New way to detect fish poison ciguatera
Fri, 11th Nov 2011
Download as mp3
from the show Glittering seas: the science of ocean bioluminescence
Imagine eating a piece of fish that looks, smells and tastes completely normal, but a few hours ater you’re stuck in the toilet, vomiting and with tingling in your arms and legs. Well, this can happen if the fish you eat is contaminated with ciguatera toxin. This affects fish in tropical waters that eat a dinoflagellate species of algae that make the toxin. It affects between 20-60 thousand people every year and is the most common form of food poisoning caused by a natural toxin.
Testing fish for the toxin has up until now been a lengthy and time consuming
process, involving injecting purified samples into mice, and watching to see if
they become ill. Now Kentaro Yogi and his colleagues in Japan have developed
a much faster and effective way of testing for the toxin, which has also allowed
them to identify 15 different forms of the toxin present in fish species caught in different areas, as well as identifying differences in the dinoflagellates responsible for producing the toxin.
The team used liquid chromatography tandem mass spectrometry to analyse the
toxins, which were extracted and purified in a similar way to the mouse bioassay
method. The peaks obtained from the analysis were compared with known reference
samples of the toxins and they accurately showed the separate toxins found. The
team believe that with the production of more reference samples of the various toxins from extraction from natural sources and through synthetic chemistry, this method of detection could become widespread and would improve the speed and accuracy of testing for this unpleasant toxin.