MOH confirms link between Chinese-style raw fish and GBS bacteria

SINGAPORE - Food stalls are no longer allowed to sell Chinese-style raw fish dishes unless they comply with guidelines set out by the National Environment Agency (NEA).

The guidelines include purchasing from suppliers who can show the quality of the fish - by providing a valid health certificate, for instance - and ensuring that the fish are kept at below five degrees Celsius during transportation and chilling.

This comes as the Ministry of Health (MOH) confirmed an association between the consumption of Chinese-style raw fish, such as song fish (Asian Bighead Carp) and toman fish (Snakehead fish), and Type III Group B Streptococcus (GBS) disease, specifically due to Sequence Type (ST) 283. The ministry was investigating the spike in the number of GBS infections reported here since the middle of this year.

Most recently, a 52-year-old man fell into a coma days after consuming a bowl of yusheng-style raw fish porridge on Nov 15.

Food handlers are unlikely to be the source of the bacteria causing GBS infections, the NEA, MOH and Agri-Food & Veterinary Authority of Singapore (AVA) said in a joint statement today.

"The stool samples of 82 food handlers and fishmongers from retail food establishments, market stalls, and wholesalers were tested. None of them carried the Type III GBS ST283 strain," the statement said.

Between August and October, the AVA and NEA tested fish samples from retail food establishments, wet markets, fresh produce section of supermarkets and fishery ports. GBS was detected in 20.1 per cent of these samples, and 4.1 per cent were confirmed positive for Type III GBS ST283. The contamination of the fish could have occurred along the food supply chain, the NEA, MOH and AVA said.

They added that the number of GBS cases reported has decreased to the usual baseline of fewer than five per week and continued to remain low since mid-July, when the NEA issued an advisory to food stalls to temporarily stop selling Chinese-style raw fish dishes. The cause of these baseline infections remains unknown.

Members of the public are advised to purchase Chinese-style raw fish from establishments that have separate processes to handle these raw fish from other raw food meant for cooking.

Most fish sold at Singapore's general markets and fishery ports are intended for cooking, and should not be eaten raw. Proper cooking would ensure that naturally-occurring bacteria or parasites are killed. Procuring fish that are intended for raw consumption reduces the risk of foodborne illness, the authorities said. Such fish are typically bred or harvested from cleaner waters, and are stored and distributed according to appropriate cold chain management practices.

huizhen@sph.com.sg