The Centre for Health Protection is investigating a suspected food poisoning case after 55 people who had a buffet lunch in a Causeway Bay restaurant fell ill.

The affected, 20 men and 35 women aged six to 68, are primary school students and their parents who took part in a lunch the school organised on April 24.

They developed diarrhoea, nausea, abdominal pain, vomiting and fever within 55 hours after the meal. Thirty-three of them sought medical treatment and none required hospitalisation.

About 200 students and parents had attended the lunch buffet and the outbreak is believed to be a bacteria food poisoning case.

Stool samples will be collected from the patients and investigations are in progress to confirm the number of people affected and the source of outbreak.

To prevent food borne diseases, people are urged to:

* clean and cook food thoroughly before eating, particularly crustacean and bivalve seafood such as shrimp, crab, oysters and clams;

* handle raw and cooked food with separate utensils to prevent cross contamination;

* keep raw and cooked food separately;

* store food in a refrigerator (at four degree Celsius or below) and adequately reheat leftover food before eating;

* wash hands before eating and after going to toilet; and

* keep the environment clean.