Uncle Zhang, 72 years old this year, suddenly shivered and chilled after a lunch, and soon began to vomit and diarrhea, and his family rushed him to the hospital.
After examination, it was found that Uncle Zhang was severely poisoned by food poisoning and had developed multiple organ failures such as liver and kidneys. Although he has been out of the most dangerous stage after surgery, Uncle Zhang still needs to be admitted to the ICU (intensive care unit) for observation due to his weak body.
And the poisoning accident here turned out to be a plate of toon scrambled eggs. It turned out that it was the season when toons were on the market, and Uncle Zhang bought a lot of toons at once, all of which were used for scrambled eggs with white porridge.
Doctors said that toon is rich in nutrients, but at the same time, it also enriches nitrate in the soil and converts it into nitrite, which can bind to human hemoglobin, causing methemoglobinosis, which is life-threatening.
1. Toon contains nitrite, which is not only poisoning but also carcinogenic if eaten?
Every year in March of the lunar calendar is a good time for toon to go on the market, in a group of spring vegetables, toon with its unique fragrance makes the diners who love it can't stop, however, toon is often controversial because of nitrite content, and there are even rumors that the nitrite in the toon is excessive, and it will be poisoned and carcinogenic if eaten.
In addition to being rich in protein, fat, and carbohydrates, toon also contains potassium, calcium, magnesium, vitamin B group, phosphorus, carotene, iron, vitamin C and other nutrients.
Although toon is highly nutritious, it does contain a certain amount of nitrite substance. Why does toon contain nitrite?
This is mainly related to the environment in which they live. Plants need a certain amount of nitrogen fertilizer to grow. Nitrogen can be used in biochemical reactions to eventually synthesize amino acids, and nitrates are produced in the process. These nitrates can be reduced to nitrite with reductases in plants, which is why toons contain a certain amount of nitrite.
According to toxicological analysis, nitrite has a certain acute toxicity, and 57 mg/kg can be lethal to rodents.
But to talk about toxicity aside from dosage is to play hooligan. A 2006 investigation by Nanjing Forestry University found that none of the toon bud samples collected in six provinces on the mainland exceeded the national limit of 4 mg/kg.
In fact, according to the maximum intake set by the World Health Organization and the Food and Agriculture Organization of the United Nations, an adult with a body weight of 60 kg can consume 7.8 mg of nitrite, which is equivalent to eating about 2 kg of toon, and it is obviously unreasonable to eat 4 kg of toon at one time.
Comparatively speaking, the nitrate in toon deserves more attention. Nanjing Forestry University has found that the nitrate content in toon buds ranges from 500 mg/kg to 3000 mg/kg. This means that as long as you consume about 100 grams of toon, it is likely that you have already reached the upper limit of nitrate intake. (Adults weighing 60 kg, nitrate intake less than 216 mg).
Ruan Quang Feng, director of the Science and Technology Department of the Food and Nutrition Information Exchange Center, reminded that before eating toon, blanching it with hot water can remove a large amount of nitrite (data shows that 83.86% of nitrite can be removed as long as it is scalded for 45 seconds), so it is best to blanch the toon before eating it. In addition, when picking toons, try to choose young shoots, and fresh toons contain relatively few harmful substances.
2. 5 types of vegetables must be blanched before eating, otherwise it may be harmful to health
Most of the vegetables in life can be fried directly after washing, but in fact, some vegetables may carry natural "harmful molecules", before eating, it is best to blanch first, otherwise it may have a negative effect.
1. Vegetables containing a lot of oxalic acid: spinach/amaranth/celery
There may also be oxalic acid in green leafy vegetables, which is easy to combine with the body's calcium, iron and other mineral elements after eating, affecting the absorption rate of minerals, and may also stimulate the stomach and intestines, causing human discomfort.
For vegetables with high oxalic acid content, it is recommended to blanch them in boiling water for 15-20 seconds before the leaves darken before removing them for the next step of cooking.
2. Contains colchicine: daylily
Fresh daylily contains colchicine, which itself is non-toxic, but after entering the human body, it can be oxidized to colchicine, which can cause symptoms such as nausea, vomiting, and abdominal pain after consumption.
Colchicine is water-soluble, so fresh daylily must be treated before consumption to remove colchicine. If you like daylily, you can remove the stamens, blanch them again, and then soak them in cold water for more than 1 hour before eating.
3. Vegetables containing plant lectins: beans/green beans
Plant lectins are commonly found in legumes and vegetables, and after being eaten by the human body, they will produce nausea, vomiting, diarrhea and other poisoning phenomena. However, plant lectins have a weakness - they are not heat tolerant. It can be destroyed by heating it thoroughly, so with legumes, you can heat it on high heat for 10 minutes to reduce toxins.
4. Vegetables that are difficult to clean: broccoli/cauliflower/kelp
Flower bulb vegetables, there will be a layer of wax on the surface, but the vegetables have many flower spikes and dense fruits, and they cannot be completely and effectively cleaned with water. For this kind of vegetables, you can blanch them with hot water, which can basically remove pesticide residues, insect eggs and other pollution of vegetables.
5. Vegetables that are easily contaminated by microorganisms: bean sprouts
The growth environment of bean sprouts is warm and humid, which is more suitable for the growth and reproduction of microorganisms, making bean sprouts susceptible to contamination by pathogenic bacteria such as listeria and salmonella. Fortunately, these germs and bacteria are afraid of heat, and they can be killed by blanching them with hot water to ensure food safety.
3. Blanching is not simply boiling, to see if you are doing it right?
Blanching is a common process when cooking, but there is also a need for how to blanch. If you do it wrong, your nutrition and taste will be greatly reduced.
1. Cold water should be used for meat and hot water for vegetables
Blanching meat should be done in a pot under cold water to skim off the blood foam, while boiling water will destroy the protein, so that the surface of the meat will be cooked first, and the blood and water inside cannot be discharged.
Vegetables need to be boiled with water, and cold blanching will lead to the destruction of the physical structure of vegetables and the loss of nutrients.
2. Different ingredients, blanching time is different
There are not many leafy vegetables that do not need to be blanched for too long, and they may not be able to be removed after blanching bamboo shoots and calluses for 1 minute, so they need to be boiled for a longer time. Blanching cauliflower for 1~2 minutes, boiling water chestnuts and lotus roots for more than 1 minute, blanching for fresh daylily for 3~5 minutes, and blanching for beans and green beans for more than 10 minutes.
3. Add a few drops of oil and salt, and the vegetables will be greener
If you are worried that the color of the leaves will turn yellow after blanching, you can add a few drops of cooking oil to the water, which will prevent oxidase from destroying chlorophyllin.
4. Do not reuse the water after blanching
Oxalic acid, pesticides and nitrites dissolved after blanching are all in the water, and if the water is reused, these harmful substances may be ingested, so it is not recommended to continue using these waters.
Some vegetables may have their own "toxins", and scientific methods must be used to eliminate toxins before eating, so as to ensure the nutrition of vegetable leaves while reducing the harm caused by toxic substances.
Resources:
[1] "March 8, Eat Tsubaki Sprouts, "Vegetables on the Tree" to Eat Safe and Nutritious Like This". PSM Yaodun Public Welfare . 2022-04-27
[2] "These 7 types of vegetables have their own "toxins", and they must be blanched before eating! Popular Science China. 2023-03-30
[3] "Blanching is not simply boiling, let's see if you do it right?", Popular Science China .2023-09-20
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