SINGAPORE - The National Environment Agency (NEA) demoted the food hygiene grades of Michelin-starred Summer Palace and the Regent Singapore's banquet kitchen from "A" grade to "C" from Monday (Jan 29), after 43 patrons were suspected of getting food poisoning from a wedding lunch at the hotel.

In an advisory issued on Monday, NEA said that the people had stomach flu symptoms after eating food at both places on Nov 11 last year.

Replying to queries from The Straits Times, a Regent Singapore spokesman said that all 43 cases were not from guests dining in Summer Palace, but instead from a lunch wedding banquet held at the hotel that day.

Summer Palace was involved because its kitchen staff also prepared food for the banquet. The Cantonese restaurant in Regent Singapore, known for its dim sum, received one Michelin star last year.

The spokesman said that investigations from the authorities could not pinpoint the exact source of the suspected food poisoning, but that inspections showed lapses in the kitchens of both establishments, which is why NEA downgraded both the banquet kitchen and Summer Palace.

"It is unfortunate that this incident happened," said the spokesman, adding: "All 43 guests were contacted by the hotel to acknowledge the situation and extend our apologies."

She said that the hotel compensated the banquet organisers, though she declined to reveal the details of the offer, and that Regent Singapore invited the 43 guests for a complimentary dining experience.

The spokesman said that since last November, the hotel has implemented weekly food hygiene meetings, as well as walk-through inspections by the management team, in addition to monthly training sessions with food handlers.

She added: "We will continue working hard in this area to restore confidence in the hotel."

The two establishments previously had an "A" food hygiene rating according to NEA's website, and the Regent Singapore spokesman said this was the first time either place received a downgrade.

Eating establishments in Singapore are graded according to their hygiene, cleanliness and housekeeping standards. Those that score at least 85 per cent receive an "A" grade, while those of the lowest "D" rating receive a score of between 40 per cent and 49 per cent.

The "C" grade is establishments that score in the 50 to 69 per cent range.

NEA said that the new grade will be revised in 12 months and the premises will be kept under surveillance in the meantime.