Auricularia auricula is a "regular customer on the tip of the tongue" of Chinese people. It can hold cold dishes, hot frying and hot pot cooking. However, in recent years, we often see the news of edible black fungus poisoning. What on earth made the delicious black fungus become a deadly "poisonous fungus"? News review The reporter found that since 2010, Shaanxi, Zhejiang, Hunan, Anhui and Liaoning have all seen poisoning cases of multiple organ damage caused by eating black fungus soaked for a long time. In April this year, Ms. Wang, from Hangzhou, Zhejiang Province, ate black fungus that had been soaked for two days. Soon, she had abdominal pain, diarrhea, high fever, low blood, cold and wet limbs, and yellow staining of the skin and sclera. After the hospital inspection, it was found that Ms. Wang's organs were damaged, her liver and kidney functions deteriorated, and she had shock symptoms immediately. After timely symptomatic rescue, he was out of danger of life. Scientifically dispel the doubt that the fungus produced pathogenic bacteria after long-term immersion "First of all, it must be affirmed that the fungus itself is non-toxic." Experts from the Food School of Jiangnan University emphasized that Auricularia auricula contains rich nutrients, including protein, microelements, carbohydrates, fats and other substances necessary for the human body. However, the black fungus we bought in the market is generally the product of sun drying. Therefore, it is necessary to foam hair before making. The outer skin of Auricularia auricula has a layer of glial nutrients. During the foaming process, the outer skin will split, and the nutrients contained in it will gradually penetrate into the water. This is equivalent to turning the water soaked in black fungus into "nutrient water" and becoming a "hotbed" for bacteria and mold to breed. "In the environment where the black fungus soaked for a long time is located, there is a pathogenic bacterium called Pseudomonas coconuts." Zhang Yi, associate professor of the School of Food, Jiangnan University, told the reporter that Pseudomonas coconuts is a kind of bacteria that widely exists in nature. If the black fungus is not stored and processed properly during the planting and transportation process, it may be contaminated by bacteria. And this kind of fungus will produce a highly toxic toxin, which is "rice yeast acid". The clinical symptoms of rice yeast acidosis are nausea, vomiting, abdominal pain, abdominal distension, etc. In severe cases, multiple organ damage may occur, and even death may occur. It is worth noting that because of its high heat resistance, even cooking at 100 ℃ can not damage the toxicity of rice yeast acid. The "fatal toxin" was detected after 16 hours of immersion. Here, we noticed a key word: long immersion. How long will the black fungus become "poisonous"? This time, we walked into the microbiological laboratory of Jiangnan University. Pseudomonas cocoanut is a facultative anaerobic bacteria, which is easy to grow on the surface of food. The most suitable growth temperature is 37 ℃, and the most suitable temperature for producing zymosic acid is 26 ℃, within the range of pH 5-7. In the laboratory, the experimental personnel simulated the most suitable environment for the growth of Pseudomonas coconuts and the production of zymosic acid, soaked and stored the auricularia auricula samples, detected whether zymosic acid was produced in the samples, and verified the correlation between auricularia auricula bubble hair, storage conditions and the production of zymosic acid, and the safety of eating. The experimenters from the "Green Bud Food Cultivation" team of the School of Food of Jiangnan University bought black agaric in the supermarket and divided four equal portions of dry agaric,