For foods like pork liver, jellyfish, and wood ear mushrooms, "freshness" often implies potential risks of food poisoning.
"Eat it while it's fresh!" 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 worsens, nutrients are lost, harmful substances accumulate, and they may even spoil and cause food poisoning. However, for some foods, "freshness" often implies potential risks of food poisoning. Fresh Pork Liver
Some people prefer "tender" pork liver and, to achieve this tenderness, often cook it quickly and eat it. Little do they know that this practice carries significant risks: first, the liver is the largest detoxification organ in a pig's body, where various toxic metabolic products accumulate. If not heated thoroughly and sufficiently, some toxic substances may remain, which can induce illness after consumption. Secondly, rapid cooking may not kill certain pathogenic bacteria or parasite eggs in the pork liver, thereby harming 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 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 mucous membrane of the throat, it can cause difficulty in breathing. Dried wood ear mushrooms are products that have been sun-dried. During this process, most of the porphyrin is decomposed. Before consumption, the dried mushrooms are soaked in water, which dissolves the remaining toxins, making the rehydrated mushrooms non-toxic.
Fresh Pickled Vegetables and Fresh Sauerkraut
Fresh pickled vegetables and sauerkraut contain a significant amount of nitrate. A few hours after salting, the nitrite content begins to increase noticeably, peaks around 2 weeks, and then gradually declines. Nitrites can cause symptoms of oxygen deprivation and can combine with secondary amines in food to form carcinogenic nitrosamines. Therefore, fresh pickled foods should not be eaten; they should be consumed after being pickled for 4 weeks.