Eight members of the same family in northeastern China’s Heilongjiang province have died, with another still receiving medical treatment, after they consumed a toxic homemade corn noodle dish.

The poisoning was caused by bongkrekic acid, a respiratory toxin produced by a bacterium found in fermented food, domestic media reported Tuesday, citing the provincial health commission. The nine family members in the city of Jixi had consumed suantangzi, a soupy noodle dish made from fermented corn flour, on Oct. 5, though it’s unclear when they were hospitalized.

The dish’s “ingredients” were homemade and had been frozen for nearly a year, according to the media report. Local police have ruled out the possibility of intentional poisoning.

Gao Fei, director of food safety at the Heilongjiang Center for Disease Control and Prevention, told the state-run China News Service that bongkrekic acid is resistant to high temperatures, and its toxicity cannot be removed even if the food is boiled in water or steamed in a pressure cooker.

“It can cause serious damage to many human organs including the liver, kidneys, heart, and brain,” he said. “Currently, there is no specific antidote. Once poisoned, the fatality rate can be as high as 40%-100%.”

This is not the first bongkrekic acid-related food poisoning case this year. In July, one person died in the southern Guangdong province and 10 others were sickened, with vomiting and diarrhea, after eating rice noodles found to have the respiratory toxin.

Editor: Bibek Bhandari.

(Header image: A man eats “suantangzi” at a restaurant in Dandong, Liaoning province, Jan. 21, 2018. People Visual)