Not wasting food is a virtue. To avoid leftover food, many people save their dinner leftovers for the next day. However, not all foods can be kept overnight.
1. Can overnight tremella be eaten?
Tremella soup is a high-nutrition tonic, but after being 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 into nitrites.
When people drink this soup, nitrites naturally enter the bloodstream. The red blood cells contain hemoglobin, which can carry large amounts of oxygen for 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 blood production function!
2. Overnight tea should not be drunk
Due to the long time, most vitamins in overnight tea have been lost, and proteins, sugars, etc., in the tea will become nutrients for the growth of bacteria and molds. Therefore, it is generally believed that overnight tea should not be drunk.
3. Can't even drink overnight boiled water?
Boiling tap water for 3 to 5 minutes minimizes the content of harmful substances like nitrites and chlorides, making it most suitable for drinking.
Drink less 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 will have a significantly increased nitrite content. After 24 hours, the nitrite content in boiled water is 1.3 times that of freshly boiled water.
Chinese people have a habit of drinking boiled water. It is best to boil and drink it fresh or only drink the boiled water of the day. Also, do not drink boiled water that has been boiled for too long.
4. Can overnight eggs not be eaten?
Overnight eggs, can they be eaten?
Northerner: Yes, don't you see tea eggs sold everywhere on the street!
Southerner: No, especially for men, because it can cause a hernia and an enlarged scrotum!
Scientist: Not necessarily! If the egg is not fully cooked, the uncooked yolk, if eaten overnight, can easily breed bacteria if not stored properly, which is harmful to health, such as causing gastrointestinal discomfort, bloating, etc. However, if the food (egg) is fully cooked and stored sealed at a low temperature (generally refrigeration temperature), it can generally be stored for 48 hours without any problem.
From the scientist's advice, we can know: whether an overnight egg can be eaten depends not only on whether it has been reheated, but also on whether the egg was fully cooked the first time it was boiled. Only after the egg is fully cooked the first time can it be reheated and eaten the next day.
This is the same principle for tea eggs. Many people may not know that tea eggs are boiled twice. The first time they are boiled until cooked, the second time the eggshell is cracked, and tea and other seasonings are added and boiled again. Therefore, tea eggs are definitely cooked. Now some people like to eat half-cooked eggs (the yolk is semi-liquid), and those eggs cannot be eaten overnight, even if they are cooked a second time, do not eat them.
5. Do not eat overnight leafy vegetables!
Because some green leafy 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.
Usually, stem and leaf vegetables have the highest nitrate content, followed by gourds, with root and stem vegetables and cauliflower in the middle. Therefore, if you buy different kinds of vegetables at the same time, you should eat the stem and leaf ones first, such as cabbage, spinach, etc.
If you plan to cook more food to reheat the next day, you should try to make fewer stem and leaf vegetables and choose gourds instead.
6. Do not eat overnight home-braised and pickled foods
Braised and pickled foods are seasonal dishes liked by Shanghai citizens. Many people also like to put leftover braised and pickled foods in the refrigerator "overnight", but this practice has great food safety hazards.
To prevent food poisoning, do not eat overnight braised and pickled foods in spring and summer.
Unpackaged braised foods should be finished on the same day and not left overnight. From a food safety perspective, this is unhygienic. If possible, it is best not to eat overnight pickled foods.
Food experts remind that even food stored in the refrigerator is not absolutely "safe". Molds and psychrophilic bacteria can easily grow in the refrigerator.
7. Seafood cannot be left overnight
Foods that should not be eaten overnight include fish, seafood, green leafy vegetables, and cold dishes.
Fish and seafood, after being left overnight, easily produce protein degradation products that can damage liver and kidney function.
Green leafy vegetables contain varying amounts of nitrates. If cooked for too long or left for too long, not only will the vegetables turn yellow and taste bad, but the nitrates will also be reduced by bacteria into toxic nitrites, which are carcinogenic.
Cold dishes are more contaminated during processing. Even after refrigeration, they are very likely to have spoiled overnight and should be made and eaten fresh.
8. What to do with overnight soup?
Cantonese people love to make soups. If there is leftover soup, they put it in the refrigerator and reheat it the next day. Is this overnight soup good for your health?
Healthy way to eat:
The best way to store soup is not to add seasonings like salt to the base. After cooking the soup, use a clean spoon to scoop out the portion for the day. For the leftover soup, it is best to store it in a crock pot in the refrigerator.
This is because storing leftover soup in an aluminum or stainless steel pot for a long time can easily cause chemical reactions. It should be stored in glass or ceramic containers.