In the wake of the Summer Palace food poisoning case (Hygiene rating downgraded after suspected food poisoning; Jan 31), can the authorities explain what steps are taken to establish that a mass food poisoning has taken place?

In the above case, where 43 people came down with stomach flu symptoms following a wedding lunch, the victims may have known each other or the organiser well enough to discuss their medical issues among themselves and thus establish a common link.

However, how would the National Environment Agency have gone about investigating a case where the food poisoning victims were unrelated and had eaten from a stall in a food centre?

These people would have come from different parts of the island and then gone their separate ways after eating and would have fallen sick only after they reached home. Each might think that theirs was an isolated case.

Is there a national database of reported food poisoning cases that is maintained by the medical services, so that an eatery that constantly comes up on the list is flagged?

Yeo Shuan Chee