Nine members of same family die from eating frozen noodles after being poisoned by deadly toxin

The meal is a popular Chinese delicacy in the region and was served for breakfast for the gathering of 12 on the morning of October 5, local media reports.

However, the noodles had spoiled from being frozen and a high concentration of bongkrek acid - a deadly respiratory toxin produced by the bacterium pseudomonas cocovenenans - had formed unbeknown to the family.

The family began to feel unwell within hours of consuming the dish.

By October 12, eight family members were dead.

The final surviving adult, a mother surnamed Li, died a week later on Monday October 18.

Three of the twelve family members were spared from the sickness after three children refused to eat the dish, complaining about the taste.

Chinese authorities released a statement saying nine people had died of food poisoning after finding "a high concentration of bongkrekic acid" in the noodle soup.

Local authorities cited information released by the Food Division of the Heilongjiang Provincial Health and Health Commission, noting the toxin was also discovered in the gastric fluid of the adults.

Gao Fei, director of food safety at the Heilongjiang Centre for Disease Control and Prevention, said the results can often be fatal.

“It can cause serious damage to many human organs including the liver, kidneys, heart, and brain,” Mr Gao told China News Service.

“Currently, there is no specific antidote. Once poisoned, the fatality rate can be as high as 40 per cent to 100 per cent.”

On Monday, the National Health Commission reminded the public to be cautious about eating fermented rice and noodles that have been fermented for a long time.

The noodles are a traditional and popular choice in Northeast China, made with corn water mill and fermented.

"The fermented rice noodles are generally made by soaking corn, sorghum rice and other grains in water, and after natural fermentation for more than ten days, wet ground into a paste-like water noodles, and then filtered water to air dry," food science author Qian Cheng explained.

However, the fermentation process produces less acid and is damp before air-drying, which meets the conditions for large numbers of bacteria to multiply, Cheng said.

The symptoms of bongkrek poisoning typically begin within a few hours of eating contaminated food, and include stomach pain, sweating, general weakness and eventual coma.

Death can come as swiftly as just 24 hours.

Bongkrek acid has been implicated in outbreaks of foodborne illness involving coconut and corn-based products in Indonesia and China.

The acid cannot be removed even if thoroughly cooked and boiled and there is no medicine or cure available to treat such cases of poisoning, Global Times reported.