Can I eat overnight dishes?
I believe three aunts at home said that the nitrite content of this overnight dish is easy to cause cancer. Granny Liu said that overnight dishes can be eaten, and she has been eating them for many years. Eight big moms said that eating is not clean and not sick, and who to listen to is very entangled.
In order to find out what overnight dishes are and how harmful they are, researchers in a laboratory of Zhejiang University decided to study them well. They invited a restaurant chef with guaranteed hygiene to cook four classic home-cooked dishes: fried vegetables, fried eggs with leeks, braised pork and braised crucian carp. They carefully studied the hygiene problems of overnight dishes, a circle of friends who had been discussing endlessly.
Next, let's take a closer look at how long it will take before it can be called an inedible overnight dish!
First of all, the four dishes are divided into four parts immediately after being cooked, put into a disposable lunch box with plastic wrap, and then put into a refrigerator at 4℃ for preservation.
After standing for half an hour.
Half an hour after cooking, the test results of stir-fried dishes, scrambled eggs with leeks and braised pork showed that the nitrite content did not exceed the maximum limit of China's "Limits of Pollutants in Food". However, the nitrite content in braised pork is higher than that in fried eggs and vegetables with leeks.
The experimenter said that meat dishes generally add more seasonings than vegetables, and the seasonings themselves contain nitrate, which is converted into nitrite by microorganisms, resulting in higher nitrite content in braised pork.
Leftovers for half an hour:
Although it was only half an hour, the meat was still warm and was sentenced to the fate of "leftovers". If you want to eat healthy, you might as well cook the meat lightly, and be careful not to cook too much meat at once!
Leave for six hours
Six hours later, it's almost the time interval between lunch and dinner. It is common for many elderly people or families with two employees to eat cooked dishes at noon and at night on rest days.
The experimenter opened the refrigerator, took out the stir-fried dishes marked "6 hours", scrambled eggs with leeks, braised pork and braised crucian carp, then put them in the microwave oven and heated them with medium and low fire for 1 min. These dishes still look fresh after being taken out of the microwave oven.
The nitrite content of these dishes was determined by the experimenter. The results showed that after 6 hours, the nitrite content in the leftovers increased, the stir-fried vegetables increased by 16%, the scrambled eggs with leeks increased by 6%, and the braised pork increased by 70%. Among them, the nitrite content in braised pork exceeds the limit standard of "3mg/kg meat" in the National Limit of Pollutants in Food.
Six hours leftovers summary:
Braised pork has become a leftover dish. Although it looks fresh, bacteria have polluted your delicious food.
Leave 18 hours.
After 18 hours, the experimenter took out four plates marked "18 hours" from the refrigerator and put them in the microwave oven for heating and testing. The results showed that the nitrite content in stir-fried dishes increased significantly, by 44.3% compared with 6 hours, by 54% in braised crucian carp and by 47% in scrambled eggs with leeks, while the nitrite content in braised pork did not change much.
It can be seen from this experiment that the nitrite content of stir-fried dishes, braised pork and braised crucian carp exceeded the national standard after overnight dishes were put at noon the next day.
18 hour leftovers summary:
Except scrambled eggs with leeks, others are spared, because the antibacterial effects of leeks, onions and garlic are similar, which alleviates the deterioration of leftovers to some extent. Therefore, eating more onions and garlic can sterilize, and it seems that it is not groundless!
Let it stay for 24 hours
Almost 24 hours after the four dishes were cooked, the experimenter took out the last batch of four dishes marked "24 hours" from the refrigerator and put them in the microwave oven for heating and testing. The results showed that compared with 18 hours, the nitrite content of the four dishes continued to increase significantly, and all of them exceeded the limit standard of "Limits of Pollutants in Food".
The experimenter said that after 24 hours, microorganisms decomposed a large number of protein compounds, which promoted the transformation from nitrate to nitrite.
Learn more.
Early studies have found that ingestion of 3 grams of nitrite can lead to poisoning and death. Nitrite can oxidize low iron hemoglobin in blood to methemoglobin, lose oxygen transport function, lead to tissue hypoxia and even death. Long-term consumption will cause esophageal cancer, gastric cancer, liver cancer, colorectal cancer and other diseases. Adults ingesting 0.2 to 0.5 grams can cause poisoning, and 3 grams can cause death. Simply put, cook according to the quantity in the future, and don't leave leftovers.
Overnight vegetables are harmful to health.
Overnight food blacklist
1. Seafood products are only fresh.
The last overnight food to eat is seafood. Seafood from fish and shellfish can easily produce protein degradation products overnight, which will damage liver and kidney functions. Especially saprophytic seafood, such as shrimps and crabs, have all kinds of bacteria and putrefying substances in their stomachs. If you don't slaughter cooked food now, it's probably rotten food from the inside out!
2. Tremella can't be eaten overnight.
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.
3. Don't eat leafy vegetables overnight
Usually, the nitrate content of stem and leaf vegetables is the highest, while that of melon vegetables is 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. Be careful to drink overnight soup
It takes time to cook soup, so most people will cook a big pot and drink it slowly. However, if the soup is left in aluminum pot and stainless steel pot for a long time, it is prone to chemical reaction and precipitate harmful substances. It is recommended not to put salt and other condiments in the soup base. Cooked soup should be scooped out with a clean spoon, preferably in a glass or ceramic vessel and kept in the refrigerator.
7. Don't eat braised pork overnight.
To prevent food poisoning, don't eat inferior goods braised overnight in spring and summer. Food experts warn that even the food in the refrigerator is not absolutely "safe". Refrigerators are prone to mold and psychrophilic bacteria.