Jellyfish
Fresh jellyfish contains a lot of water, has a thicker body, and also contains toxins. Only after being salted and alum-pickled three times (commonly known as "three-alum") to dehydrate it three times can the toxins be completely expelled with the water. After the three-alum process, the jellyfish is light red or light yellow, with uniform thickness and toughness, and no water can be squeezed out even with force. Only this kind of jellyfish is edible. When traveling to jellyfish-producing areas, you may encounter vendors selling untreated jellyfish or jellyfish that has only been salted once or twice. You must absolutely not taste or buy it.
Fresh Daylilies
Also known as golden needles, the unprocessed fresh product contains colchicine. Colchicine itself is non-toxic, but after being eaten, it is oxidized in the body into highly toxic colchicine dioxide. According to experimental calculations, as little as 3 milligrams of colchicine is enough to cause nausea, vomiting, headache, and abdominal pain. A larger dose can lead to hematuria or hematochezia, and 20 milligrams can be fatal. Dried daylilies are steamed and processed, during which the colchicine is leached out, making them non-toxic.
Fresh Wood Ear Mushrooms
They contain a photosensitive substance called porphyrin. After consumption, exposure to sunlight can cause skin itching and edema. In severe cases, it can lead to skin necrosis. If edema occurs in the pharyngeal mucosa, it can cause difficulty in breathing. Dried wood ear mushrooms are the final product after being sun-dried. During the sun-drying process, most of the porphyrin is decomposed. Before consumption, the dried mushrooms are soaked in water, and any remaining toxins are dissolved into the water, making the rehydrated dried mushrooms non-toxic.
Fresh Pickles
Fresh vegetables contain a certain amount of non-toxic nitrate. During the pickling process, it is reduced into toxic nitrite. Generally, nitrite begins to increase significantly 4 hours after pickling, peaks between 14 and 20 days, and then gradually decreases. Therefore, you should either eat pickles within 4 hours of being made, or eat pickles that have been pickled for more than 30 days. Nitrite can cause human poisoning and can also combine with secondary amines in food to form carcinogenic nitrosamines.
Bottled Water
Commercially bottled water, whether it's distilled water, reverse osmosis water, mineral water, or other purified water, is mostly treated with ozone as a final disinfection before being bottled. Therefore, freshly filled bottled water will contain a relatively high concentration of ozone. For humans, ozone is a toxic substance. If you drink it while it's fresh, you will undoubtedly ingest the toxin along with it. If you let the bottled water sit for another 1 to 2 days, the ozone will naturally dissipate, and then you can drink it without worrying about ingesting poison. According to regulations, bottled water must pass inspection before it can leave the factory, and this process takes 48 hours. Therefore, drinking bottled water that has been inspected and released from the factory in accordance with regulations is safe.