If it is raw, you can eat untreated white radish. If fried, cooked white radish will produce nitrite overnight, which is harmful to human body. You'd better not eat it.

Why is it best not to eat overnight dishes?

From the perspective of food science, staying overnight is not a problem. The essence of the problem is what happens to cooked vegetables during storage. We are worried that nitrate in vegetables will be converted into nitrite. This transformation process can be realized by the original reductases in vegetables, but in the process of cooking, these enzymes lose their activity and this road is cut off. Another way is the role of bacteria. Originally, the vegetables were cooked and the bacteria in them were almost killed. But in the process of eating, some bacteria will enter the leftovers on chopsticks; During the preservation process, some bacteria in the air may also enter. Cooked vegetables are more suitable for bacterial growth. Under appropriate conditions, they will grow in large quantities, and nitrate may be converted into nitrite during the growth process.

Excessive use or misuse of excessive nitrite in some processed sauced meat and stews will lead to food poisoning and death. In addition to its own toxicity, nitrite reacts with protein decomposition products under acidic conditions, easily producing nitrosamine carcinogens, which has an indirect carcinogenic effect, especially for gastric cancer, and is an important carcinogenic factor that cannot be ignored by modern people.

Eight kinds of overnight food that must not be eaten.

1, no overnight tea.

After staying overnight for a long time, most of the vitamins are lost, and the protein and sugar in the tea soup will become nutrients for bacteria and mold. So people usually think that overnight tea can't be drunk.

2. Can tremella be eaten overnight?

Auricularia auricula soup is an advanced nutritional supplement, but after a night, the nutritional components will be reduced and harmful components will be produced. Because both the tremella cultivated indoors and the tremella cultivated in the wild of basswood contain more nitrate, if cooked for a long time, the nitrate will be reduced to nitrite under the decomposition of bacteria. When people drink this soup, nitrous acid naturally enters the blood circulation. Red blood cells in the blood contain hemoglobin, which can carry a lot of oxygen for the body's needs.

Nitrite, on the other hand, has the opposite effect, oxidizing normal hemoglobin in human body into methemoglobin, losing its oxygen-carrying ability, leading to the loss of normal hematopoietic function in human body!

You can't drink boiled water overnight.

Boil tap water for 3 ~ 5 minutes, the content of nitrite, chloride and other harmful substances is the lowest, which is most suitable for people to drink. Drink less boiled water overnight: Nitrite can form carcinogenic nitrosamines in human body. Some experts have found that the nitrite content in boiled water is higher than that in raw water. In addition, if the boiling time is too long or repeated for more than 24 hours, the nitrite content will increase obviously. After standing in boiling water for 24 hours, the nitrite content is 1, which is three times that of when it was just boiled. China residents have the habit of drinking boiled water, and it is best to burn it now or only drink the boiled water of the day. Don't drink boiled water for too long.

4. eggs can't be eaten overnight

Not necessarily, because if the eggs are not completely cooked and the immature yolk is eaten overnight, nutritious things will easily breed bacteria and be harmful to the body, such as gastrointestinal discomfort and flatulence, if they are not properly preserved. However, if the food (eggs) is cooked and properly sealed at low temperature (usually refrigeration temperature), it can generally be preserved for 48 hours. From the tips of scientists, we can know that whether eggs can be eaten overnight depends not only on whether they are heated, but also on whether they are cooked for the first time. Only after the first boiled egg is cooked, it is no problem to cook it overnight. This is also the truth of tea eggs. Maybe you don't know that tea eggs are cooked twice. Boil it for the first time, crush it for the second time, and then cook it with tea and other auxiliary materials. So tea eggs must be boiled. Now some people like to eat soft-boiled eggs. That kind of egg can't be eaten overnight. Don't eat it even if it is cooked for the second time.

5. Don't eat leafy vegetables overnight.

Because some green leafy vegetables contain more nitrate, if they are left for too long after cooking, nitrate will be reduced to nitrite under the decomposition of bacteria, which is carcinogenic and cannot be removed by heating. Usually, the nitrate content of stem and leaf vegetables is the highest, melon vegetables are slightly lower, and roots and cauliflower are in the middle. Therefore, if you buy different kinds of vegetables at the same time, you should eat stems and leaves first, such as Chinese cabbage and spinach. If you are going to cook more vegetables and eat them hot the next day, try to make fewer stem and leaf vegetables and choose melons.

6. Don't eat bad food at home overnight.

Pot-stewed and rotten vegetables are both popular seasonal dishes in Shanghai. Many citizens also like to put the leftover stewed and spoiled food in the refrigerator for the night, but this practice has great food safety hazards. To prevent food poisoning, don't eat inferior goods braised overnight in spring and summer. Bulk braised pork should be eaten on the same day, not overnight. From the perspective of food safety, this is unsanitary. If possible, it is best not to eat bad goods overnight. Food experts warn that even the food in the refrigerator is not absolutely "safe". Refrigerators are prone to mold and psychrophilic bacteria.

Healthy eating style

First, vegetables suitable for raw food

Carrots, white radishes, water radishes, tomatoes, cucumbers, sweet peppers, Chinese cabbage hearts, purple cabbage, etc. It is best to choose pollution-free green vegetables or organic vegetables for raw food. The methods of eating raw vegetables include homemade vegetable juice, adding cold dishes such as vinegar, salt and olive oil to fresh vegetables, and cutting into pieces and dipping them in sauce.

Second, vegetables that need to be blanched.

Cruciferae vegetables, such as broccoli and cauliflower, taste better after blanching, are rich in cellulose and are easier to digest; Spinach, bamboo shoots, water bamboo and other vegetables containing more oxalic acid are also best blanched, because oxalic acid combines with calcium in the intestine to form calcium oxalate, which interferes with the body's absorption of calcium; Mustard vegetables, such as kohlrabi, contain glucosinolates, which are hydrolyzed after boiling to produce volatile mustard oil, which tastes better and can promote digestion and absorption. Blanching wild vegetables such as purslane can completely remove dust and insects and prevent allergies. There are lettuce, water chestnut and so on. It's best to peel, wash and scald with boiling water before eating.

Third, vegetables that can only be eaten after cooking.

1. Vegetables containing starch, such as potatoes, taro, yam, etc. Be sure to cook it, otherwise the starch granules inside will not be broken and the human body cannot digest it;

2, lentils and green beans containing a lot of saponins and hemagglutinin must be cooked and discolored when eating;

3, bean sprouts must be cooked and eaten, whether it is cold or fried.

Fresh yellow flowers and fungus can't be eaten.

Fresh fungus and fresh day lily contain toxins, so don't eat them. When eating dried auricularia auricula, it should be soaked in warm water before cooking, and the part that is still tight after soaking should not be eaten; It is better to soak dried yellow flowers in cold water.

Fourth, the combination of raw and cooked is the most beneficial.

Eating raw and cooked vegetables together is more beneficial to your health. If there are many kinds of radish, it is better to eat it raw, juicy and less spicy, but it belongs to cold food, and it is better for people with yin deficiency to eat it cooked. Some foods have different nutrients when eaten raw or cooked. For example, tomatoes contain lycopene, which can reduce the risk of prostate cancer and liver cancer. If you want to eat it, you should eat it cooked. But if you want to take vitamin C, the effect will be better if you eat it raw, because vitamin C is easy to be lost during cooking.

1, leafy vegetables

The vegetables ranked first include lettuce, which westerners often eat. It is dangerous, mainly because it is not properly cleaned. Westerners often eat vegetables in the form of lettuce salad. If it is not clean enough, vegetables are easily contaminated by this kind of E.coli..

Green leafy vegetables may be contaminated by contact with wild animals, farm manure and unclean water, or by poor sanitary conditions when farmers pick them, and then continue to breed germs. Cleaning after picking can not guarantee food safety.

Step 2: eggs

Salmonella, an egg food, can live in the intestines of animals and spread to eggs through feces. Some salmonella can infect hens' ovaries, so that eggs can be infected before the eggshells grow.

3. Tuna

The symptoms caused by tuna are usually mackerel poisoning. Tuna will rot quickly after being caught. If the storage temperature exceeds 15.6 degrees Celsius, natural toxins will be released. This toxin cannot be decomposed by cooking, refrigeration, smoking, processing or canning.

4.oysters

Oysters are usually caused by Norwalk virus or Vibrio, and the former may come from polluted waters. Raw or undercooked oysters can cause gastroenteritis. Vibrio is similar to cholera and more dangerous.

5. potatoes

Potatoes are usually cooked aseptically, but potato dishes often have many ingredients, some of which may be problematic. Salmonella is the most common, followed by Escherichia coli.

6.cheese

Cheese Some Latin American cheeses may be made from unsterilized milk. Soft cheese may contain listeria, so pregnant women must be careful before eating it, otherwise it will lead to miscarriage.

7.ice cream

Ice cream Soft ice cream also contains Listeria. This kind of bacteria can survive on the metal surface and stay in the ice cream machine, polluting a lot of ice cream.

8. tomatoes

Tomatoes are usually caused by salmonella. This fungus enters tomatoes through roots or flowers, so tomatoes cannot be eaten raw.

9.bean sprouts

The seeds of sprouts may be polluted when planted or stored, and the warm and humid environment needed for their growth is likely to lead to a large number of bacteria.

10, Berry

Berries containing cyclosporine can parasitize the intestines, causing severe diarrhea, dehydration and stomach cramps. Patients must be injected with antibiotics, so they must seek medical treatment.

How to deal with overnight vegetables scientifically to make them difficult to deteriorate

First of all, inedible food should be stored at room temperature for no more than two hours; Secondly, the leftovers should be classified and packaged. If the leftovers are simply put in large containers, the food will take a long time to cool, which will increase the risk of bacterial growth.

Experts suggest that the best way is to divide the food into several portions and put them in shallow containers to speed up the heat dissipation of the food. In addition, cooked food should not be kept in the refrigerator for more than 3 days at most. The food stored in the refrigerator must be heated to at least 75℃ before eating, and the food with more water must be cooked to the boiling point.