Can you eat overnight food? Is overnight food edible? This has always been a concern for everyone. So, which overnight foods should absolutely not be eaten? Let's learn about the eight types of overnight food that should never be consumed.
1. Overnight Tremella (wood ear mushroom) should not be eaten
Tremella soup is a high-nutritional tonic, but once it's left overnight, its nutritional value decreases and harmful substances are produced. This is because both indoor-cultivated and wood-cultivated tremella contain a high amount of nitrates. After being cooked, if left for a long time, bacteria will break down the nitrates, reducing them to nitrites. When people drink this soup, nitrites naturally enter the bloodstream. The red blood cells contain hemoglobin, which can carry large amounts of oxygen to meet the body's needs.
However, nitrites have the opposite effect, oxidizing the body's normal hemoglobin into methemoglobin, which loses its ability to carry oxygen, causing the body to lack normal hematopoietic function!
2. Overnight leafy greens should not be eaten
Some leafy green vegetables contain a high amount of nitrates. If cooked and left for too long, bacteria will break down the nitrates into nitrites, which are carcinogenic and cannot be removed by reheating. Generally, stem and leaf vegetables have the highest nitrate content, followed by root and stem vegetables, then flower and head vegetables, and gourds have the lowest.
Therefore, if you buy different types of vegetables at the same time, you should eat the stem and leaf varieties first, such as Chinese cabbage and spinach. If you plan to cook extra food to reheat the next day, try to minimize stem and leaf vegetables and choose gourds instead.
3. Homemade braised and marinated foods should not be eaten overnight
Braised and marinated foods are popular seasonal dishes in Shanghai. Many people like to store leftover braised and marinated foods in the refrigerator "overnight," but this practice poses significant food safety risks. To prevent food poisoning, avoid eating leftover braised and marinated foods overnight during spring and summer. Bulk braised foods should be finished on the same day and not left overnight. From a food safety perspective, this is unhygienic. If possible, it's best not to eat leftover marinated foods. Food experts remind us that even food stored in the refrigerator is not absolutely "safe." The refrigerator can easily grow mold and other cold-tolerant bacteria.
4. Seafood should not be eaten overnight
Foods that should not be eaten overnight include fish, seafood, leafy greens, and cold salads. Fish and seafood can produce protein degradation products overnight, which can damage liver and kidney function. Leafy greens contain varying amounts of nitrates. If overcooked or left for too long, the vegetables will turn yellow and spoil, and the nitrates will be converted by bacteria into toxic nitrites, which are carcinogenic. Cold salads are more susceptible to contamination during preparation, and even after refrigeration, they are likely to have spoiled overnight. They should be made and eaten fresh.
5. Overnight soup is best not to be drunk
People in Guangdong love to make soups. Leftover soup is often put in the refrigerator and reheated the next day. Is this overnight soup good for your health?
Healthy way to store: The best way to preserve soup is not to add salt or other seasonings to the base. After cooking the soup, use a clean spoon to scoop out the portion for the day. For the leftover soup, it's best to store it in a clay pot in the refrigerator. This is because storing leftover soup in aluminum or stainless steel pots for a long time can cause chemical reactions. It should be stored in glass or ceramic containers.
6. Overnight tea should not be drunk
Because overnight tea has been left for too long, most of its vitamins are lost, and the proteins and sugars in the tea become nutrients for the growth of bacteria and mold. Therefore, it is generally believed that overnight tea should not be drunk!
7. Overnight undercooked eggs should not be eaten
Can you eat overnight eggs? Northerner: Yes, don't you see tea eggs sold everywhere! Southerner: No, especially for men, because it can cause hernias and swollen testicles! Scientist: It depends! If the egg is not fully cooked, the uncooked yolk, if eaten overnight, can easily breed bacteria if not stored properly, which can be harmful to health, causing issues like indigestion and bloating.
However, if the food (egg) is fully cooked and properly sealed and stored at a low temperature (generally refrigeration temperature), it can usually be safely stored for up to 48 hours.
From the scientist's advice, we know that whether an overnight egg is edible depends not just on whether it is reheated, but on whether it was fully cooked the first time it was boiled. Only after being fully cooked initially can an egg be safely reheated and eaten the next day. Tea eggs follow this principle. Many people may not know that tea eggs are boiled twice: the first time to cook them through, and the second time after cracking the shells and adding tea and other ingredients. So, tea eggs are definitely fully cooked. Now, some people like to eat half-cooked eggs (with a runny yolk). Those eggs should not be eaten overnight, even if reheated, the second time.
8. Overnight boiled water should be avoided as much as possible
Boiling tap water for 3-5 minutes minimizes the content of harmful substances like nitrites and chlorides, making it most suitable for drinking.
Avoid drinking overnight boiled water: Nitrites can form carcinogenic nitrosamines in the body. Experts have found that the nitrite content in boiled water is higher than in raw water. Moreover, repeatedly boiling water for too long or water that has been boiled for more than 24 hours shows a significant increase in nitrite content. After 24 hours, the nitrite content in boiled water is 1.3 times higher than when it was first boiled. Chinese people have a habit of drinking boiled water. It is best to boil and drink it fresh or only drink water from the same day. Also, avoid drinking water that has been boiled for too long.