Some time ago, two "fat brothers and fat crabs" in Beijing were exposed by reporters to sell dead crabs as live crabs.
While strongly condemning the merchants, many netizens asked questions-
What's the harm of eating dead crabs?
How long does it take for crabs to die before they can eat?
How long can cooked crabs be kept?
......
While giving children delicious food, we should also pay attention to safety and give them crabs. You should understand this knowledge.
First, why not eat dead crabs?
High risk of poisoning
After the death of animals, the bacterial reproduction in digestive glands may lead to the spoilage of the whole food. As an omnivore, crabs are particularly risky.
There may be many bacteria in the food it eats. After death, bacteria multiply and corrode crab meat very quickly.
In this process, not only the taste and taste of crab meat are greatly reduced, but also some biogenic amines harmful to human body are produced, which cannot be removed even if heated at high temperature.
Some biogenic amines are very toxic. A few milligrams may cause poisoning, leading to vomiting, diarrhea, allergies and other symptoms, and may cause shock and organ failure in severe cases. Therefore, its content should be strictly limited.
Therefore, we really want to pursue the "freshness" of crabs. Even many online shops selling crabs will make promises of "guarantee freshness" and "compensation for dead crabs".
How long can I die before I can eat?
Some people think they spend a lot of money on crabs. If they die, they throw them away. Is there a time limit for eating them in a short time after death?
If we can know the time of death, it is acceptable in a short time.
Someone has done experiments. After standing for 3 hours at room temperature, the histamine content of hairy crabs increased from 3mg/ 100g to 6mg/ 100g.
After a few hours, it will increase to 7 or 8 mg, which may cause slight poisoning.
If completely refrigerated, it will almost reach this amount one day after death.
From the perspective of bacterial reproduction and histamine growth rate, dead crabs can be considered to give up eating if they are stored at room temperature for more than three hours or refrigerated for more than one day.
Again, only if you know when it died. If the hairy crabs at the food stall are dead, I suggest not buying them. When I woke up, I found that I was alive and dead last night. If you ask me, I'd better not eat either
Moreover, everyone has different sensitivity to these harmful substances, and only eating a little bit may cause adverse reactions. Dead hairy crabs are still not recommended to everyone.
How long can cooked crabs be kept?
People say I steamed the crabs alive, but I actually steamed a lot. Can cooked crabs last longer?
It's not just crabs. Usually, many leftovers can't be kept for a long time. Nutrients such as water and protein can still provide good breeding conditions for bacteria.
If it is stored at room temperature for less than 4 hours, or refrigerated for less than 1 day, it is ok to reheat it before eating.
But not longer than that.
As a reminder, crab shells are thick and difficult to heat through. You can steam them for a while or take them out and heat them separately.
Is it okay to freeze live crabs?
Besides buying fresh crabs, is there any other way to safely preserve crabs in advance?
You can consider putting the crab directly in the freezer when it is alive, and then taking the amount you want to eat every time you want to eat.
Related experiments show that even under the conditions of ordinary families, freezing for two or three weeks is basically no problem.
Freezing live crabs in the refrigerator at home is different from buying frozen crabs directly. Other self-frozen foods and quick-frozen products will have the same problem.
The temperature of frozen food in household refrigerator is gradually decreasing, and water will gradually form small ice crystals in microstructure, which may pierce the original cell structure. Specifically, meat quality may be affected.
The quick freezing process will not destroy the original cells and the quality will be higher.
Second, don't eat these four parts when eating crabs.
Jiang Hong, a nutritionist at Hangzhou First People's Hospital affiliated to Zhejiang University School of Medicine, once pointed out that when eating crabs, the stomach, intestines, heart and cheeks of crabs must be removed. These parts are organs for crab to filter and metabolize waste, which have no edible value and contain a lot of bacteria and parasites, which are easy to cause food poisoning.
Crab stomach, commonly known as "crab urine bag", is a triangular bone bag with sludge in the center of the front edge of its back shell. Crab intestine is a black line from crab stomach to crab navel; Crab heart is commonly known as "hexagonal plate"; Crab cheeks are commonly known as "crab eyebrows", that is, two rows of things as soft as eyebrows that grow in the abdomen of crabs.
Third, boil the water and steam the crabs for 20 minutes.
Boiling crabs with water will make the delicious nutrients in crabs spread into the water, thus destroying the delicious flavor and nutritional value of crabs. Steaming is a good way to cook crabs, because steaming is higher than boiling, which not only cooks quickly, but also kills microorganisms and parasites on crabs. Steamed crabs can also keep the integrity of crabs, make them ruddy and bright, and reduce the pollution of crab meat by gastrointestinal contents.
But it should be noted that crabs should be washed before steaming. Hold the two sides of the big cover at the root of the crab's two rows of legs with your hands (no matter how you move this place, the crab can't catch your hands), and then brush all the places that can be brushed with a toothbrush. When steaming crabs, you should pay attention to steaming the water for at least 20 minutes after boiling, and it is possible to kill germs when it is cooked thoroughly.
Fourth, eating crabs can be matched with warm stomach food.
Xu Huichao from the Nutrition Department of the Affiliated Hospital of Jining Medical College once pointed out that eating crabs should be accompanied by something that warms the stomach, such as Jiang Mo, vinegar, yellow wine, etc., which is related to the fact that Chinese medicine believes that crabs are cold.
In China, it has been thought that yellow wine and crabs are a perfect match since ancient times. Although crabs are delicious, they are cold, and eating too much can easily hurt the stomach. Yellow rice wine has the effect of promoting blood circulation and warming the stomach, so it has always been considered as the best choice for eating crabs to dispel cold.
Although crabs are delicious, don't eat too much.
The cholesterol content of crabs is very high, especially crab roe, so crabs should be eaten in moderation, not in excess, otherwise it will easily lead to high cholesterol. In addition, crabs are cool foods, and people with deficiency of spleen and stomach are not suitable for excessive consumption.
Sixth, picking crabs mainly depends on five aspects.
When choosing crabs, you should look at the following five aspects:
A look at the color, fresh crabs "green back and white belly, golden claws and yellow hair", the back shell is green and shiny, the abdomen is white and full, and it can spit bubbles constantly.
Second, depending on the individual, the choice of crabs should be big, old and healthy, so that the crab meat is more compact.
Third, look at the navel, the navel should protrude outward. Whether it is a male crab or a female crab, such crabs are generally full of fat.
Fourth, look at crab hair. Crabs with hairy feet and hard legs are the fattest.
Look at the action, fresh crabs have strong clamping force, complete crab legs, fast and powerful crawling, and agile and active movements. ④
Seven or eight people don't eat crabs.
Patients with hepatitis should not eat crabs.
Hepatitis patients are prone to dyspepsia, abdominal distension, vomiting and other symptoms due to gastric mucosal edema, abnormal bile secretion and decreased digestive function, while crab meat is rich in protein, which is difficult to digest and absorb.
Patients with cardiovascular diseases should avoid eating crabs.
Crabs contain high cholesterol, with 235 mg of cholesterol per100g of crab meat and 460 mg of cholesterol per100g of crab roe. Patients with coronary heart disease, arteriosclerosis, hypertension and hyperlipidemia eat foods with high cholesterol, which will lead to the increase of cholesterol and aggravate the development of cardiovascular diseases.
People who have a cold and fever should not eat crabs.
Cold diet should be light, high-protein crabs are not easy to digest and absorb, and it is easy to make a cold difficult to heal or aggravate the condition after eating.
Anyone with spleen and stomach deficiency and cold should not eat crabs or eat less.
Crabs are cold and easy to cause abdominal pain, diarrhea or indigestion after eating. Patients with chronic gastritis and gastric and duodenal ulcers had better not eat crabs, because eating them is easy to make the old diseases relapse or aggravate.
People with allergies should avoid eating crabs.
After such people eat crabs, specific crab proteins enter the body through the intestinal wall with increased permeability, resulting in allergic reactions and a large amount of histamine, causing gastrointestinal smooth muscle spasm and vascular edema, nausea, vomiting, abdominal pain and diarrhea; Some can also cause urticaria or asthma. In addition, people suffering from dermatitis, eczema, tinea and other skin diseases should also be careful to eat, because eating crabs will aggravate the condition.
People with biliary tract diseases should not eat crabs.
Such as cholecystitis and gallstones. The formation of cholecystitis and gallstones has a certain relationship with excessive cholesterol and metabolic disorder in the body. Eating crabs is easy to make the disease relapse or aggravate.
Pregnant women should eat less or not eat crabs.
Chinese medicine believes that crabs are cold and have the function of promoting blood circulation and removing blood stasis, so they are not good for pregnant women.
Eight, the first person to eat crabs
In China, crabs are not only a delicacy, but also a culture. For China people, eating crabs has a history of thousands of years.
Lu Xun's famous saying that "the first person to eat crabs is a warrior" has been passed down to this day, so who was the first person to eat crabs?
There is a legend in Suzhou: According to legend, in the Dayu era, river crabs were called "human-catching insects". When Dayu was harnessing the water, a supervisor named Plo dug a deep ditch and put hot water in the station to prevent the invasion of "human traps". As a result, the scalded "human flesh trap" has a unique fragrance, and Plough picked it up and tasted it. It was delicious. Since then, "arresting people" has become a delicious food on earth. Because the PLO suppressed this "human trap", it was named "crab".
In fact, China has a history of eating crabs for more than 6,000 years. In the Yangtze River Delta, archaeologists found a large number of crab shells in the waste eaten by ancestors, indicating that China people have a long history of eating crabs.
In the history of China, how many literati fell at the door of "heartless sons", and they all praised the delicacy of crabs from all angles. Xu Sidao, commander-in-chief of Wujiang River in Song Dynasty, wrote a poem entitled "You can't live up to your stomach without eating crabs", which became a famous sentence in crab culture and spread widely. Li Bai, a poet in the Tang Dynasty, once praised: "Crab claws are golden liquid, and bad mountains are Penglai. And you must drink wine on the platform next to the moon and get drunk. " However, among the poems about crabs in past dynasties, the most famous one is Pi Rixiu's poem about crabs, which says, "You were famous before you swam in the sea, but you have bones, and you were born of meat. Mo Dao is not afraid of thunder and lightning, and the sea dragon king is also crazy. " It took only a few figures, and the bullying and fearless temperament of crabs jumped to the page. "
Nine, the hands and feet are not enough? Tools gather together.
During the Ming and Qing Dynasties, it was a cultural enjoyment for literati to taste crabs. Everyone has a set of special tools when enjoying chrysanthemums and reciting poems and crabs. Suzhou, Shanghai and Hangzhou were once commonly known as "Eight Crabs". "Eight pieces of crab" include crab pier, crab hammer, crab axe, crab tag, crab scissors, crab pliers, crab knife and crab spoon, which have many functions such as cushion, knock, split, fork, shear, clamp, pick and hold.
First, put the crab on a small square table (crab pier), cut off two big claws and eight feet one by one with crab scissors, gently tap around the crab shell with a hammer, then split the back shell and navel with a crab axe, and then take a crab knife, crab tongs, crab sticks, crab hammers, crab spoons, or pick or clamp or fork or knock or hold them, and take out golden and shiny crab paste or creamy and tender crab meat. A tool is used in turn, and a function is played alternately, as if playing a cadence food song.
From the Ming Dynasty to the early years of the Republic of China, on this basis, 10 and 12 crabs appeared, and then there were as many as 64 sets of tools for eating crabs at most.
I would like to remind parents that although crab meat is beautiful, don't give your children too much, and don't give them dead crabs to save money.
Part of the materials in this paper are synthesized from nutritionist Gu Zhongyi, Health Times, Shandong TV Life Channel, Healthy Hangzhou, China Science Fair, etc.