Hawkers have been told to stop selling Chinese-style raw fish dishes - including raw fish porridge - immediately, unless they can show that the fish are from safe suppliers, the authorities said yesterday.
Investigations have confirmed a link between such dishes and what appears to be a particularly aggressive strain of Group B Streptococcus bacteria (GBS) - Sequence Type (ST) 283 - that has made some people here seriously ill and could have killed one person.
The Ministry of Health (MOH) told The Straits Times that it has been notified of 355 cases of GBS infection this year, of which around 150 belonged to the ST283 strain.
Two infected patients died, MOH said. One death is being investigated, while another is not linked to the outbreak.
"Following the investigations, the National Environment Agency advises that all retail food establishments that sell ready-to-eat raw fish dishes are to source raw fish from suppliers that adopt proper cold chain management and hygienic handling practices of the fish," said the agency, the Agri-Food and Veterinary Authority and MOH in a statement.
Food handlers and fishmongers tested negative for the virulent strain, but fish were a likely source, investigations revealed.
Between August and last month, nearly 400 fish samples across the supply chain, from fishery ports to wet markets and food outlets, were tested. GBS was detected in a fifth of the samples, and 4.1 per cent of total samples tested positive for ST283.
Song fish (Asian bighead carp), toman fish (snakehead) and tilapia, all freshwater species, were the ones which tested positive for ST283.
The authorities stressed that most fish sold in wet markets or at fishery ports are intended for cooking and should not be eaten raw, as they could carry a number of parasites or bacteria.