These 4 overnight dishes are too dangerous. It is best to throw them away if you can't finish them.

It is said that "thrift is a traditional virtue of the Chinese nation", but when faced with leftovers at home, many people are in a dilemma: throw it away, it is a waste; heat it up and eat it the next day, but words like "excessive nitrite", "carcinogenic", and "poisoning" make people worry...

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Can we still eat leftover food? Which dishes should be thrown away without hesitation, and which can be saved for the next meal? How should we deal with leftover food scientifically? Today, let's answer them one by one~

Overnight food contains nitrite

Is it toxic and carcinogenic?

First of all, we need to make it clear that the so-called "overnight food" does not simply refer to the food left over from the day of the meal and left for the next day . Scientifically speaking, food that has been left for more than 8-10 hours is considered overnight food.

The longer the food is stored, the higher the nitrite content will be. Many people are always worried that eating food will cause nitrite poisoning or even cancer. Is this really the case?

1. Nitrite itself is not carcinogenic

In fact, nitrite itself is not carcinogenic. It is widely present in the natural environment, especially in food. For example, the average nitrite content in vegetables is about 4 mg/kg, meat is about 3 mg/kg, and eggs are about 5 mg/kg. After being picked and harvested, vegetables and fruits will continue to produce nitrite.

In addition, nitrite is also a legal food preservative . As long as it is within the national standards, there is no health risk. For example, nitrite may be added to the pickled foods such as ham and bacon that we often eat in our lives.

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2. Under certain conditions, nitrite is toxic

However, it is not entirely groundless that people always say that overnight food is toxic and carcinogenic :

On the one hand, if excessive intake of nitrites in a short period of time, it will cause acute poisoning , affecting the functioning of red blood cells and making the blood unable to transport oxygen. In mild cases, symptoms may include dizziness, weakness, chest tightness, shortness of breath, nausea and vomiting, abdominal pain and diarrhea, and blue lips and fingertips; in severe cases, it may lead to brain hypoxia and even death.

On the other hand, when nitrite enters the acidic environment of the stomach, it will react with the protein eaten to produce nitrosamines, which are truly carcinogenic . Long-term and large-scale consumption may cause cell mutations and even induce gastric cancer, esophageal cancer, liver cancer, colon cancer and other cancers.

3. Does the nitrite content in overnight dishes exceed the standard?

According to the Chinese Journal of Preventive Medicine, the minimum toxic dose of oral nitrite for adults is about 300mg-500mg, and ingestion of 1-3g can cause death.

What does this mean? Generally speaking, overnight food stored in the refrigerator for 24 hours (excluding pickled vegetables and processed meat) will not contain more than 10 mg/kg of nitrite.

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Therefore, the nitrite content in overnight food is still far from the toxic dose, and it is not so easy to cause acute poisoning . It is not a big problem to eat a little occasionally. There is no need to be afraid of overnight food.

These 4 overnight dishes are too dangerous to finish

Better pour it out!

So, can we eat leftover food without any worries? No!

This is because overnight food is likely to lose a lot of nutrients during storage and reheating, and it is easy to breed bacteria, which can easily cause gastrointestinal discomfort or even food poisoning after consumption. In particular, the following four types of overnight food are more harmful to the body and are best thrown away if you can't finish them:

1. Overnight green leafy vegetables

Eating green leafy vegetables regularly has many benefits . According to the "Dietary Guidelines for Chinese Residents", adults should eat 300-500 grams of vegetables every day. But there is an old saying: "It is better to have leftover meat than leftover vegetables."

After being stored for a long time and reheated, vegetables lose a lot of nutrients, their taste changes greatly, and they are more likely to spoil. Moreover, compared with meat, fruit and other foods, green leafy vegetables themselves have a relatively high nitrate content. If they are left for too long after being cooked, the nitrate will be reduced to nitrite under the decomposition of bacteria, which is not good for your health.

If not stored properly, the nitrite content may exceed the standard ! Zhejiang Ningbo Food Inspection Institute once conducted an experiment and found that after celery, lettuce, water spinach and other green leafy vegetables were fried and stored at room temperature of 25°C, the nitrite content reached an astonishing 100mg/kg after 24 hours.

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[Tips] : Although it is irresponsible to talk about toxicity without mentioning dosage, and eating a little occasionally may not be a big problem, it is still recommended not to eat green leafy vegetables overnight.

2. Overnight seafood

Seafood such as crabs, fish, and shrimps are high-protein foods. If you do not finish eating them on the same day and eat them overnight, protein degradation products may be produced, which can easily damage liver and kidney functions.

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In addition, seafood products such as shrimp and crabs may contain various bacteria and corrupt substances in their stomachs. If they are not cooked while they are fresh, they may become corrupt from the inside out !

3. Overnight Tremella Mushrooms

Many people will stew a pot of Tremella soup and put it in the refrigerator to eat several times. But this practice is actually very dangerous !

Whether it is indoor cultivated Tremella or wild Tremella and mushrooms, if they are left for a long time after being cooked, they are more likely to breed bacteria, and symptoms such as abdominal pain and diarrhea may occur after eating.

[Tips] : It is okay to seal the Tremella soup and refrigerate it for 1-2 days; but if it is more than 3 days, it is best not to drink it; and if the leftover Tremella in the bowl is not refrigerated, it is best not to eat it the next day.

4. Overnight soft-boiled eggs

Many people prefer to eat half-cooked "soft-boiled eggs" rather than fully cooked white-boiled eggs. However, these half-cooked eggs are not sterilized thoroughly and may contain a variety of pathogenic bacteria such as salmonella ; if left for a long time, it is easier for bacteria to grow , which will harm the intestines after consumption.

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[Tips] : If the eggs are cooked for the first time and stored at a low temperature and in a sealed environment, it is generally okay to eat them overnight.

Scientific storage of leftovers

Eat more safely

In fact, whether overnight food is safe and edible depends more on the storage conditions .

If good storage conditions can be ensured and secondary contamination by foreign bacteria can be reduced, some overnight dishes can still be served; but if stored improperly, some foods may only be left for a few hours and may deteriorate or produce harmful substances, which is very bad for health after eating.

Generally speaking, it is best to cook as much food as you can eat. If you cook too much and cannot finish it, you can follow the following 4 points to deal with the leftovers:

1. It is better to leave meat dishes than vegetables dishes.

When there are bound to be leftovers during a meal, vegetables should be eaten first, and any leftover meat or non-vegetarian dishes can be saved for the next meal. For details, please refer to the following storage time ranking:

Green leafy vegetables : storage time 0 days (salad vegetables should be eaten as soon as possible);

Staple food : storage time 1 to 2 days;

Meat dishes from livestock and poultry : The storage time shall not exceed 3 days.

2. Put in the refrigerator while hot

The longer leftovers are left at room temperature, the greater the risk of bacteria growing; moreover, some of these bacteria produce toxins that may not be killed by normal home cooking.

Therefore, when the dishes have cooled down to a temperature that is not too hot to touch, you can pack them in fresh-keeping containers and put them in the refrigerator. Don’t wait until they are completely cold before putting them in the refrigerator.

3. The location of leftovers in the refrigerator is also important

① The upper layer of the refrigerator area : leftovers and other cooked food can be placed;

②The middle of the refrigerated area : suitable for fruits and vegetables;

③The constant temperature refrigerated area at the bottom : can be used to store eggs, dairy products, soy products and meat to be eaten that day.

Keeping raw and cooked food separate can prevent parasites and bacteria carried in raw food from falling onto cooked food such as leftovers when eating, thereby reducing the risk of cross infection.

4. Heat thoroughly before eating

Leftovers must be thoroughly heated before eating, especially meat. Thorough heating means heating the entire dish to 100°C and keeping it boiling for more than 3 minutes.

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To avoid uneven heating, you can use tools such as chopsticks and forks to look inside the food to make sure it is heated thoroughly before taking it out of the pot.

Source: I am a great doctor official account

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