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In the Galician rías, red tides caused by dinoflagellate blooms have become increasingly frequent in recent years, leading to recurrent closures of shellfish farming areas, particularly in the Rías Baixas. These closures are due to the presence of Paralytic Shellfish Toxins (PST), which make shellfish like mussels dangerous for human consumption. However, for Cifga Laboratory, a producer of reference materials accredited under ISO 17034, these red tides represent a valuable source of contaminated material, allowing the extraction of pure toxins essential for water and marine product analysis.
The extraction process of paralytic shellfish toxins
The first step in this process is the acquisition of contaminated mussels from areas closed due to the presence of toxins. These mussels, which cannot be sold for consumption, become the raw material for toxin extraction in the laboratory. The extraction process follows several key steps:
- Dehydration and grinding: The contaminated mussels are fully dehydrated, removing all moisture to facilitate the next steps. Once dehydrated, the mussels are ground into a fine and homogenized powder. This concentrated powder contains the toxins that need to be extracted.
- Extraction: The homogenized sample is extracted with acetic acid in a boiling water bath, all water-soluble compounds including PST will be extracted and this extract wil be further cleaned using solid phase extraction. This step is crucial for obtaining a concentrated toxin sample.
- Purification by HPLC preparative system: When finer purification is required, we turn to preparative HPLC. The final result is a purer product, which will be used to produce certified reference materials, ensuring reliable analysis.
Turning red tides into raw material
For most of the shellfish industry, red tides and shellfish farm closures represent significant economic losses. However, the contaminated raw material obtained allows the extraction of a wide range of toxins, not only paralytic shellfish toxins but also amnesic and diarrhetic toxins, which are used in toxicity studies worldwide.
The reference materials produced by Cifga from these toxins enable quality control laboratories, both in Galicia and internationally, to analyze water toxicity and marine products. This contributes to ensuring food safety and preventing public health risks.
In conclusion, Cifga's toxin extraction work turns a natural threat, such as red tides, into an opportunity to develop crucial analytical tools. These reference materials, produced under strict quality standards, are essential for protecting health and preserving the marine resources of the Galician rías.
