What is already known on this topic? Poisoning incidents caused by bongkrekic acid (BA), one of the metabolites of Burkholderia gladioli pathovar cocovenenans (B. cocovenenans), have been reported in Indonesia, Mozambique, and China. The reported case fatality rates averaged 60%, 32%, and 26.5%, respectively. In China, B. cocovenenans is often called Pseudomonas cocovenenans subsp. farinofermentans. What is added by this report? In October 2020, 9 persons in Jidong County, Heilongjiang Province died after consuming a homemade fermented corn flour product - sour soup - with a case fatality rate of 100%. BA was detected in both food samples and biological samples with a content of 330 mg/kg and 3 mg/L, respectively. The doses of BA consumed by the cases were approximately 22-33 times the lethal dose in human. What are the implications for public health practice? The consumption of fermented corn flour products, deteriorated fresh tremella, or black fungus and metamorphic starch products may cause BA poisoning. Health education should be strengthened so that homemade-starch-fermented food should be avoided and foods that have been kept for a long time should not be consumed. Meanwhile, training and emergency capacity building for primary healthcare workers should be strengthened to provide timely diagnosis and response.