2 µg/kg bw/d for both fumonisin B1 and in combination with B2 and B3.   

The current tolerable daily intake (TDI) for zearalenone (ZEN) of 0.25µg/kg body weight (bw) per day was established by the EFSA Panel for Contaminants in the Food Chain (CONTAM Panel) in 2011; this was based on oestrogenicity in pigs. No new studies were identifed to change this TDI the CONTAM Panel therefore set a group TDI of 0.25lg/kg bw/d expressed as ZEN equivalents for ZEN and its  modified forms (EFSA 2016).

 

Regulatory limits for mycotoxins

Throughout the world there are many advisory bodies concerned with food safety, including the World Health Organisation (WHO), Codex Alimentarius Joint Expert Committee for Food Additives and Contaminants (JECFA), and the European Food Safety Authority (EFSA). They regularly assess the risk from mycotoxins and advise on controls to reduce consumer exposure.   

In the UK, the Food Standards Agency (FSA) is responsible for ensuring mycotoxin safety (UK/FSA, 2002).  The UK legislation on mycotoxins is harmonised with the European Union. In the EU, regulatory limits for mycotoxins permitted in food and animal feed are set by a range of directives and Commission regulations.

Table 3.  Regulatory limit of aflatoxins in EU and some countries

Country/region

Foodstuff

Total aflatoxins    (µg/kg)

China

Corn, Peanuts and their products

20

European Union

Cereals, peanuts, tree nuts, dried fruits

4

Japan

All foods

10 (B1)

Malaysia

Nuts (ready to eat)

10

South Africa

Peanuts

15

USA

All foods except milk

20

Table 3 shows regulatory limits of aflatoxins in the EU and other countries. Commission Regulation (EC) No. 466/2001 sets maximum permitted levels for mycotoxins in food and feed and new limits are introduced by amendments to this legislation.  For example, EC Regulation No. 1881/2006 set limits for aflatoxins.  The current EU limits for mycotoxins are as follows:

        •   Maximum limits for oilseeds 2 ppb (µg/kg) for aflatoxin B1 and 4 ppb for total aflatoxin; EFSA was asked to deliver a scientific opinion regarding the effect on public health of a possible increase of the maximum level (ML) for aflatoxin total from 4 to 10µg/kg in peanuts and processed products thereof. EFSA assessed the toxicology of aflatoxins in 2007 and the most recent evaluation was carried out by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 2016. Given the short deadline of this request, no new toxicological evaluation was performed by the CONTAM Panel, the CONTAM Panel therefore decided to use the cancer potencies estimated by JECFA (2016) for risk characterisation. The cancer potencies for an AFB1 exposure of 1 ng/kg body weight (bw) per day was established.

  • Oilseeds for further processing with limits of 8 ppb and 15 ppb for aflatoxin B1 and total aflatoxin respectively (these limits do not apply to oilseeds including groundnuts for crushing for refined vegetable oil production);
  • 0.1 ppb aflatoxin B1 in baby food and 0.05 ppb aflatoxin M1 in milk.  The limit for aflatoxins in rice for direct consumption is 2 ppb for aflatoxin B1 and 4 ppb for total aflatoxin.
  • The maximum limit for OTA is 10 ppb in dried vine fruits (currants, raisins, sultanas) and in soluble coffee, 5 ppb in roasted coffee, 3 ppb in all products from cereals intended for direct human consumption, 2 ppb for wines, grape juice, grape must and grape must concentrate, and 0.5 ppb for baby foods processed cereal-based foods for infants and young children. 

The maximum levels for infants and young children according to Directive 2006/125/EC and Directive 2006/141/EC are:

  • Aflatoxin B1: 0.10 µg/kg
  • Aflatoxin M1: 0.025 µg/kg;
  • Ochratoxin A: 0.5 µg/kg and the same maximum level for dietary foods for specific medical purposes, specifically for infants;
  • Patulin: 10 µg/kg;
  • Deoxynivalenol: 200 µg/kg;
  • Zearalenone: 20 µg/kg and the same level for maize-based formulae for infants and young children;
  • Fumonisins: 200 µg/kg for maize-based formulae for infants and young children.

Since EC regulation No. 1881/2006 was issued there have been several amendments to the permitted levels of various mycotoxins in miscellaneous food products. These amendments are listed in more detail below:

Commission Regulation (EU) No. 105/2010.

Setting maximum levels for certain contaminants in foodstuffs as regards ochratoxin A.

Commission Regulation (EU) No. 165/2010.

Setting maximum levels for certain contaminants in foodstuffs as regards aflatoxins.

Commission regulation (EU) No. 594/2012.

Amending regulation (EC) No. 1881/2006 as regards the maximum levels of the contaminants ochratoxin A, non dioxin-like PCBs and melamine in foodstuffs.

Analytical methods of surveillance

Commission Regulation (EC) No. 401/2006 gives comprehensive details for the sampling, analysis and control of mycotoxins in foodstuffs in the European Union (EC, 2006a).

Many of the standards for the method performance analysis for mycotoxins are set by the European Committee for Standardisation (CEN). Methods of analysis should be characterised by appropriate criteria namely accuracy, applicability (matrix and concentration range), limit of detection, limit of determination, precision, repeatability, reproducibility, recovery, selectivity, linearity, sensitivity, and measurement uncertainty.  The main analytical procedures for isolating the major mycotoxins (especially the aflatoxins) from complex biological matrices and ensuing separation and purification follow well-established flow patterns, viz. sampling, extraction, clean-up, separation, detection, quantification, and finally confirmation.  Although there are now well-established protocols for each stage of these analytical procedures which have been adopted and incorporated into legislation, modifications are regularly being devised to achieve more accurate and reproducible identification of individual and multiple mycotoxins (Sheppard, 2008).   

A cardinal feature of analytical processes for mycotoxins is the design and efficacy of the original sampling plan, since this is almost always impeded by the highly positively skewed distribution of the mycotoxins in the raw organic products that are being analysed.  All product-sampling steps should be carried out as accurately as possible, so that the final samples that will be chemically analysed are truly representative of the batch under examination.  Inappropriate or biased samples will obviously invalidate the resultant analytical data.  Guidance notes have been produced to provide best practice for sampling mycotoxin contamination of samples and they explain the legal requirements of Commission Regulation (EC) No 401/2006 laying down the methods for sampling and analysis for the official control of the levels of mycotoxins in foodstuffs. In addition to these Regulations, there are sampling protocols also available from the Codex Alimentarius standard CODEX STAN 193-1995 (CAC, 2016).

Analytical methods used for the determination of mycotoxins in foodstuffs cover a wide spectrum of analytical science. Fast, accurate and reproducible technique for detection and quantification of mycotoxins in foods and feeds are now available. Analytical methods are divided into (i) quantitative methods (Thin Layer Chromatography, TLC  combined with scanner; High Performance Liquid Chromatography, HPLC, in combination with fluorescence detector or Mas Spectrometry, MS, Liquid Chromatography with MS or tandem MS, LC-MS/MS; capillary electrophoresis, (ii) semi-quantitative methods (ELISA; lateral flow tests; direct fluorescence; fluorescence polarization immunoassay; biosensors (iii)  indirect methods (spectroscopy) and (iv) emerging technologies (hyperspectral imaging; electronic nose; aptamer-based biosensors). Trucksess and Zhang (2016) argued that for analytical methods to be practical, they should meet the basic guideline of reproducibility in different laboratory settings.

The use of certified reference materials (CRMs) has improved the quality and consistency of analytical results in this field. Another issue that has also been addressed is one of matrix matching. Unknown agents in a food or feed extract can sometimes depress (or enhance) the response of the analyte which will then give an erroneous reading when compared against a standard calibration curve prepared for that analyte. (Jakovac-Strajn and Tavcar-Kalcher, 2012). 

Analysis of mycotoxins in foods and feeds presents difficulties for laboratories because of the exceedingly low levels that need to be detected for legislative purposes. An associated issue is one of appropriate sampling to determine legal compliance. Product contamination is rarely uniform and inconsistencies in analyses, particularly at threshold limits, are not uncommon. However, it must be said that such variability is not only encountered with the analyses of mycotoxins. This is an issue that is common to all analytical procedures requiring trace levels of contaminants to be determined (inorganic as well as organic materials).    

Prevention and control of mycotoxins

Agricultural intervention to reduce mycotoxins is considered at pre- and post- harvest levels. Mycotoxins primarily enter into the human and animal food chains through agricultural products, mainly cereals, nuts and oilseeds or from products derived from them. Various potential mitigation approaches for the prevention and control of mycotoxins have been proposed and these include crop rotation, mixed crops, harvesting time, farminig techniques, plant resistance breeding, detoxifying agents (enzymes and binders) and genetic modification.

Mycotoxin contamination of seeds is mostly caused by inadequate storage conditions of harvested crops, however pre-harvest contamination of the seeds can also occur especially with Fusarium spp. producing zearalenone, trichothecenes, and fumonisins, while other fungal contamination can produce ergot alkaloids, tremorgen mycotoxins, and aflatoxins. Pre-harvest interventions include production of genetically enhanced resistant crop, good agronomic practices, harvesting crop at the optimum stage of development, biocontrol methods (e.g. use of atoxigenic A. flavus), chemical methods.

Post-harvest contamination by mycotoxigenic fungi usually occurs during storage and transportation and is normally caused by improper drying or re-wetting of the crop from condensation or rain.  Post-harvest control measures include physical methods e.g. improved storage conditions, transportation, sorting and chemical methods such as ammoniation.  Correct drying of seeds followed by efficient storage and monitoring is an effective post-harvest management technique to prevent mould growth.  Other techniques are used based on colour or visual appearance of decay or damage to separate out contaminated seeds, particularly oilseeds.  The possibility for sorting and physical treatment in case of non-compliance is limited to the cases of consignment, not complying with EU legislation but containing levels below the worldwide permitted level established for AFB1 and total aflatoxin.  Nuts labelled for direct human consumption found with levels of total aflatoxins above those for direct human consumption or as an ingredient and below the worldwide highest level established for AFB1 (20 µg/kg) and/or for aflatoxin total (35 µg/kg), can be re-labelled and sorted or undergo a physical treatment to reduce aflatoxin content under official control.  This requires that the transfer to the processing plant, the process and the sampling and analysis have to be performed under the official control of the competent authority.  After sorting and/or physical treatment, an official sampling and analysis must be performed to demonstrate that the nuts are compliant with the limits set for direct human consumption or use as an ingredient.  Similarly, nuts labelled for further processing found with levels above those set in legislation but below the worldwide highest level established for AFB1 (20 µg/kg) and/or for aflatoxin total (35 µg/kg)  (FAO, 2003), can be re-labelled and also be further sorted or undergo a physical treatment under official control as above.  However, Article 19 (2) (a) of Regulation (EC) No. 882/2004 provides that if the official control indicates that a consignment is injurious to human or animal health or unsafe, the competent authority shall place the consignment in question under official detention pending its destruction or any other appropriate measure necessary to protect human and animal health.  The appropriate measures could be a) destruction of the goods under official control and the costs are borne by the food business operator, b) use under official control for industrial purposes (non feed /non food uses), c) use under official control for oil extraction provided the resulting oil is refined to reduce any aflatoxin which may be present to acceptable levels and use under official control of the residual cake/meal for animal feeding after an appropriate treatment (detoxification) d) re-dispatch to the country of origin. 

Given that, worldwide, the highest level established for AFB1 is 20 µg/kg and for aflatoxin total 35 µg/kg these levels are considered as being upper limits above which consignments must be rejected.  These levels do also apply to other foodstuffs imported into the EU e.g. spices, melon seeds, sesame seeds.

The Hazard Analysis Critical Control Point (HACCP) is an internationally recognised food safety management system, however, application of HACCP principles to mycotoxin control is a relatively new approach, but is based on some very sound reasoning according to the European Mycotoxin Awareness Network (EMAN, 2012). In 1993, the CODEX published guidelines on application of HACCP. Now there are some very good reasons for the application of HACCP to prevent mycotoxin formation in the first place.

Most foods not of animal origin can be imported into the EU without any further controls except for the fact they must comply with all the EU regulations appropriate to the food. However when a specific food from a specific country is shown to be exhibiting excess levels of contaminants, including aflatoxin, then additional controls are applied before it is given a Common Entry Document and allowed into the EU.

These additional controls are defined in Commission Regulation (EC) No. 669/2009 which further strengthens the requirements of No. 882/2004 as regards the increased level of official controls on importation of certain food and feed of non-animal origin from countries outside of the EU. 

The system is comprehensive in that only certain ports with sufficient facilities to sample and test the consignments are designated as points of entry. The annex to this regulation is revised every 3 months (at the time of writing No. 1295/2014 of 4th December 2014 is in force). Only when a food has undergone additional checks and the contaminant found to be below the EU limits is the consignment provided considered to be within compliance.

In addition foods potentially containing aflatoxins are also controlled by Regulation No. 884/2014. This regulation is made under Article 53 of the General Food Regulation No. 178/2002 as a safeguard measure to protect the health of the EU citizens. In this case a similar system to the above is in place although with more stringent requirements; foods identified under this regulation gain entry to the EU via through designated ports of import. Special conditions governing the import of certain feed and food from certain third countries due to contamination risk by aflatoxins and repealing Regulation (EC) No 1152/2009 can be found in regulation EC 884/2014.

The additional controls are that each consignment has to be accompanied by a certificate of analysis performed by the competent authority of the exporting country together with a completed health certificate. The analysis has to be carried out in accordance with Regulation No. 401/2006.

Chemical preservatives such as organic acids (sorbic, propionic, acetic, benzoic) have been used to restrict the growth of mycotoxigenic fungi.  Reduction in the levels of aflatoxins has also been achieved with the use of ammonia either in solution or in gaseous form.  Studies have been reported on the use of phyllosilicate clays (hydrated sodium calcium alumino-silicate) to chemi-sorb aflatoxin in aqueous suspensions including milk.  Clinical and/or dietary intervention for aflatoxins include binding agents (chlorophyll, chlorophyllin), phase II enzyme inducers (sulphoraphane found in cruciferous and other vegetables, triterpenoids, Oltipraz), inflammation reducers (NSAIDs, green tea poly phenols) Hepatitis B vaccine which blocks insertional mutagenesis (Galvano et al, 2001, Groopman et al, 2008).

The influence of climate on the distribution of mycotoxins in food crops and feeds is now receiving some attention. Compounds in cereals such as nivalenol, ergot alkaloids, aflatoxins and fumonisins in maize are now appearing in areas and locations that had not been seen before due to changes in climatic patterns. These challenges require further surveillances and more refined exposure assessments.

The awareness of the toxic role of mycotoxins in the human diet and animal feeds would be greatly improved by the wider teaching and dissemination of mycotoxicology in courses in food science, analytical chemistry, food safety, nutrition, microbiology and environmental health.

References

Codex Alimentarius Commission, 1993. Codex Guidelines for the Application of the Hazard Analysis Critical Control Point (HACCP) system. Joint FAO/WHO Codex Committee on Food Hygiene. WHO/FNU/FOS/93.3 Annex II.

Codex Alimentarius Commission (CAC, 2016) Code of Practice for the Prevention and Reduction of mycotoxins contamination in cereals. CAC/RCP 51-2003, revised 2016.

European Mycotoxin Awareness Network, 2012 http://services.leatherheadfood.com/eman/FactSheet.aspx?ID=79

European Mycotoxin Awareness Network. 2014. http://mycoglobe.ispa.cnr.it/Brussel/EMAN.pdf    

European Commission (EC), 2006a. Commission Regulation, (EC) No. 401/2006 laying down the methods of sampling and analysis for the official control of the levels of mycotoxins in foodstuffs http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:070:0012:0034:EN:PDF

European Commission (EC), 2006b. Commission Regulation, (EC) No. 1881/2006 setting maximum levels for certain contaminants in foodstuffs https://www.fsai.ie/uploadedFiles/Regulation_EC_No_1881_2006.pdf

European Commission (EC), 2009. Commission Regulation, (EC) No. 669/2009 Guidance for Enforcement Officers on increased levels of official controls on imports of certain Feed and Food of Non-Animal Origin of Known or Emerging Risks www.food.gov.uk/sites/default/files/multimedia/pdfs/ec6692009enforcerguide.pdf

European Commission (EC), 2011. Joint Research Centre. Mycotoxins Factsheet, 4th edition. http://irmm.jrc.ec.europa.eu/EURLs/eurl_mycotoxins/Documents/Factsheet%20Mycotoxins.pdf

European Commission (EC) 2014. Imposing special conditions governing the import of certain feed and food from certain third countries due to contamination risk by aflatoxins and repealing Regulation (EC) No 1152/2009 http://food.gov.uk/business-industry/imports/banned_restricted/highrisknonpoao

European Food Safety Authority (EFSA). 2013a. Deoxynivalenol in food and feed: occurrence and exposure. EFSA Journal, 11 (10): 3379

European Food Safety Authority (EFSA). 2013b. Scientific Opinion on risks for animal and public health related to the presence of nivalenol in food and feedEFSA Journal, 13 (6): 3262 http://www.efsa.europa.eu/

European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain (CONTAM) 2016, Appropriateness to set a group health-based guidance value for zearalenone and its modified forms. EFSA Journal, 14(4):4425

European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain (CONTAM) 2018, Effect on public health of a possible increase of the maximum level for aflatoxin total from 4 to 10µg/kg in peanuts and processed products thereof, intended for direct human consumption or use as an ingredient in foodstuffs EFSA Journal, 16(2):5175

Food and Agriculture Organisation (FAO), 2004. Corporate Document Depository.  Worldwide regulations for mycotoxins in food and feeds.  http://www.fao.org/docrep/007/y5499e/y5499e05.htm

Galvano, F., Piva, A., Ritieni, R. and Galvano, G. 2001. Dietary strategies to counteract the effects of mycotoxins: a review. Journal of Food Protection 64,120-131.     

Groopman, J.D., Kensler, T.W.,  Christopher P. Wild, C.P. 2008. Protective  Interventions to Prevent Aflatoxin-Induced Carcinogenesis in Developing  Countries. Annual Review of Public Health, 29, 187-203.

Jakovac-Strajn, B. and Tavcar-Kalcher, G. 2012. A method using Gas chromatography- Mass Spectrometry for the Detection of Mycotoxins from Trichothecene Groups A and B in Grains. Gas Chromatography in Plant Science, Wine Technology, Toxicology and Some Specific Applications. Dr. Bekir Salih (Ed.), In Tech Publisher. ISBN 978-953-51-0127-7. http://cdn.intechopen.com/pdfs-wm/30591.pdf

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UK Food Standards Agency, 2002. Survey of nuts, nut products and dried tree fruits for mycotoxins. Food Survey Information Sheet  21/02  http://www.food.gov.uk/science/surveillance/fsis2002/21nuts 

UK Food Standards Agency,  2003. Mycotoxins in oats survey http://www.food.gov.uk/news/newsarchive/2004/feb/174899

UK Food Standards Agency, 2004. Survey of baby foods for mycotoxins, Food Survey Information Sheet 68/04. http://www.food.gov.uk/science/surveillance/fsis2004branch/fsis6804

UK Food Standards Agency, 2005a. Survey of wheat for ochratoxin A, Food Survey Information Sheet 77/05. http://www.food.gov.uk/science/surveillance/fsis2005/fsis7705

UK Food Standards Agency, 2005b. Survey of spices for aflatoxins and ochratoxin A,  Food Survey Information Sheet 73/05. http://www.food.gov.uk/science/surveillance/fsis2005/fsis7305

UK Food Standards Agency, 2005c. Survey of maize-based retail products for mycotoxins, Food Survey Information Sheet 72/05 http://www.food.gov.uk/science/surveillance/fsis2005/fsis7204

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Institute of Food Science & Technology has authorised the publication of the following updated Information Statement on Mycotoxins, dated October 2018, replacing that of March 2015.

This updated Information Statement has been prepared by Professor Kofi E Aidoo, peer reviewed by professional members of IFST and approved by the IFST Scientific Comittee. 

The Institute takes every possible care in compiling, preparing and issuing the information contained in IFST Information Statements, but can accept no liability whatsoever in connection with them. Nothing in them should be construed as absolving anyone from complying with legal requirements. They are provided for general information and guidance and to express expert professional interpretation and opinion, on important food-related issues.