Mycotoxins in grain – an overview of risks and solutions

15. Sep, 2022
Short read sums up why mycotoxins have always been a threat to health and agricultural production and the options to mitigate the risk.

Why fungi produce mycotoxins is an interesting topic in itself, but whatever the reason for their production, the presence of mycotoxins in grain presents a risk to the safety of food and feed products.


Vigilance is the therefore the word that comes to mind when considering the risk from mycotoxins to the grain supply chain. Testing regimes are required and protocols for the management of contaminated grain must be strictly followed to prevent the well-known health risks associated with mycotoxins.  


When protocols fail
The concern is that all it takes is a slight deviation from these trusted protocols for significant, health-threatening problems to occur. 


In Africa, aflatoxins found in maize and groundnuts is considered as the major cause of liver cancer, accounting for up to 40% of the cases. A major cause is that food shortages lead farmers to harvest their maize too early, with the immature grain being more susceptible to fungal infection. Other reasons are that the contaminated maize is not managed according to good agricultural praxis (GAP) and incorrect drying. 


All it takes are a few weak spots in the supply chain to allow food safety risk to occur.


Are mycotoxins such a big problem? 
The short answer is yes – mycotoxins are a persistent problem that change year by year and that depends very much on weather and the agricultural and manufacturing practice. What’s more, once present, mycotoxins cannot be removed from the supply chain. 


There are many studies that have tried to estimate the extent of mycotoxin contamination in global food crops supply. An often-cited report from the UN Food and Agricultural Organisation (FAO) stated that up to 25% of the global food crop was contaminated with mycotoxins. However, the origin of the data used to make this statement is largely unknown.


In a recent paper, published in the scientific journal Critical Reviews in Food Science and Nutrition, the authors discussed the validity of this statement. They found that current mycotoxin occurrence, that is samples with a level of mycotoxins above the EU limits, confirmed the initial FAO estimate of 25% contamination. Looking at data from BIOMIN(R), the authors conclude that detectable levels of mycotoxins may be found in up to 60-80% of the samples (Eskola, M., Kos, G., Elliott, C.T., Hajslova, J., Mayar, S. and Krska, R. 2020 Worldwide contamination of food-crops with mycotoxins: Validity of the widely cited FAO estimate of 25%.  Critical Reviews in Food and Science and Nutrition 60:2773-2789).


In short, mycotoxins most be considered as a risk in any type of crops and relevant control points must be in place to ensure safe food and feed.

Risk management strategies 
In terms of risk management, there are several areas where mycotoxins can be controlled within the supply chain. 

Ultimately, prevention of fungal growth is the best strategy, and studies have shown that good agricultural praxis and biological control agents can be used to limit the growth of the fungi responsible for mycotoxins. A longer-term alternative is to breed cereal varieties that are more resistant to fungal contamination. In addition, crop rotation systems as defined in Codex Alimentarius: ‘Code of Practice for the Prevention and Reduction of Mycotoxin Contamination in Cereals,’ can reduce the chance of contamination by avoiding the planting of the same crop in the same field, for two consecutive seasons. This can help to reduce the inoculum in the field which may originate from post-harvest debris containing fungal spores.

The use of targeted fungicides is an obvious intervention that can reduce the risk of mycotoxins. However, growing consumer awareness and intolerance of the use of chemical agents in the production of grain crops could limit the efficacy of this control measure and could have an undesired backlash from consumers and media.


When considering crops for animal feed in the supply chain picture, there are absorbents that can be used to remove the mycotoxins as well as detoxification technologies such as enzymes which can break the mycotoxins down to harmless by-products.


Proactive management of the mycotoxin problem

Clearly, greater engagement with these proactive steps (GAP) to prevent or remove the food safety risk from the grain play an important part in reducing the threat. However, the strongest tool that we currently have at our disposal to manage the risk from mycotoxins is the systematic testing and rejection of contaminated grain.


Testing methodologies have improved significantly over the years. The speed with which mycotoxin analysis can be performed, combined with the sensitivity of the analysis, has greatly enhanced our ability to identify problems and remove them from the supply chain. 


However, a changing climate potentially increasing and change the occurrence of mycotoxin contamination, all stakeholders in the supply chain will have to be more vigilant than ever. 


In conclusion, we will have to use all the available tools at our disposal to ensure food safety across the grain supply chain.