No links have been found between the different food poisoning outbreaks at Mandarin Orchard Hotel, FoodTalks Caterer and Manufacturer, Tung Lok Millennium and Spize Restaurant at River Valley Road.

This was the conclusion reached by the authorities based on epidemiological findings, clinical presentation and laboratory findings.

The Ministry of Health (MOH), National Environment Agency (NEA) and Agri-Food and Veterinary Authority (AVA) said in a joint statement on Friday, Dec. 14 that they have completed investigations into the recent gastroenteritis incidents.

1. Mandarin Orchard Hotel

A total of 315 cases were reported after people attended five separate events held at its grand ballroom between Dec. 1 and 3.

Those affected developed gastroenteritis symptoms.

Only one patient remains hospitalised, while the other 13 of the 14 patients have been discharged.

Investigations discovered that there was "improper cleaning of vomitus in the Grand Ballroom", which means that vomit matter was not cleaned up properly, as well as banquet servers working while ill.

The banquet kitchen serving the grand ballroom was suspended on Dec. 5.

Norovirus gastroenteritis has been discovered as the likely cause.

Norovirus was detected from environmental surfaces such as carpet, tables, chairs, unused table cloths, cutlery and drinking glasses, after swabs were collected from the grand ballroom.

It is a common virus that causes gastroenteritis and can spread easily from contaminated food or surfaces.

There is strong evidence of "severe contamination" of the grand ballroom from poor environmental and personal hygiene practices.

2. FoodTalks Caterer and Manufacturer

A total of 131 people, including Kindergarten 2 children and teachers, developed gastroenteritis symptoms during a pre-school day camp on Nov. 26.

This was after eating food prepared by FoodTalks Caterer and Manufacturer in Bedok North.

The exact cause could not be identified due to the short incubation period from consumption of the food to development of symptoms.

However, the predominant symptom of vomiting suggests that the outbreak was likely due to ingestion of toxins produced by bacteria in the food.

Investigations of the caterer found several hygiene lapses and poor kitchen habits.

These include the evidence of cockroach infestation and the preparation of ready-to-eat food items one to two days before consumption.

3. Tung Lok Millennium

In the third case, 190 people were reported to have developed gastroenteritis symptoms.

This was after consuming food prepared by Tung Lok Millennium at an event between Nov. 19 and 21 at the Singapore Expo.

The caterer's operating licence was suspended on Nov. 23.

An inspection found several hygiene lapses and poor kitchen habits, including lack of soap for handwashing.

Based on symptoms, the pathogen involved is unlikely to be related to any of other three outbreaks reported.

Stool samples were not available for analysis as most of the people affected had recovered by the time MOH was informed of the outbreak.

Suspension and closures still in place

NEA has to be satisfied that public health risks have been addressed before suspensions and closures of the affected places can are lifted.

The suspension of the banquet kitchen at Mandarin Orchard Hotel, the closure of its grand ballroom and the suspension of Tung Lok Millennium will remain in place.

Enforcement actions against the licensees as well as FoodTalks for the lapses will be taken by NEA.