Food poisoning from sushi can be caused by parasites like anisakiasis or bacteria like Vibrio or Listeria. Symptoms may appear immediately or within a few days, depending on the cause of the infection.
The only way to completely avoid sushi food poisoning is to avoid sushi made with raw or undercooked seafood. If you do choose to eat sushi made from raw fish, you can reduce your risk by choosing a reputable sushi restaurant and asking about the restaurant's food handling practices.
anisakiasis
Anisakis simplex (herring worm) is a fish parasite commonly found in Pacific salmon, monkfish, herring, haddock, flounder, and flukes. Eating raw or undercooked these fish may cause anisakiasis and other nematodes or roundworms in humans.
Ingestion of the tiny worms can cause severe abdominal pain, nausea and vomiting within hours of eating. What's more, if the worms aren't coughed up or vomited out, they can burrow into the walls of your intestines. This may lead to a local immune response or inflammation in the intestine.
If this does happen, the worms will eventually die and be cleared by the immune system. However, in severe cases, your doctor may need to remove them to relieve pain. This can be done through surgery or an endoscopy, which is a flexible tube and camera that allows doctors to see and remove them.
Freezing fish at minus four degrees Celsius or flash freezing at minus thirty degrees Celsius can kill anisakiasis.
Vibrio
Vibrio parahaemolyticus is associated with eating raw or undercooked fish and shellfish (especially oysters).
The infection can cause symptoms such as diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills. This condition can become severe in people with weakened immune systems.
Another type of Vibrio, Vibrio vulnificus, has been found in oysters, clams and crabs. In healthy people, ingestion of this microorganism may cause nausea, vomiting, watery diarrhea, abdominal cramping, and fever.
For people with liver disease or weakened immune systems, the microorganisms can enter the bloodstream and cause life-threatening infections throughout the body.
Additionally, Vibrio can cause wound infections through open sores exposed to water containing the bacteria. For example, opening an oyster or a scrape while working on a boat. As with gastrointestinal illnesses, these types of wound infections are most severe in people with compromised immune systems.
Listeriosis
Listeriosis is an infection caused by Listeria monocytogenes. This bacteria is found in raw seafood, unpasteurized milk and dairy products, vegetables and other foods.
The greatest risk for listeriosis is among the following groups:
- Pregnant
- Newborns (bacteria can cross the placenta)
- Over 65 years old
- weak immune system
If you are not pregnant, listeriosis may cause mild symptoms such as stomach upset and diarrhea. It may also cause flu-like symptoms, such as:
- fever and chills
- Muscle pain
- Headache
If the infection spreads to the nervous system, it can cause meningitis, which is an inflammation of the membranes and fluid surrounding the brain and spinal cord. People with meningitis can experience serious symptoms such as neck stiffness and confusion.
Listeria can also cause meningoencephalitis - inflammation of brain tissue and the membranes surrounding the brain. Nervous system infections are most common in immunocompromised people and the elderly.
If you are pregnant, listeriosis may cause miscarriage, stillbirth, premature birth, or serious infection in the newborn.
salmonella
Salmonella infections are caused by Salmonella enterica. Salmonella infection can cause the following symptoms:
- diarrhea
- fever
- stomach cramps
Some people may also experience nausea, vomiting, and/or headache. Symptoms usually appear within one to three days after eating contaminated food and can last up to seven days.
Salmonella infections can become serious, especially in infants, people over 65, or people with weakened immune systems. If you develop salmonella symptoms along with a fever over 102 degrees, bloody stools, or symptoms of dehydration, seek medical attention immediately.
Bacillus cereus
Bacillus cereus is another foodborne illness associated with eating sushi. This has been linked to the consumption of contaminated rice and other foods such as fish, vegetables, meat and milk.
There are two types of Bacillus cereus infections: diarrheal and vomiting. Diarrheal infection occurs quickly (within 6 to 15 hours) and causes the following symptoms:
- watery diarrhea
- Moderate nausea
Most people with this type don't vomit or have a fever. Symptoms usually disappear within 24 hours.
The type of vomiting is associated with contaminated rice products. An example might be fried rice that has been left at room temperature for a long time. This type tends to happen more quickly, within about one to five hours. It can cause:
- nausea and vomiting
- stomach cramps
- diarrhea
Serious complications, including meningitis, may also occur.
Tips for eating sushi safely
If food handlers do not practice good hand hygiene, other infections can be spread. People handling food should always wash their hands properly and stay home from work if they are sick.
When eating sushi at a restaurant, you can reduce your risk by choosing vegetarian sushi or cooked fish sushi. If you do choose to eat sushi made with raw fish, only choose restaurants with a good reputation.
If you are in good health, your risk of serious illness from eating sushi is low. However, you should be aware that there is always some risk involved in eating raw or undercooked fish. High-risk groups, such as infants and young children, pregnant women, the elderly, people with liver disease and people with weakened immune systems, are at a much higher risk of serious illness and should avoid sushi made from raw or undercooked fish.
If you do get sick, most illnesses will clear up on their own within a few days. Make sure to stay well hydrated and get plenty of rest during the recovery process. If you develop serious symptoms after eating sushi, such as vomiting that lasts for more than a few days, symptoms of dehydration, or bloody stools, seek medical attention.
generalize
You may be exposed to infectious diseases by eating raw fish from sushi or sashimi. These may be caused by worms or bacteria.
Many infections can cause digestive symptoms, including diarrhea, nausea, and vomiting.
