The Centre for Health Protection is investigating a suspected food poisoning case involving 13 people.

Four men and nine women, aged 21 to 25, developed abdominal pain, diarrhoea, vomiting and fever after having lunch on a boat trip on June 29.

Nine sought treatment from private doctors, public or private hospitals. Two of them were admitted to a Sha Tin private hospital while one was admitted to a Kowloon private hospital. All are stable.