How to prevent anisakis parasites

Updated April 17, 2017

The common round worm anisakis simplex can end up in your food and cause you to contract the infection anisakiasis. According to the Centers for Disease Control and Prevention, the tiny anisakis, or sushi worm, makes its way into a number of different hosts before the larvae infects the intestines of fish. When people eat contaminated raw or undercooked seafood the infection anisakiasis can result. While the surest way to prevent anisakiasis is to give up raw or undercooked seafood and fish, taking precautions will allow you to savour your favourite seafood worry free.


Learn what species of fish tend to host the anisakis worm, such as wild caught pacific salmon, sole, flounder, halibut, herring, mackerel, small tunas, octopus, squid, snails, crayfish and crab, according to the "Journal of Food Science."

Recognise what the anisakis looks like: The sushi worm grows to 0.79 inches long and coils up on the fish skin or invades the intestines. You may find anisakis in the belly of the fish.

Cook seafood thoroughly to an internal temperature of at least 62.8 degrees C (63C), according to the Food and Drug Administration.

Freeze fish at a temperature of minus 4° F (minus 20° C) for at least one week. Flash freeze fish to a temperature of minus 31° F (minus 35 °C) and keep it at this temperature for 15 hours, advises the FDA.


When dining at a sushi bar, ask if the raw fish has been previously frozen to prevent the risk of anisakis infection.


Even if you have been successfully treated for anisakiasis in the past, you can develop another infection if you eat contaminated fish again. Salting fish kills only exterior parasites. Do not trust this method to eliminate anisakis that has already burrowed into the fish.

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About the Author

Stacie Dagres began writing professionally in 1994. Her writing experience is drawn from a background in government, business and nonprofit organizations. Dagres' work has appeared in numerous government publications and a regional radio network, while her public relations writing has been published in newspapers, magazines and online. She holds a Bachelor of Science in geography from the University of Idaho.