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Although our life is very good, it is the virtue of saving and some bad eating habits of China people that will cause obstacles to health. Many foods will produce toxins that are harmful to people's health after a night. So, what can't be eaten overnight?
Generally speaking, in order to be fresh, it is best not to eat overnight. There are many things that can't be eaten overnight, such as soybean milk. This paper only takes soybean milk as an example to explain, and other foods will be analyzed next time.
Soy milk:
? Soymilk is a common drink. Many people drink a cup of soybean milk for breakfast, but sometimes they are in a hurry and want to make it the night before and drink it the next morning. In fact, whether soy milk can be drunk overnight depends mainly on whether soy milk has deteriorated. If the microbial reproduction in soybean milk has not reached the level of harm, it can be drunk. If you can't guarantee the quality of overnight soybean milk, you can't drink it.
Soymilk has always enjoyed the reputation of "plant milk" in Europe and America. It is a drink made by soaking soybeans in water, grinding, filtering and boiling. Soybean milk is rich in plant protein, calcium, phosphorus, iron, zinc and other minerals. Protein in soybean milk belongs to high-quality protein, but the deficiency is that the methionine content is less. Among all kinds of bean products, soybean milk has the highest protein digestibility, reaching 95%. Protein in fresh soybean milk is the only plant complete protein similar to animal protein, and its amino acid ratio is close to the value needed by human body [1], which is beneficial for human body to absorb. In addition, soybean milk contains no cholesterol and the content of saturated fatty acids is much lower than that of milk. Soybean milk contains more dietary fiber, especially in the case of retaining part of bean dregs, drinking soybean milk is helpful to increase the intake of dietary fiber.
However, nutritious soybean milk is also a "culture medium" for microorganisms. Once the sterilization is not complete in the processing, it is easy to be polluted. Microorganisms will multiply rapidly in nutritious soybean milk drinks, and then rot and deteriorate, thus causing harm to human health [2]. Especially home-made soybean milk, because it has not been carefully disinfected and sealed, it is easy to cause bacterial invasion when exposed to the air. Even if it can be kept fresh in the refrigerator, it may deteriorate after the night.
Whether soybean milk can be drunk overnight, the main question is whether soybean milk has deteriorated. If the microorganisms in soybean milk grow and multiply to a certain extent, the nutrients of soybean milk itself are decomposed, or some substances harmful to human body are produced. In this case, it is not recommended for everyone to drink. You can also drink overnight soybean milk if it doesn't go bad overnight, your preservation and sealing conditions are good, and the growth and reproduction of microorganisms in soybean milk don't reach a harmful level. But the problem is that for ordinary families, the equipment and conditions needed for microbial detection are generally not up to standard, so we can't judge whether overnight soybean milk has gone bad, so whether to drink overnight soybean milk is a matter of different opinions.
Soymilk is rich in taste, delicate and smooth, and rich in bean flavor. It is a good choice for many people to have breakfast. Whether soy milk can be drunk overnight depends mainly on whether it has deteriorated. In addition, everyone should cook the soybean milk thoroughly, because the soybean milk without heating treatment contains anti-nutritional factors such as trypsin inhibitor and lectin, and the existence of these anti-nutritional factors will have adverse effects on soybean milk [3], and heating treatment will destroy the activity of anti-nutritional factors such as trypsin inhibitor.
refer to
[1] Lin Xudong, Pan Juzhong, Ling Jiangang. Health function and research progress of soybean milk [J]. Modern Agricultural Science and Technology, 2007(24): 146.
[2] Huang, Zhou, Bao Hairong, Preliminary study on microwave sterilization characteristics of soybean milk beverage [J]. Food Science, 2006 (12):152-156.
[3] Yang Xiaohui. Nutritional value of soybean milk-comparison between soybean milk powder and freshly ground soybean milk [J]. Soybean Science and Technology, 20 14(02):37-39.
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As a doctor, I am glad to answer this question. China is a thrifty country. Many people will store the leftovers and heat them up the next day. We must first understand a concept. What is an overnight dish? Is it an overnight dish? We think that more than 8 to 12 hours is an overnight dish.
The main harm of overnight dishes comes from the proliferation of bacteria, especially meat food, which is rich in protein, which is especially beneficial to the growth of bacteria, and the growth rate of bacteria is particularly fast, and the value added is doubled in a few hours. It can be said that any food, as long as it is left for a period of time, will certainly have bacteria breeding. In order to avoid bacterial reproduction, food must be stored in a low temperature environment and covered with plastic wrap. When you take it out again, you must heat it thoroughly to kill bacteria as much as possible.
So, which foods should never be eaten overnight? In fact, this question is absolutely necessary, and we can't give a definite answer. We can only judge by experience which foods are prone to produce harmful substances after overnight.
One is seafood such as fish and crayfish.
Protein of seafood is very rich, especially suitable for bacterial reproduction. In addition, crayfish add a lot of seasonings during cooking, which may also release harmful substances.
Second, soup, especially broth.
There are many nutrients such as amino acids in the soup. When we raise bacteria, we have a special broth culture medium, which means that broth is suitable for bacteria growth, and we should try not to spend the night in the soup.
Third, 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.
Generally speaking, try to eat fresh food, do not cook too much at a time, and do not advocate extravagance and waste.
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Regarding overnight meals, the problem of overnight meals has attracted a lot of attention, and most people are worried that overnight meals will produce toxic or carcinogenic substances. For example, in February, 20 12, an article by Weibo, "Eating overnight meals is 3.6 times the risk of stomach cancer", was actually exaggerated, exaggerating the harm of overnight meals, which is also to be refuted! Because not all overnight dishes can't be eaten, it can't be generalized, but also depends on how to store them.
So, what foods are not recommended for eating overnight?
1. Vegetables over 24 hours, especially cold dishes.
Vegetables contain high nitrite, which may be gradually transformed into toxic nitrite due to the activities of bacteria during storage. But if it is only stored in the refrigerator for one night, the rise of nitrite is far from causing food safety accidents. But if it exceeds 24 hours, especially cold salad, it will easily lead to excessive intake of nitrite.
2. Fish, shrimp and bean products that have been put in the refrigerator for more than 3 hours.
Fish and bean products are mainly bacterial reproduction problems, most afraid of causing Botox reproduction. This kind of bacteria is very toxic, especially if it is kept in the refrigerator for more than 3 hours, it is best not to apply it again. Clostridium botulinum toxin can be destroyed by heating above 100 degrees for a few minutes, but it is very dangerous if the heating is not thorough.
It is worth reminding: Never heat dishes repeatedly. Repeated high-temperature heating will denature protein and produce harmful substances. If you know you can't finish the fish in the second meal, heat half of it and put the rest back in the refrigerator. Otherwise, I would rather throw it away.
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In fact, there is no food that can never be eaten overnight. The key is whether the cooked food is properly preserved. Of course, food must be made reasonably first. For example, if you cook it half-baked on the first day, don't eat it overnight.
(1) overnight tea and overnight water:
It is rumored that overnight tea and overnight water will produce a lot of nitrite, which is harmful to the body and even carcinogenic. Actually, it's not that exaggerated.
In general, overnight tea and overnight water can indeed contain a small amount of nitrite. If it is stored improperly (for example, it is not sealed), the content of nitrite will continue to rise.
For overnight water, it is found that the nitrite content does increase with the increase of overnight days, but it is still within a reasonable range and suitable for drinking.
As for carcinogenicity, it is even more unreasonable. Because nitrite is not a carcinogen, it is produced under certain conditions? Nitrosamine? It is a carcinogen.
Therefore, in general, the nitrite content in overnight tea and overnight water is safe, and we don't have to worry about their carcinogenic problems at all.
Of course, the taste of overnight tea is not as good as that of new tea, so it is better not to spend the night as much as possible.
(2) Watermelon overnight:
Watermelon stored for a long time is easy to breed bacteria, but as long as it is stored properly, it will not cause harm to the body even if it stays overnight.
So, what should we do with these endless watermelons?
It is recommended to seal it with clean plastic wrap and put it in the refrigerator for refrigeration. Plastic wrap can prevent cross-contamination between foods, and cold storage can reduce the propagation speed of bacteria and prevent watermelons from deteriorating too quickly. In this process, we should also pay special attention to whether the operator's hands, knives and chopping boards are clean.
Of course, the best way is not to buy too many watermelons and try to finish them on the same day.
(3) Overnight leftovers:
Many people worry that eating overnight leftovers will cause cancer, but they are actually talking about the problem that it contains nitrite.
Nitrite can be transformed from nitrate, which is commonly found in vegetables (such as spinach and cucumber), but the nitrate content of these vegetables is high or low, so the nitrite content produced is also different.
Vegetables left overnight will produce more nitrite if they are contaminated by microorganisms. Therefore, whether leftovers can be eaten overnight depends on whether these dishes are properly preserved. Specific preservation suggestions are as follows:
First of all, compared with meat, vegetables are not suitable for overnight, because vegetables themselves may contain more nitrate, so the nitrite produced will increase accordingly;
Secondly, if you can't finish eating some meat that day, you should pack it in time and put it in the refrigerator after cooking, instead of waiting to turn it over with chopsticks for countless times before storing it;
Thirdly, in the process of refrigeration, the leftovers must be sealed and preserved, for example, first put in a clean fresh-keeping box and then put in the refrigerator for refrigeration;
Finally, try to shorten the time of overnight dishes, and be sure to fully heat them before eating.
In addition to overnight tea, overnight water, overnight watermelon and overnight leftovers, I believe many people have also heard that overnight tremella, overnight seafood, overnight eggs, overnight soybean milk, overnight soup and so on cannot be eaten. In fact, the truth is the same. The key is whether these foods are properly preserved.
(Image from the Internet)
Author: Liu Pingping, nutritionist &; Popular science author.
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Can't you eat overnight dishes? This topic has been discussed for many years. Really can't eat? In fact, it may not be, mainly because of improper storage or handling, which leads to the risk of treatment after eating overnight dishes. Although you are advised to eat fresh ingredients instead of overnight meals, the risks of overnight meals are often exaggerated and exaggerated.
Overnight vegetables produce nitrite, so don't eat them? -It's fake!
From the production mechanism, no matter whether it is ripe or not, nitrite will be gradually produced as long as it leaves the land and is placed, especially green leafy vegetables. Therefore, I suggest that everyone must eat fresh vegetables and freshly cooked vegetables, and buy, cook and eat now. This is the healthiest way.
But is the amount of nitrite produced by vegetables overnight enough to trigger a poisoning reaction? Aside from the dose, talking about toxicity belongs to hooliganism. This is a rumor, cooked vegetables, left overnight, will it produce nitrite? Yes, there is a laboratory that tests nitrite in vegetables overnight. The results showed that the nitrite content of overnight dishes was indeed higher than that of cooked dishes, but its consumption was far below the national standard limit of nitrite in meat processing in China.
Therefore, pharmacist Li's point of view is that it is not recommended to eat overnight dishes, because it is not fresh and nitrite will increase, but compared with the processed meat products you bought, the nitrite content in them is negligible. Eating healthily is not as simple as throwing out leftovers. Eat less processed meat and eat less nitrite!
Crabs and crayfish overnight will produce toxins and must not be eaten. Is it true?/You don't say. /You don't say.
It also depends on the storage method. Don't worry too much about seafood preserved in cold storage.
Let's analyze how this toxin is produced. For some foods with high nutrition, bacteria will multiply during storage. The reproduction speed of bacteria is logarithmic, that is, 1 change 2, 2 change 4, 4 change 16, 16 change 256 ... This speed is very fast. For a bacterium, it is called. However, it will leave a toxin, usually called endotoxin. This toxin itself has no activity, so it will not be destroyed by high temperature. However, it does have certain toxicity to human body, often causing fever and leukocyte reaction, and even causing endotoxic shock and other problems in severe cases.
Therefore, if the temperature can be controlled to reduce the reproduction and development of bacteria, the stored food will generally be heated before use, and the danger is not great. It is suggested that if you are reluctant to throw away the leftovers of high-protein food, you can put them in the refrigerator storage room with zero freshness, take them out the next day, and heat them to 100℃ before eating. It's usually nothing serious.
If you want to say that overnight dishes can't be eaten, it is-spoiled overnight dishes can't be eaten! The reason why it goes bad is that improper storage leads to large-scale reproduction of bacteria. On the other hand, it is still the problem of bacterial toxin residue mentioned above. Therefore, for spoiled food, heating in time kills all the bacteria, and the toxins in it can't be removed, and the taste is bad. So, you must not eat any more.
Finally, I recommend you to eat fresh ingredients. You can eat overnight dishes, but try to eat as little as possible and store and process them in an appropriate way.