For foods like pork liver, jellyfish, and wood ear mushrooms, "fresh" often means a potential risk of food poisoning.
"Eat it while it's fresh!" This is a common saying. Under normal circumstances, for most foods, the fresher they are, the higher their nutritional value, the better their taste, and the more appealing their color. Over time, their color, aroma, and taste deteriorate, their texture declines, nutrients are lost, harmful substances accumulate, and they may even spoil and cause food poisoning. However, for some foods, "fresh" often means a potential risk of food poisoning. Pork Liver
Some people like to eat "tender" pork liver, so when cooking, they often stir-fry it quickly just to make it tender. Little do they know that this practice poses great risks: first, the liver is the largest detoxification organ in the pig's body, where various toxic metabolic products accumulate. If it is not heated thoroughly and sufficiently, some toxic substances may remain, which can induce illness after consumption. Secondly, rapid stir-frying is difficult to kill certain pathogens or parasite eggs in the pork liver, thus damaging human health after ingestion. Fresh Jellyfish
Fresh jellyfish contains toxins and is inedible. It can only be eaten after being dehydrated several times with salt and alum to eliminate the toxins. Fresh Wood Ear Mushrooms
Fresh wood ear mushrooms contain a light-sensitive substance called porphyrin. After consumption, exposure to sunlight can cause skin itching and edema, and 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 finished products that have been sun-dried. During this process, most of the porphyrin is decomposed. Before consumption, dried mushrooms are soaked in water, which dissolves the remaining toxins, making the rehydrated dried wood ear mushrooms non-toxic. Fresh Pickled Vegetables and Fresh Sauerkraut
Fresh pickled vegetables and sauerkraut contain a considerable amount of nitrate. A few hours after salting, nitrite begins to increase significantly, peaks around 2 weeks, and then gradually decreases. Nitrite can cause symptoms of hypoxia and can also combine with secondary amines in food to form carcinogenic nitrosamines. Therefore, fresh pickled foods should not be eaten; they should be consumed after 4 weeks of pickling.