Mycotoxins are toxic compounds produced by different types of fungus, belonging mainly to the Aspergillus, Penicillium and Fusarium genera. They commonly enter the food chain through contaminated food and feed crops, mainly cereals. Dr. Bruce Cottrill is an expert in animal nutrition and a member of the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel). As a long-serving member of the Panel’s working groups on mycotoxins, Dr. Cottrill has been closely involved in developing EFSA’s risk assessments of mycotoxins in recent years. Since 2004, the Panel has produced 20 scientific opinions, mainly on a variety of Fusarium toxins, and is currently developing another four opinions, including one on metabolites and masked forms of certain Fusarium toxins, which marks a first for EFSA.
Overall, what has the Panel learnt from its work on mycotoxins?
B.C.: The highest concentrations of mycotoxins are found in cereal grains and grain products, and as a result these make the greatest contribution to both human and animal exposure. Estimates of chronic and/or acute dietary exposures to the different mycotoxins, based on the available occurrence data and using EFSA’s Comprehensive European Food Consumption Database, are generally below the established health-based guidance values for most of the population groups. Although the presence of these toxins in food and feed have been known for many years, there are still significant deficiencies in currently available toxicological studies, and there are still major gaps in our knowledge on their genotoxicity or carcinogenicity that need to be filled.
What impact is this body of work having?
B.C.: These scientific opinions have been produced at the request of the risk managers in the European Commission, and they have been able to use them to establish maximum limits in food and feed, thereby minimising the risk of adverse effects in humans and livestock. The opinions are also available to the wider scientific community, in the form of comprehensive reviews of the current state of knowledge of the occurrence and toxicity of mycotoxins, and therefore form a basis for identifying priorities for future research.
What has the Panel found particularly challenging about its work on mycotoxins?
B.C.: For most of these toxins, the lack of in vivo toxicity data has made it difficult to perform a full risk assessment. Moreover, most of these opinions have dealt with individual toxins; while it seems unlikely that they act in isolation, the data describing possible effects of combined exposure with other mycotoxins is very weak, and has been insufficient to establish the nature of any combined effects. At the same time, the database on occurrence has been limited, and as a result it has been difficult to provide reliable estimates of exposure for humans or livestock. For others, such as nivalenol and the emerging toxins enniatins and beauvericin, the lack of validated methods of analysis and the absence of certified reference materials has meant that it has not been possible to provide reliable estimates of exposure.
How did the Panel overcome these challenges?
B.C.: There is little direct action that the Panel can take to overcome these deficiencies, but each scientific opinion contains recommendations, directed to both risk managers and the wider scientific communities, for further research aimed at improving the risk assessment.
Will this benefit future scientific work on mycotoxins?
B.C.: For the wider scientific community these provide indicators of potentially useful areas of research, while to national authorities they have shown where improvements in surveillance of particular foods or feeds would improve risk assessment. In addition, EFSA gives grants for research projects to fulfil the identified data gaps and several EU Member State organisations have generated new data in these EFSA projects.
What was your personal contribution to these opinions?
B.C.: The fungi responsible for producing mycotoxins are most commonly found on cereals, which are important ingredients in the diets of livestock and companion animals (e.g. horses, pets). Aspergillus, Penicillium and Fusarium toxins have been implicated in a number of animal diseases, and therefore contaminated feeds pose a direct health risk to these animals. Moreover, since they can be transferred to animal products (milk, meat and eggs) post-ingestion, they also represent a potential indirect health risk to humans. As an animal nutritionist with an interest in EU livestock farming systems, I have advised the Panel on levels of feed, and particularly cereal grains, cereal by-products and cereal forage crops, that different livestock might consume, and using occurrence data estimated likely levels of exposure to the different mycotoxins. These data are then compared with published estimates of levels at which no adverse effects have been observed to identify possible risks to livestock. Having established levels of exposure, we have then used published estimates of carry-over from feed to food of animal origin, thereby identifying any potential risks to humans consuming livestock products.
How has your involvement influenced your approach to your own scientific research?
B.C.: My involvement in the Panel and the Working Groups has reinforced for me the importance of interdisciplinary communication and collaboration in the area of risk assessment. While it’s often easy to focus on the detail, it’s necessary to see it within a wider context.