Mycotoxins, the invisible evil. The feared natural contaminants, highly toxic to humans, represent a permanent warning. How to prevent their formation and manage related food safety risks? From 10 to 12 June 2019 Rome hosts the international conference on the subject (poster attached). An event that for twenty years has brought together leading experts to share updates on the state of the art, scientific and regulatory evolution. Following the interview with Carlo Brera, one of the leading experts on mycotoxins at international level, researcher at the Istituto Superiore di Sanità and organizer of the congress.
Doctor Brera, is there a concrete risk for the population deriving from the consumption of common foods, such as pasta, bread, biscuits?
From the scientific evidence acquired so far, the population in general is not to be considered particularly at risk, except for children of post-infantile age (3-10 years) and partly adolescents, based on their unfavorable body weight and consumption of foods not dedicated to this range: in fact, they eat foods designed and suitable for consumption by adults, as there is no differentiation as is the case with baby food (intended for infants and children up to 3 years of age), subject to lower limits for the presence of contaminants.
What are the factors responsible for the formation of mycotoxins?
The main factors to refer to as a source of risk are mainly those related to the environmental conditions that cause stress both to the plant and to the mold itself. In particular, thermal, nutritional and water stress certainly represent favorable conditions for the development in the field of fungal colonies with the probable consequent production of mycotoxins.
Are mycotoxins still a major threat to crops?
Compared to 20 years ago, farmers - as well as all operators in the feed food system - have improved attention to the problem, but a satisfactory level of prevention has not yet been achieved. The risk remains high under certain climatic conditions. 2014 did not go well, but the last high risk condition dates back to 2012 and was repeated as in 2003. Evidently the lesson has not been learned. Also this year there were signs of a strong attack of molds in the field.
16 years ago, the vintage was characterized by 6 months of drought, with no rain from May to October. Ideal conditions for a strong growth of aflatoxin B1. At that time, farmers were unable to intervene, as irrigation is never enough to compensate for such a level of aridity. The grain dried in the field prematurely, was then harvested prematurely with a humidity below 22%, favoring the formation of mold which led to frightening levels of aflatoxin. All contaminated crops were segregated in silos. The biogas industry took off on that very occasion, when it disposed of 30-40% of those contaminated crops.
In case of contamination, are there effective treatments to eliminate mycotoxins from food? Roasting and drying, for example?
Mycotoxins cannot be eliminated. They are natural contaminants produced by mold or mildew due to favorable climatic conditions. They are ubiquitous, they grow at all latitudes, they are also highly thermostable. Prevention is the only way to counter them, but right here the biggest obstacle stands out.
What preventive measures can be taken?
On the measures to be taken in the field to combat the formation of mycotoxins in maize and wheat, there are good practices codified in official documents. Such as the 1996 Recommendation of the European Commission, the Recommendation of the Codex Alimentarius, the guidelines of the Ministry of Agricultural Policies (drawn up by Professor Amedeo Reyneri, who will be present at the congress).
What do good agricultural practices involve?
Good practices recommend adopting a holistic approach characterized by many components such as crop precession (crop rotation, ed), which allows to contain the propagation of mycotoxins. This is in fact more probable when cultivating species palatable to the mushrooms that originate these toxins, such as corn and sorghum immediately afterwards. It is then necessary to resort to biological control, also using antagonistic insects. And to resort, if necessary, to the tanning of the seed.
Sowing must take place on plowed, not firm soil. We also recommend the control of weeds and 'pests', the use of fungicides, correct irrigation. And the control of the mechanization of the harvest, to prevent the grain from being damaged by mechanical tools, as any wound to the grain or to the kernels becomes nourishment for the growth of molds during storage. Other preventive measures refer to the final phase, namely immediate drying of the crop and careful management of the silos.
Are there also innovative counter measures?
The best solution is plants that are resistant to fungal attack and the production of mycotoxins. Varieties obtained by isogenic lines, from corn or wheat (non-GMO, ed), created by Italian universities, by CREA, by the Cereal Institute of Bergamo. Although there are numerous studies and varieties of seeds registered as resistant to fungal attack, such solutions are not yet adopted in a systematic way. The problem is that the farmer, at the time of sowing, does not know what the climatic conditions will be in the following months. And he is not willing to pay more for a resistant strain in the absence of guarantees on the return on the increased investment.
A good practice that has also been taking hold in Italy for about three years is biocontrol, developed in the United States in the 80s. It involves spraying the cultivated field with fungal strains identical to those that produce mycotoxins but characterized by being non-toxic. By playing on the quantity, the non-toxic fungal species is induced to prevail over the other, obtaining a reduction in the growth of toxigenic mold congenial to the production of aflatoxin B1, which is highly toxic.
Another possible solution, adopted in various countries outside our own, is the use of genetically modified (GM) maize varieties, which inhibit the formation of some mycotoxins (fumonisins). Spain grows them, but Italian farmers cannot. Both for the ban on sowing in force in Italy, and for the fragmentation of our agriculture into small batches which would make it impossible to avoid contamination between GM crops and conventional ones. A ban on sowing but not on consumption. In fact, as is well known, our country still imports GMO feed to feed the farms from which excellent raw materials such as Parmigiano Reggiano or Parma ham originate. (A paradox already on this site highlighted, editor's note).
With so many preventive measures available, why do mycotoxins in the field remain a constant threat?
It takes little to describe good practices, but a lot to implement them. And the farmer must first of all secure an income. I have always said this also in the international context, agricultural policies aimed at supporting farmers would be needed, otherwise there is no prevention that matters, because no one recognizes the greater costs that arise from the farmer.
Adopting agronomic practices that make it possible to obtain a harvest without mycotoxins costs more, has a plus, but the harvest is always paid the same price. If, on the other hand, it is contaminated, it is paid even less. In this situation it is logical that the farmer tries to do his utmost to protect his production, but without exceeding a certain level, otherwise he would no longer have an economic return.
Do the same considerations also apply to organic farming?
Foods from organic farming should be better protected than the risk of contamination by mycotoxins, because the aforementioned good agronomic practices are foreseen by 'default'.
The frequency of contamination is much higher in the conventional. But any contamination on a biological field can reach much higher levels than in the conventional one, because no pesticides, herbicides and insecticides are used.
In a recent survey on the reports to the RASFF of food consignments contaminated by mycotoxins, we have noticed that the countries of origin of the risk are always the same. And among these the United States, the home of 'biocontrol', stand out. Why?
In Europe we have very strict and restrictive regulations, based on the precautionary principle, while the United States are based on risk assessment and favor the marketability of the product.
In addition, despite the advanced research and the use of GM crops resistant to mycotoxins, the United States is characterized by climatic conditions that do not allow to guarantee compliance with the limits in force in Europe. However, this should not scare us, because we enjoy an excellent control system at the European borders.
How are border controls in the European Union regulated?
The European Commission has issued two specific regulations to modulate controls in consideration of risk factors. Both regulations - reg. CE 669/09 on pathogenic contaminants and reg. EU 884/14 on aflatoxins - bear a table with country, matrix, frequency of controls based on risk and parameters to be controlled (salmonella, aflatoxins, ochratoxin, etc.). They are updated every 4 months and the percentages of matches to check may change.
15 years ago, for example, problems emerged with Iranian pistachios, contaminated with aflatoxin B1. The European Commission, then DG SANCO, decided that 100% of incoming consignments should be subject to controls. A delegation of inspectors was then sent to Iran to verify the source of the problem. In a few years the situation improved and controls dropped first to 50%, then to 20%. Thanks to the remedies shared with the experts of the European mission and their effective adoption by local producers.
Currently, the reg. EU 884/14 provides, in some cases, the control of one batch out of 2, when the origin is at risk of aflatoxins. What is not screened at the European borders is in any case subject to controls on the territories of the Member States.
Why does Italy appear little in the RASFF among the flags of consignments contaminated by mycotoxins?
Historically, Italy has always been in the first places for alerts as we have a network of controls that is unique in Europe in terms of organization and efficiency. For this reason it is highly probable that importers will not land in Italy the food consignments contaminated with mycotoxins. And consequently, not finding any, Italy does not often appear in the RASFF for this type of alert, although in general it is among the European countries that send the greatest number of reports.
What is the level of controls and the risk of mycotoxins in the national territory, therefore primarily on Italian productions?
In 2016, I asked the Ministry of Health to organize a national food mycotoxin risk control plan. Together we drafted the plan, which lasted until 2018 and is still in place. All regions contributed. Now I - risk assessor - have at my disposal a well-organized database for the quantity and quality of information.
6 data, sorted according to the standard required by EFSA, allow me to investigate the risk of exposure to mycotoxins in Italy. A volume that also makes us competitive on a European level. When the Commission asks Member States for data on the level of internal risk, it is important to provide a good amount of it, in order to have more weight in the decision-making process.
The risk of exposure of the Italian population to mycotoxins still presents some problems. But no major criticalities emerge, based on the analyzes that I will bring to the congress.
Doctor Brera, can you tell us something about the congress on mycotoxins that you have organized in Rome.
The first day, June 10, is entirely dedicated to analytical methodologies on mycotoxins and plant toxins. This year it takes place in a prestigious location, the Nobile Pharmaceutical Chemical College, via in Miranda 10, inside the Roman Forum. We will be inside a consecrated church. A green door at the back opens in front of the only temple still intact. The other two days - dedicated respectively to risk management and risk assessment - are instead held, as tradition, at the Higher Institute of Health.
Among the numerous speakers of international standing, Dr Frans Verstraete of DG SANTE of the European Commission stands out, who will present the very latest news on the subject. Representatives of all the major organizations active in the mycotoxin sector are also present. CEN, European Committee for Standardization, reference body for the procurement of reference methods for analyzes on mycotoxins. The Ministry of Health, EFSA, CREA, vil CNR of Bari and various universities (Turin, Piacenza), the Milling Technologists Association, Coldiretti and others.
ATTACHMENT Program_VI National Congress of Mycotoxins
A professional journalist since January 1995, she has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic studies on food and has published the book "Reading labels to know what we eat".
