Crayfish, also known as fighting shrimp, is a mollusk that lives in fresh water. I believe that the delicious and tender lobster meat is familiar to everyone, especially in summer, spicy crayfish can always be seen on the roadside. But common sense tells us that good things are often poisonous. So is crayfish poisonous? What effect will crayfish have on human body? Let's have a look.

First, the harm of crayfish

The growth environment of crayfish is generally underground. The dirtier the environment, the more tenacious the vitality. Therefore, it is better to buy crayfish and cook them at home, so as to at least ensure the hygienic quality. You'd better ask if it's farmed when you buy it.

Crayfish (scientific name Procambarus clarkii, also known as Macrobrachium nipponense) is commonly known because it is similar to lobster in the sea.

It is reported that crayfish eat a variety of foods. Besides plant straws and aquatic plants, they also feed on dead fish or similar corpses. Because of their habit of eating carrion, they carry a lot of bacteria and toxic substances in their bodies. In order to make more money, some vendors organize manpower to catch crayfish growing in the wild environment in rivers and mud ponds, and transport them to the market for sale at low prices without quarantine. After many crayfish died, they became hotbeds for bacteria to breed.

Even artificial cultivation has some disadvantages. In order to cater to the growth habits of crayfish and shorten the growth cycle, some vendors deliberately feed unclean feed into the pond; What's more, if crayfish growing in polluted ponds and swamps are put on the table, it will pose a serious threat to people's health.

According to informed sources, the waters where crayfish live are full of plankton, both cultured and wild, which are hosts of parasites. In some countries, this species is also used to adsorb heavy metals and toxic substances in water. Eating this crayfish does have certain risks. If crayfish itself is infected with paragonimiasis cyst (the development period before the child worm in the life history of paragonimiasis), people may be infected with paragonimiasis if they do not pay attention to thorough cooking when eating, ranging from cough, chest pain and hemoptysis to epilepsy or hemiplegia. A few years ago, there was a case of "acute osteolysis" caused by crayfish poisoning in Beijing.

Second, how to eat crayfish?

Crayfish is the favorite of many friends in summer. Many people like to put a pot of spicy crayfish on the roadside stall to get addicted to their mouths, but the crayfish outside are generally unsanitary. If the hygiene is not up to standard, it will lead to diarrhea and even dehydration in severe cases.

Feed with clean water for 24 hours before cooking at home.

Experts say that when people cook crayfish at home, they must cook them thoroughly at high temperature. By observing whether the color of the cross section of shrimp is consistent, they can judge whether they are cooked or not. It is suggested that the shrimp must be fed with clear water for about 24 hours before cooking, so that the shrimp can spit out metabolites. In addition, it is necessary to clean the dirty things on its body with a brush, and at the same time, the gut line that hides a lot of sediment and bacteria must be removed, and then washed thoroughly with clear water for 2-3 times. Never eat shrimp heads that accumulate toxins and pathogens.

"The head of crayfish must not be eaten." Experts remind that crayfish's head absorbs and processes the most toxins, and it is also the most prone to accumulate pathogenic bacteria and parasites.

In addition, when eating shrimp, be temperate. Don't eat too much at a time, because shrimp is a high-protein food, and some people with allergies will have allergic symptoms to crayfish, such as red spots and pimples. It is best not to eat crayfish. Crayfish is an aquatic product with high purine content, which is not suitable for gout patients. The longer the shrimp dies, the more toxins are accumulated.

Shrimp is rich in histamine acid, which is the main ingredient that makes it delicious. But once the shrimp dies, histamine acid is decomposed into histamine substances harmful to human body by bacteria. Also, shrimp's stomach often contains pathogenic bacteria and toxic substances, which are easy to deteriorate after death. Especially with the extension of the death time of shrimp, more toxins are accumulated in shrimp, which will be poisoned if eaten.

In addition, there are many kinds of Paragonimus metacercariae and Vibrio parahaemolyticus in shrimp. If you eat undercooked shrimp, you will be easily infected with paragonimiasis, leading to gastrointestinal poisoning. Fresh shrimps should not be stored after being cooked, and must be reheated.

Vitamin c tablets should not be taken after eating shrimp.

Researchers at the University of Chicago in the United States found through experiments that shellfish such as shrimp contain high concentrations of "pentavalent arsenic compounds". The substance itself has no toxic effect on human body after eating, but after taking vitamin C tablets, the originally non-toxic arsenic compound can be turned into toxic arsenic trioxide, which is harmful to human life.

So be sure to pay attention to the way crayfish are eaten. Because most of us eat in barbecue stalls, if we don't pay attention, it may cause diarrhea, gastrointestinal discomfort and other diseases, which is also very bad for our health. So we must pay attention to reducing the chance of food poisoning.

Third, the difference between crayfish and crayfish

Lobster is expensive. It grows in the sea and has very high economic and nutritional value. Lobster contains less fat, but protein has more. Crayfish is a kind of freshwater shrimp, and the price of crayfish is economical.

Macrobrachium macrobrachium belongs to Lobster Family (Crustacea Decapoda), Eulobsters Family (Nephrobidae), Lobster Family (Macrolobidae), Cicadaceae Family (Scylla, Cicadaceae, Spanish Lobster, Oviposition Fish) and Polyphagidae Family (Polyphagidae). They are all marine creatures, living at the bottom of the sea and mostly moving at night. They feed on dead animals, but they also eat live fish, small mollusks and other benthic invertebrates, as well as seaweed. Some species, especially true lobsters and spiny lobsters, have important commercial value.

Origin: Central and South America and northeastern Mexico. Distribution status of China: It has spread to Shanghai, Jiangsu, Hongkong, Taiwan Province and other places, forming a large number of natural populations.

Crayfish (scientific name: Procambarus clarkii): also known as Procambarus clarkii, red crayfish and freshwater crayfish. Shaped like a shrimp with a hard shell The adult is about 5.6~ 1 1.9 cm long, dark red, with nearly black carapace and wedge-shaped stripes on the ventral back. Young shrimps are evenly gray, sometimes with black ripples. Long and narrow claws. The middle part of the carapace is not separated by a mesh gap, and there are obvious particles on the carapace. The frontal sword has a lateral thorn or a notch at the end of the frontal sword.

It is a kind of freshwater economic shrimp, which is widely welcomed by people because of its delicious meat. Because of its omnivorousness, fast growth and strong adaptability, it has formed an absolute competitive advantage in the local ecological environment. Its feeding range includes aquatic plants, algae, aquatic insects and animal carcasses. When food is scarce, they also kill each other. In recent years, crayfish has become an important economic species in China. In the process of commercial farming, it is necessary to prevent escape, especially to enter untouched original ecological water bodies. It has caused devastating damage to the ecological competitive advantage of local species.

Fourth, how to eat crayfish to be healthy?

First, go to the regular market to buy and choose crayfish with big head, white shell and strong vitality.

Second, it can be stocked in clear water before cooking, so that impurities such as sediment in the body can be spit out, shrimp cheeks and claws can be cut off, shrimp shells can be cleaned with a brush, and steamed thoroughly during cooking.

Third, when eating, we must pay attention to peeling off the shell and removing the internal organs.

Fourth, don't eat with persimmons, pomegranates, grapes and hawthorn to prevent tannic acid in these foods from forming insoluble substances with calcium in shrimp, causing gastrointestinal discomfort.

Fifth, crayfish should be eaten and cooked now, and try not to eat shrimp overnight.

Sixth, pay attention to observation when eating out. Don't eat crayfish with strong fishy smell, straight shrimp body, soft and inelastic meat, dark color and more sticky substances in the shell.

Seventh, don't eat too much crayfish. Allergy and gout patients should not eat.

How to judge whether crayfish is fresh?

When it comes to distinguishing the advantages and disadvantages of crayfish, it is actually very simple. Fresh crayfish are bright and full in color, firm in meat, and somewhat elastic and chewy. If it is a crayfish that has been placed for a period of time or has died, the meat is fresh and tender, and it looks empty and not full.