In February this year, a 63-year-old man in Zhengzhou, Henan Province suffered severe diarrhea due to drinking a bowl of overnight beef soup, and was found to have caused a cerebral infarction.
Some people said that they had eaten leftovers from 4 days ago and were fine, but some people said that their leftovers were still covered with plastic wrap and were poisoned the next day.
Netizens argued with reason, no one is convinced, in fact, CCTV has already done experiments to prove whether these foods can still be eaten overnight meals and overnight tea.
1. Overnight meals
CCTV's "CCTV-17" channel once experimented with three dishes, namely braised beef, fried lotus root, and fried spinach.
The CCTV researchers experimented by measuring the taste, taste, and bacterial content of the three dishes after cooking them, and then placing the meals in the refrigerator for 12 hours to measure the same data again.
It was found that after 12 hours of refrigeration, the taste and taste of these three dishes did not change much, but the nitrite content of these three dishes did increase after refrigeration.
So what is nitrite and how does an increase in nitrite affect our body?
Then experts answered this question, nitrite is similar to edible salt, so it is widely used in industry, construction, and often used in meat products as a color agent in limited quantities.
However, once nitrite is used in excess, it will cause nitrite poisoning, and ingestion of 0.3~0.5g nitrite can cause poisoning, and 3g will lead to human death.
The World Health Organization has a clear regulation on the daily allowable intake of nitrite for the human body, which should not exceed 0.07mg per kilogram of adults per person per day.
If a person has 50 kilograms, then his daily intake is up to 50×0.07=3.5 (mg).
So after 12 hours of sitting, did the nitrite content of these three dishes exceed the standard?
As a result, the nitrite content of these three dishes was 9.36mg/kg, 5.92mg/kg, and 3.84mg/kg respectively after 12 hours of refrigeration.
Take the braised beef with the highest nitrite content as an example, if you want to achieve poisoning, you need to eat at least 32 kilograms of beef per day, that is, 64 catties of beef, which is simply impossible for normal people.
Therefore, it is a complete rumor that the overnight meal cannot be eaten, but the overnight tea is known as the "poisonous snake", so the overnight meal can be eaten, does it also mean that the overnight tea can also be drunk?
2. Overnight tea
Let's take a look at the experiments done by CCTV again.
CCTV did an experiment on overnight tea in the health program "Is It Real", and CCTV also invited senior tea taster Lou Guozhu to taste it.
CCTV experimented with Longjing, Pu'er and chrysanthemum, which are common in the market, first they brewed three cups of tea at 9 p.m., brewed three cups of tea again at 9 a.m. the next morning, and brewed three cups of tea again the next night.
In this way, a total of 9 cups of tea, separated by 12 and 24 hours, were respectively tasted by Lou Guozhu, who concluded that whether they were placed for 12 hours or 24 hours, their quality did not change.
On the contrary, it is Pu'er, and after being placed, its taste is more mellow and delicious.
Although the content of nitrite, which everyone is most concerned about, has increased, it is also within the range of safe drinking standards and will not cause harm to the human body.
And when netizens are happy about this result, overnight tea can be drunk, doesn't that mean that overnight water can also be drunk?
Just when netizens were happy about this, Lou Guozhu's words made people worry again.
Lou Guozhu told netizens that the nitrite content produced by boiled water after being placed overnight is definitely higher than that produced by tea overnight.
Because tea contains tea polyphenols, which are natural antioxidants, they can prevent the production of nitrite.
For a while, people were again in doubt, so can they drink the water overnight? This time, the staff of the Wuxi City Center for Disease Control and Prevention in Jiangsu Province started the experiment non-stop.
3. Overnight water
Wuxi CDC staff tested tap water, bottled water and bottled purified water.
They found that the nitrite content increased after 48 hours of cold or heated water, but it can be said that there was almost no change.
However, if the water is boiled many times and placed again, the nitrite content will increase significantly, although it is lower than the nitrite consumption standard, it is still not recommended to quote.
4. Recommendations
Although overnight meals, tea leaves, and water can be consumed, there are several ways to store them in order to avoid bacterial growth.
First of all, the refrigerator must be cleaned regularly, because the low temperature of the refrigerator inhibits the growth and reproduction of bacteria, so many people like to store food in the refrigerator.
However, a common problem that many people will make is that the food will be forgotten after being placed in the refrigerator, resulting in moldy and spoiled food in the refrigerator, bacterial proliferation, and affecting other fresh food.
Generally, the refrigerator should be cleaned every 3-6 months.
In addition, it must be divided before eating, many people live alone, for convenience, make two meals at a time, and then eat at night if you want to save trouble in this way, you must put out the extra meals in advance.
After eating, pack and pack, and the rest will inevitably get saliva and breed bacteria.
5. Conclusion
Everyone's safety and health are at stake, and we can't be too cautious.