Over The Horizon

Testing for Toxins

Dr Toshiyuki Suzuki of Japan's Tohoku National Fisheries Research Institute is working with the toxic micro-algae research team at the Cawthron Institute in Nelson to develop a chemical method to measure two recently-discovered substances, gymnodimine and yessotoxin, which can sometimes cause "false positive" results in tests for shellfish toxins.

Cawthron scientist Dr Henry Kaspar says the research will ultimately refine the procedure for testing for toxins, which will make New Zealand shellfish more widely accepted in overseas markets. New Zealand currently exports around $23 million worth of shellfish to East and South-East Asian countries.

A false positive result occurs when substances such as gymnodimine and yessotoxin, which are not considered harmful to human health, display reactions in mice which are similar to those exhibited by hazardous bio-toxins.

"By developing a chemical method which can be used to identify these substances, we could check whether positive results in mice are due to real toxins or harmless substances," Kaspar says.

The research may also lead to exportable technology being developed in the form of laboratory test kits for these compounds, he says.