The key to whether overnight fungus will kill you is not whether it is overnight or the length of time it has been stored, but whether it has deteriorated during the storage process. If the fungus deteriorates, it is likely to cause adverse effects on the body and may lead to death by poisoning, but overnight fungus that has not deteriorated is not harmful. The deteriorated fungus is susceptible to contamination by Pseudomonas aeruginosa, which can cause serious toxic reactions and even death. The main target organs for the action of rice fungal acid are human liver and kidney as well as brain, and the poisoned person shows dizziness, palpitations, vomiting, diarrhea, etc. Organ failure can occur rapidly and the mortality rate is high, more than 40%. In addition to this, there may be other bacterial infections such as Aspergillus flavus, which can produce toxic substances such as aflatoxin and cause organ damage such as liver and gastrointestinal tract. Therefore, there is a greater risk of consuming fungus after it has deteriorated, not without the possibility of causing death. However, the overall likelihood of overnight fungus causing acidosis from rice fermentation bacteria is not high, and the risk can usually be reduced if stored properly to prevent deterioration. If too much fungus is soaked at one time, it is recommended that the water used to soak the fungus be replaced and stored in the refrigerator with plastic wrap to help avoid spoilage or harmful substances, and that the fungus be washed after removal the next day so that it can generally be cooked and eaten. If you can’t tell if overnight fungus has deteriorated, you can smell it or take a little bit of it and taste it to see if there is any odor, and if you find that the taste and smell have changed, it is recommended that you do not eat it. It is generally recommended to consume fresh food and try not to eat spoiled food.