The hazards of catching parasitic herring worms through eating raw fish are well known in the Far East, particularly Japan, where it is a recognised public health problem. Now cases are being reported in the UK, according to the British Journal of Clinical Practice. There are no drugs that can kill the worm (a nematode) and an operation is necessary.
But Sinclair Beecham, managing director of Pret a Manger sandwich shops, where sushi is a popular dish with customers, said freezing fish and using farmed salmon is the answer. 'With perfect-tasting sushi, you pull the fish out of the water, cut it up and serve it raw. But obviously we cannot take risks with our customers and under the new EC laws have developed our products so that we either use cooked fish or raw fish which has previously been frozen. This removes any danger of nematodes,' he said.
People suffering from the worm show symptoms that include acute stomach pain and sickness. Sometimes the larvae penetrate the intestinal wall. But doctors may be fooled into thinking the patient has appendicitis, food poisoning or Crohn's disease. A case reported in the journal involved a Japanese woman, 43, living in London, who had to have surgery to remove the parasite after suffering abdominal pain lasting 36 hours.
Once common in the Netherlands, herring worm has been eradicated by strict curbs on storage of raw and pickled fish.