500 poisonings trigger warning on reef fish

PUBLISHED : Wednesday, 14 March, 2007, 12:00am
UPDATED : Wednesday, 14 March, 2007, 12:00am

Bigger the catch, bigger the risk of illness, union boss warns

A new warning has gone out about coral reef fish after a study found that almost 500 people have suffered from fish poisoning in the past three years - most from a toxin commonly found in reef fish.

Experts from the Centre For Food Safety also warned consumers against buying, handling or eating dried or fresh pufferfish or porcupine fish, although poisoning from these fish is rare.

There were 148 cases of fish poisoning involving 462 people during the period studied, with 130 of the cases involved ciguatoxin, which comes from a micro-organism that builds up in reef fish.

It was the latest in a series of alerts about the perils of reef fish, which are among the most popular fish on Hong Kong tables.'It is difficult to distinguish the toxic substance from its appearance. This toxin is highly stable and cannot be destroyed by cooking or refrigeration,' researcher Ho Yuk-yin said.

'Therefore we advise the public to limit the consumption of coral reef fish and avoid eating the skin, viscera and roe of the fish.'

Dr Ho also warned against drinking alcohol or eating nut or seed products while eating reef fish as these could increase the severity of ciguatoxin symptoms.

Other poisoning cases involved less toxic or less common substances, including 13 by histamine - produced by improper storage of some species - and five by tetrodotoxin, found in the notoriously hazardous pufferfish.

Dr Ho advised people not to purchase or handle any kind of fish known to harbour tetrodotoxin, including dried or fresh pufferfish or porcupine fish.

'There was a case last year when a man bought a dried porcupine fish from the market to make soup and he was poisoned,' he said.

Histamine is produced by improper storage of fish like tuna, sardine and mackerel, which Dr Ho advised should be properly packaged and kept at 4 degrees Centigrade or below.

Hong Kong and Kowloon Fish Trade Workers Union chairman Tsang Sik-ming warned against buying big coral reef fish and said consumers should favour farmed fish.

'Big fish usually have more toxins stored in their heads or internal organs so it is more dangerous to eat them, and fish raised in farms are safer because they are kept away from poisonous seaweed,' he said.

ParknShop spokeswoman Jasmine Hui said the supermarket chain had internal guidelines 'and we do not sell any fish that weighs over 4kg to ensure safety for our customers'.

Wet market fish store owner Mr Lo said consumption of reef fish dropped after a poison scare but usually picked up when there had not been one for while.