The Centre for Health Protection is investigating five food poisoning cases suspected to have been caused by fish containing ciguatoxin.

Sixteen people, aged five to 63, developed symptoms including mouth and limb numbness and diarrhoea after eating large coral reef fish, including flowery grouper and grouper-like fish, on September 19 and 20.

Their symptoms were generally mild and some sought medical attention at hospitals. One 63-year-old woman is in stable condition in a private hospital.

The centre urges people to be extra cautious when consuming large coral reef fish as they can contain ciguatoxin which may cause food poisoning.

To prevent ciguatera fish poisoning:

* avoid consuming large coral reef fish - the bigger the fish, the higher the risk of ciguatera poisoning;

* avoid eating the internal organs especially the liver and gonads where the toxin tends to accumulate;

* eat only a small quantity of coral reef fish at any one meal;

* do not consume coral reef fish with alcohol and nuts; and,

* seek medical care when symptoms appear.