People in the health care industry say you can’t eat leftovers. They absolutely can’t eat them. But there is such a question, after all, is it considered leftovers? Should all overnight food be dumped directly into the trash can? The health of others is actually unhealthy because of rumors. Of course, expert opinions must be based on facts. The following article will help you check it out clearly.

Can you eat overnight vegetables?

I believe that the third aunt at home said that the nitrite content in this overnight vegetable can easily cause cancer. The sixth grandmother said that overnight vegetables can be eaten, and she ate them all. For many years, the Eighth Aunt said that she would not get sick if she was not clean, but she was very confused about who to listen to.

In order to find out what overnight food is and how harmful it is, researchers from a laboratory at Zhejiang University decided to conduct a thorough study. They invited chefs from hygienic restaurants to cook four classic home-cooked dishes: stir-fried vegetables, scrambled eggs with leeks, braised pork and braised crucian carp to seriously study the health issue of overnight dishes, which has been discussed endlessly in the circle of friends.

Next, let’s take a closer look at how long the dishes have been left out before they can be called inedible overnight dishes!

First, the four dishes are divided into four portions immediately after being cooked. They are placed in disposable lunch boxes, wrapped in plastic wrap, and then stored in the refrigerator at 4°C.

After leaving it for half an hour

Half an hour after leaving the pot, the test results of the three dishes: fried vegetables, scrambled eggs with leeks, and braised pork showed that the nitrite content did not exceed the level in our country. The maximum limit value of the "Contaminant Limit Standards in Food". However, the nitrite content in braised pork is higher than that of scrambled eggs with leeks and fried vegetables.

In this regard, the experimenter said that meat dishes generally add more seasonings than vegetables. The seasonings themselves contain nitrates. These nitrates are converted into nitrites by microorganisms, which leads to Braised pork contains higher nitrite content.

Summary of the half-hour leftovers:

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 healthily, you might as well cook the meat a little lighter, and be careful not to cook too much meat at once!

Leave it for 6 hours

After 6 hours, it will be almost the time between lunch and dinner. It is common for many elderly people or two-income families to cook dishes at noon on their days off and eat them in the evening.

The experimenter opened the refrigerator and took out the fried vegetables, scrambled eggs with leeks, braised pork and braised crucian carp that were labeled "6 hours", then put them in the microwave and heated them over medium-low heat for 1 minute. The dishes still look fresh out of the microwave.

The experimenters measured the nitrite content of these dishes and found that the nitrite content in the leftovers increased after 6 hours. Fried vegetables increased by 16%, and fried eggs with leeks increased by 16%. 6. Braised pork has increased by 70%. Among them, the nitrite content in braised pork has exceeded the limit standard of "3 mg/kg for meat" in the national "Contaminant Limit Standards in Food".

Summary of the six-hour leftovers:

The braised pork has turned into a gorgeous “leftover” dish. Although it still looks fresh, the bacteria have contaminated your delicious taste. Delicious food.

Leave it for 18 hours

After 18 hours, the experimenter took out four dishes with the "18 hours" label from the refrigerator, heated them in a microwave oven, and tested them. The test results found that the nitrite content in fried vegetables increased significantly, 443% over 6 hours, the braised crucian carp increased by 54%, the leek scrambled eggs increased by 47%, and the nitrite content in braised pork did not change much.

It can be seen from this experiment that the nitrite content of fried vegetables, braised pork, and braised crucian carp exceeded the national standard when the overnight dishes were placed at noon the next day.

Summary of 18-hour leftovers:

Except for fried eggs with leeks, no one was spared. This is because leeks, like onions and garlic, have antibacterial effects, which alleviates the problem of leftovers to a certain extent. The situation of vegetables spoiling.

Therefore, eating more onions and garlic can kill bacteria, and it seems that it is not groundless!

Leave it for 24 hours

After almost 24 hours had passed since the four dishes were cooked, the experimenter took out the last batch of 4 dishes labeled "24 hours" from the refrigerator. Each dish was heated in a microwave oven for testing. The test results found that compared with 18 hours, the nitrite content of the four dishes continued to increase significantly, and all exceeded the limit standards of the "Contaminant Limits in Food".

Experimenters said that after 24 hours, microorganisms decomposed a large number of protein compounds, prompting the conversion of nitrate into nitrite.

Learn more

Earlier studies have found that ingesting 3 grams of nitrite can cause poisoning and death. Nitrite can oxidize low-iron hemoglobin in the blood. It forms methemoglobin and loses its oxygen-carrying function, causing tissue hypoxia and even death. Long-term consumption can cause esophageal cancer, gastric cancer, liver cancer, colorectal cancer and other diseases. Ingestion of 0.2 to 0.5 grams in adults can cause poisoning, and 3 grams can cause poisoning. It can be fatal. To put it simply, from now on, cook according to the quantity and don’t leave any leftovers.

Overnight food is harmful to health

Overnight food blacklist

1. Eat only fresh seafood

The worst food to eat overnight None other than seafood products. Fish and shellfish are prone to produce protein degradation products after being left overnight, which can damage liver and kidney functions. Especially for shrimps, crabs and other carrile seafood products, there are various bacteria and putrefactive substances in their intestines and stomachs. If they are not killed and cooked immediately, they are probably food that has been putrefied from the inside out!

2. Tremella fucii cannot be eaten overnight

Because both the tremella cultivated indoors and the tremella cultivated outdoors in basswood contain more nitrates. Over time, nitrate will be reduced to nitrite under the decomposition of bacteria.

3. Do not eat leafy vegetables that have been left overnight

Generally, stem and leaf vegetables have the highest nitrate content, melons and vegetables have slightly lower levels, and roots and cauliflowers are in the middle.

Therefore, if you buy different types of vegetables at the same time, you should eat stems and leaves first, such as Chinese cabbage, spinach, etc. If you plan to cook more dishes to eat hot the next day, you should try to cook less stem and leaf vegetables and choose melon vegetables.

6. Be careful when drinking overnight soup

Boiling soup takes time, so people usually boil a large pot and drink it slowly, but the leftover soup is left in aluminum or stainless steel pots for a long time. , prone to chemical reactions and the precipitation of harmful substances. It is recommended not to add salt or other condiments to the soup base. Use a clean spoon to scoop out the soup you want to drink that day. If you can't finish it, it is best to put it in a glass or ceramic vessel and store it in the refrigerator.

7. Do not eat braised food overnight

To prevent food poisoning, do not eat braised food overnight in spring and summer. Food experts remind that even food placed in the refrigerator is not absolutely "safe". Mold and psychrotrophic bacteria can easily grow in the refrigerator.