Whether there are parasites or not, can not be generalized. In simple terms, there are fewer parasite problems in frozen fish, and if farmed fish are effectively managed, the parasite problem is more controllable.
Next, we will talk about the parasites that may be harmful to the human body that various fish may carry, the treatment countermeasures, the policies of various countries and the safety of farmed fish.
First, the parasites in marine fish.
First, it is important to make it clear that a distinction is made between parasites that are harmful to fish and parasites that are harmful to humans. There are many species of parasites that parasitize fish, but a large part of them are harmful only to fish, and these parasites are of particular concern to the fish farming industry, such as the fish lice that farm Atlantic salmon. But as consumers of fish, we are more concerned about the part of the parasite that will parasitize humans by eating fish.
One of the most infamous, worthy of everyone's vigilance is the xeno-cuspid worm. The fat salmon we often eat carries a lot of this parasite, and tuna and snapper also have certain risks. How harmful is this parasite?
In fact, the human body is not a good home for heterocephalus parasitism, they can not thrive in our body as adults, but it will still bring great harm to health. In general, there are two pathological symptoms of ingestion of xenohadist nematode: acute and allergic.
Within a few hours of eating, the xenohadist will try to drill holes in the wall of our intestines. But after all, the intestinal wall tissue is still strong and powerful for it, and it is difficult to penetrate completely, so the xenocephalus will get stuck on our intestinal wall, causing local tissue swelling and bleeding. It also triggers an immune response that envelops immune cells and causes the digestive tract to block, triggering acute and severe abdominal pain, nausea and vomiting.
Acute allergy symptoms such as urticaria and gastrointestinal pain will occur on the next use. There is currently no targeted drug for infection with isotidiasis, and taking albendazole (enteroxazole) to inhibit the parasite's absorption of glucose may work, but more often surgery is needed.
All 165 species of seafood off the coast of Japan have been detected in isotid nematode. Parasitic marine fish of heterocephalus include mackerel, horse mackerel, saury, salmon, cod, Far Eastern multi-line fish, octopus eye, squid, bonito, squid and so on.
The parasite of marine fish is much more than just an isocus nematode. For example, tapeworms that look like noodles, they parasitize in the small intestine after coming to the human body, and the manifestations of humans are abdominal pain and dysentery.
The large compound tapeworm likes migratory fish such as sardines, saury, mackerel, etc., and the parasites that have a special love for migratory salmon and trout are the Sea of Japan crackhead tapeworm, which are especially fond of cherry trout, birch trout and so on.
If you look at it purely from the perspective of appearance, it is still the recently discovered Kudao worm with high appearance. It is a class of myxospores that prefer to parasitize the flesh of turbots and also prefers young bluefin tuna. Human manifestations are abdominal pain, vomiting, and intestinal obstruction.
How to reduce the risk of parasites.
Most people dip mustard sauce in Japanese food, which is known as preventing parasites. However, in experimental cases, soaking for 45-55 minutes with a certain concentration of mustard may kill the parasite. But in reality, we can dip it at most, how can it be soaked for so long! And the so-called certain concentration, in the experiment can be carried out with 1-3g / ml, the real situation, we can not use such a high concentration of mustard.
In addition, vinegar and soy sauce or something do not want to think, parasites in the inside are alive by the day, but the high concentration of liquor in half an hour will kill the parasites, but who will put fresh sashimi in the wine for half an hour and then eat it? So those of us who eat sashimi dipped in mustard + soy sauce should not fantasize that spices can help us kill insects, and the prevention of parasites still needs to be carried out from the choice of ingredients.
1. Choose farmed deep-sea fish, don't hear the word wild and feel particularly tall. The containment of parasites from the source is deep-sea aquaculture, of which 75% of the fish we import from Norway, Scotland, Chile and other places are deep-sea aquaculture.
The whole process begins with artificial insemination of broodstock, to freshwater culture of fry, and then to marine aquaculture, to the fishing packaging of adult fish, all of which are strictly and accurately scientifically controlled. The control of feed and environment by farmed fish, the vaccination of fry, the strict disinfection of farmed fishing personnel, and the quarantine of import and export customs make these farmed fish have a high level of safety.
Wild fish are more dangerous in comparison, comparing 237 cultured salmon and 50 wild salmon in an experiment by the U.S. Food and Drug Administration (FDA) of heterocephalus iii larvae. Among them, none of the farmed salmon have been detected, but all 50 wild salmon have parasites, with an average of about 14 heterocephalus iii-stage larvae in each fish.
Although this experiment does not show that farmed fish are absolutely safe, it can fully indicate the danger of wild fish!
2. Rapid freezing is one of the most effective ways to eliminate parasites. Fish are handled in a second defense against the parasite after the selection of farmed fish. Of course, heating is the best way to kill parasites, but who makes us like to try raw and cold sashimi today ~ in the United States and Europe and the United States, in order not to damage the taste of meat and improve effective defenses, the common way is rapid freezing (IQF).
The FDA's recommendation is to freeze below -20 °C for seven days and below -35 °C for 15 hours, while the European Union stipulates that it is necessary to keep below −20 °C for 24 hours to kill parasites, in short, freezing is a very effective means of killing parasitic larvae and eggs. But we often like the big keywords of "chilled" and "air freight", and when we hear frozen, we think that the meat quality is not delicious.
In fact, the chilled fish after a series of processes such as processing, transportation, customs and so on will take 5-7 days, yesterday was still swimming in the Atlantic Ocean, today into our mouths of the situation is purely imaginary. The so-called chilled, meat quality is not much better. On the contrary, the ultra-low temperature freezing technology (below -55 ° C) can better ensure the taste and color of the fish.
3. It is best to understand the source of the fish eaten, especially those who like to buy and eat on the Internet, be sure to carefully ask the store whether there is a "Quarantine Certificate for Inbound Goods", and carefully read the above information. If you go to the store to eat sashimi, it is best to find a store with a large reputation for customers, and go to the supermarket to ask which ones can be eaten raw.
In short, sashimi is still a certain risk-taking thing, and you must always be cautious when buying and eating. Therefore, it is still recommended that whether it is marine fish or freshwater fish, it is the correct and safe way to eat fish by cooking with fire.