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New Zealand Food Safety Advises Consumers To Cook Mussels Through

New Zealand Food Safety is reminding consumers to thoroughly cook mussels following an increase in cases of Vibrio parahaemolyticus around the country this summer.

Deputy Director-General New Zealand Food Safety Vince Arbuckle said, “Since mid-November 2021, there have been 31 confirmed cases with 10 people hospitalised with the illness from around the country, and evidence suggests a change in water temperature and conditions may make live mussels more susceptible to the bacteria.

“As mussel harvesting is a favourite summer pastime of many New Zealanders and are sold live and raw in many New Zealand supermarkets, we advise consumers to cook mussels thoroughly before consumption to avoid getting sick. We have been working with the major supermarket chains to ensure that point-of-sale signage to cook mussels is available for consumers.

"People with low immunity, pregnant, or elderly should always avoid eating raw or undercooked shellfish as the illness can be more severe,” said Mr Arbuckle.

New Zealand Food Safety advises consumers to follow simple food safety guidance to avoid contracting Vibrio parahaemolyticus by following some simple rules.

Keep hands and utensils clean

Always wash your hands and kitchen utensils after handling raw seafood, and before using other utensils or handling other foods. This will prevent the bacteria from spreading in your kitchen.

Cook mussels thoroughly

Cook mussels until steaming hot. Don’t eat them raw or lightly cooked as this won’t kill the Vibrio bacteria. One good way to know mussels are fully cooked is that their shells pop open when boiled or steamed, and the mussel inside is firm to the touch.

Chill mussels immediately

Refrigerate shellfish as soon as possible after harvesting from the beach or purchasing from the supermarket. You can use a chilly bin filled with ice or frozen ice packs to transport live shellfish in your car. Once you get home, you should store mussels in a bowl covered with a cold, wet towel on the bottom shelf in your refrigerator.

“New Zealand Food Safety is working together with public health units and the seafood industry to ensure appropriate public health measures are taken. However, consumers can minimise risks by cooking their shellfish thoroughly,” said Mr Arbuckle.

What to do if you get sick:

If you get sick after eating shellfish, phone Healthline for advice on 0800 61 11 16 or seek medical attention immediately. If possible, store and refrigerate any leftover shellfish for testing.

Vibrio parahaemolyticus symptoms may include watery or bloody diarrhoea, abdominal cramps, nausea, vomiting, fever, and/or headache.

For more food safety tips on harvesting and consuming shellfish, you can download advice in the pamphlet Food Safety for Seafood Gatherers on our website.


What is Vibrio parahaemolyticus?

V. parahaemolyticus is a bacterium that lives naturally in coastal marine environments and their presence is not related to faecal contamination or discharges from human activities. The bacteria can become concentrated inside shellfish as they filter water for food. It is found in coastal waters around the world and is not unique to New Zealand. Internationally, the numbers of V. parahaemolyticus cases are increasing.

How many people have been sick this summer?

Since mid-November 2021, there have been 31 confirmed reported cases with 10 people hospitalised from around the country.

How many Vibrio parahaemolyticus confirmed cases have there been in the past three years?

2019: 24 / 2020: 16 / 2021: 16

Does Vibrio parahaemolyticus have any impact on the seafood industry?

If there is an outbreak of disease in a specific commercial harvesting location, New Zealand Food Safety may impose a harvest and/or export restriction, which may impact those who sell live or raw mussels operating within the area. The operator will have to source their stock from mussel growing areas outside the harvest restricted location.

Is industry aware of this issue and what are they doing about it?

The aquaculture industry has been working closely with New Zealand Food Safety on this issue. They have been very proactive in working with industry members to minimise V. parahaemolyticus in the commercial food supply chain.

Is it safe to recreationally gather mussels from around the coastline in NZ to eat?

During summer months, when the seawater has reached its warmest temperature, the risk of illness from Vibrio parahaemolyticus is generally at its highest. New Zealand Food Safety recommends cooking mussels thoroughly to avoid the risk of getting ill. If you are concerned about other shellfish or you a person with low immunity, pregnant, or elderly you should always avoid eating raw or undercooked shellfish as the illness can be more severe.

We also advise recreational harvesters to mind biotoxin alerts in the region where they’re collecting shellfish as biotoxins cannot be removed by cooking. For more information, go to

Can I ever eat raw or lightly cooked mussels?

Vibrio parahaemolyticus is generally not considered a health hazard in shellfish when the seawater temperature where they are grown is 15°C or less. However, there may be other issues such as parasites and other bacteria and toxins that may make people sick so it’s important for those who are immunocompromised, pregnant, older and the very young to avoid eating raw seafood.

How many deaths in New Zealand have been caused by Vibrio parahaemolyticus?

There have been hospitalisations associated with Vibrio parahaemolyticus, but no deaths have been reported to date.

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