Two food caterers had their grade for hygiene lowered to "C" recently after 45 people fell ill with food poisoning in separate incidents last December and March this year.
Nearly half that number ate at a student dining hall in National Junior College's (NJC) boarding school.
Notices on the Singapore Food Agency (SFA) website this week showed that 21 people reported symptoms related to gastroenteritis on March 9 after consuming food provided by Pro*3 Institutional Catering, which offers staff cafeteria and dining hall services. The incident occurred at the NJC Boarding School at 41 Hillcrest Road.
In the second case, which occurred on Dec 18 last year, 24 people suffered similar symptoms after eating food supplied by Chilli Api Catering, which is located at Shimei East Kitchen in Bedok North Street 5.
Chilli Api Catering provides halal buffet sets for corporate and private events and specialises in Peranakan cuisine.
The symptoms of gastroenteritis include diarrhoea and vomiting.
SFA investigated both incidents and decided on downgrading the food hygiene rating of the two caterers. A check on the SFA website showed that both caterers were graded "A" previously.
Pro*3 Institutional Catering's new grade took effect on Monday. For Chilli Api Catering, it took effect the next day.
SFA said that the food caterers' premises would be under surveillance until the next review of their food hygiene in 12 months' time.
Earlier this month, Delizio Catering had its food hygiene grade cut to "C" from its previous "A" grade, after 18 people reported having gastroenteritis symptoms.
Those affected attended a Christmas party on Dec 12 for one of Delizio Catering's customers.
Last month, food caterer Elsie's Kitchen also had its food hygiene grade downgraded to "C" after 52 people fell ill after consuming its food in February.
And, in March, a gastroenteritis outbreak affected 13 PCF Sparkletots pre-schools and P.L.A.N Student Care Centre. There were about 260 cases.
The source of food poisoning was traced to the consumption of food prepared at Kate's Catering, and its operating licence was suspended for a total of 52 days.