Natural Toxins
Background
Toxic compounds present in food and water are often associated with a bacterial or chemical contamination. In many cases this is true however another important source of toxins in our food and water supplies comes from nature itself. These toxins can be derived from sources such as plants, fungi and algae and can cause symptoms ranging from mild food poisoning to death.
Research within The Institute of Agri-Food and Land Use on Natural Toxins
The major themes of natural toxin research within the Institute centre on phycotoxins and mycotoxins. The development of novel and innovative means of detecting the presence of a range of these toxic substances within food and water samples utilising biosensor based technologies has played an important part of the research in recent years.
Marine Toxins
Toxins secreted by algae and which concentrate in shellfish are a major hazard to the consumer and can bring huge economic losses to the aquaculture industry. The existence of many of these toxins has been known for some time and testing procedures using animal bioassays became the standard means of monitoring for their presence. However, due to serious concerns with regards to the effectiveness of these procedures and the use of animal based bioassays which cause enormous suffering to the animals alternative means of monitoring have been sought for several years.
Researchers at Queen’s University had pioneered the use of optical biosensor technology to detect a wide range of drug related contaminants in foods. This technology produced by Biacore in Sweden has since been applied to the complex problem of marine toxin monitoring.
The first research was performed developing a biosensor assay Domoic Acid (a member of the Amnesic shellfish poisons). The data generated during this project was highly promising and led to more recent research efforts on the more complex Diarrhetic Shellfish Poisons and Paralytic Shellfish Poisons. Significant progress has been achieved in the development of biosensor assays which can replace the Mouse Bioassay (MBA) procedures for these toxins.
Funding of Marine Toxin Research
Substantial research funding has been won to investigate the feasibility of developing biosensor based technologies to replace the MBA. The European Commission 6th Framework Programme (FP6) is currently funding Detectox, a European wide project aimed at developing biosensor procedures for the DSP research. In addition funding from the National Oceanic and Atmospheric Administration in the USA helps support research activities at Queen’s in a collaborative research project with Dr Greg Doucette, leader of the NOAA marine biotoxins programme.
Safefood, an All-Island research funding body has also supported the Queen's researchers in development of a biosensor assay for azaspiracid, an important member of the DSP family. The PSP research is also funded by FP6. An important work package in the Integrated research project Biocop (www.Biocop.org) relates to the development of a broad spectrum biosensor assay for the family of toxins.
Major Research Collaborations
The Queen's group has developed excellent research collaborations with Dr Greg Doucette, leader of the NOAA marine biotoxins programme, Professor Luis Botana, head of the European Community Reference laboratory in Spain and Dr. Jordi Molgo, Director of Research at the Laboratoire de Neurobiologie Cellulaire et Moléculaire in Paris.
Major Scientific Outputs
- Campbell, K., Stewart, L.D., Fodey, T.L., Haughey, S., Doucette, G., Kawatsu, K. and Elliott, C.T. (2007). An assessment of specific binding proteins suitable for the detection of paralytic shellfish poisons (PSP) using optical biosensor technology. Analytical Chemistry, 79: 5906-5914.
- Traynor, I., Plumpton, L., Fodey, T.L., Higgins, C., Elliott, C.T. (2006). Immunobiosensor detection of domoic acid as a screening test in bivalve mollusks: Comparison with LC based analysis. JAOAC, 89: 868-872.
Mycotoxins
Mycotoxins are toxic chemicals produced by a number of different fungal species. Those fungal species which infest food stuffs consumed by farm animals and humans are of the greatest health and economic importance. The total number of mycotoxins is unknown however it is estimated they number in the thousands and to date over 300 mycotoxins have been identified and characterized, mostly under laboratory conditions.
The major toxigenic species of fungi are Aspergillus, Penicillium and Fusarium while Claviceps and Stachybotyrs are also considered important. These genera of fungi are responsible for the production of aflatoxins, fumonisins, trichothecenes, ochratoxin A, zearalenone and ergot alkaloids which pose the greatest risk to humans and animals producing acute and chronic manifestations. Symptoms include hepatitis, haemorrhage, nephritis and necrosis, slower growth rates, reduced reproductive efficiency, feed conversion efficiency, milk and egg yields.
Mycotoxins are considered unavoidable contaminants in foods because they are not entirely eliminated by good agricultural practices and good manufacturing practices therefore small amounts of these contaminants may be legally permitted in foods and feeds, provided the levels are not injurious to human and animal health.
Since the 1960's substantial research has been undertaken to develop accurate and sensitive analytical methods for identifying and quantifying mycotoxins in food and feed which is challenging due to their chemical diversity and the range of matrices in which they occur. Researchers at Queen's University are currently investigating the development of rapid assays for the detection of trichothecenes in foods and plants.
