First and foremost, it should be understood that the contamination of fish with helminths, i.e., parasitic worms, is not considered a prerequisite for a ban of the sale of the product. If the fish is fresh, complied with all the rules of storage and processing, but it when testing revealed several (10) of worms, it may be sold in any supermarket. To protect the rights of the buyer sanitary service will only be in the case of a strong excess of admissible norms.
Choose those fish that are less susceptible to helminthiasis. For example, for sturgeon, the disease is less characteristic, and larvae that can be found, not dangerous to humans. Through the fish of the carp family (bream, sazan, vobla) can easily be infected with opisthorchiasis, and predatory species (pike, perch, Zander, burbot) will almost always be a carrier of the broad tapeworm.
Some parasites can be found in the external examination. So, pike, carp, tench, burbot can be parazheny lineatum (parasitic crustaceans). Body noticed the bumps, of which sticks out brown rod length to the centimeter. Suspicion should also cause brownish-black spots on a body, they are caused by posthodiplostomum. Sometimes you can find carp, carp or tench with a mass of small thin striped leeches, stuck to the head or front part of the body is piscicoles.
After purchase, open the abdomen of the fish and inspect the insides. Suspicion should cause small white worms, gray-white (pinworms), large red-yellow roundworm, little vlasoglavy length of 3-5 cm, with long and narrow front, wide ribbon-like parasites (lentity). This is the most dangerous to human individuals, and the most common fish in the river.
Discovered parasites can easily remove the viscera. But the infection often affects not only the gut, but the muscle tissue, i.e. meat. If at survey you have noticed in the meat of suspicious strings, ribbons and eggs — the fish should be discarded.
A few parasites in their intestines should not confuse practical mistress. This fish may well be edible and safe after a good heat treatment. Experts recommend stewing or boiling at 100 degrees, for 30-40 minutes. Remember — if you are found in fish worms, it does not mean that they are not there. It's possible you have not noticed, or it was just eggs.