The authorities are investigating two welfare homes after 59 people fell ill from eating food prepared in their kitchen.
The homes in Pelangi Village, a social welfare complex in Buangkok, have been ordered to stop using the kitchen.
The Health Ministry and Singapore Food Agency said in a joint statement yesterday that as of Monday noon, Angsana Home had 22 cases of gastroenteritis and Banyan Home, 37.
All 59 had symptoms from May 14 to May 18, the statement added.
Eleven were hospitalised. Three have since been discharged while the rest are in stable condition.
Said the statement: "Those affected had consumed food from the homes' in-house kitchen, which has been instructed to cease operations while the investigation is ongoing."
Gastroenteritis can lead to diarrhoea or vomiting, and is caused by viruses, bacteria or bacterial toxins.
It can be a result of consuming contaminated food, having direct contact with infected people, or touching contaminated surfaces or objects and then touching the mouth without washing one's hands.
Those affected will need to stay hydrated by drinking plenty of water and see a doctor, if necessary.
When contacted, both Banyan Home and Angsana Home declined to comment.
This latest case follows several food poisoning incidents last month.
On April 4, more than 20 students staying at Ridge View residential college at the National University of Singapore fell ill after eating food at its dining hall. Eight days later, five became ill after a meal at the university's residential hall Prince George's Park House.
On April 25, it was reported that 230 Zhenghua Primary School pupils had developed gastroenteritis over a week.
Before that, there were a string of food poisoning cases, starting in March, at 13 PCF Sparkletots pre-schools and P.L.A.N Student Care Centre. They involved nearly 260 young children and staff who ate food prepared by an outside caterer.
Kate's Catering was subsequently suspended and the suspension was lifted last Friday.