A recent spike in Vibrio parahaemolyticus cases is prompting a raw mussel warning from New Zealand Food Safety.

The organisation is advising people to stay safe from food poisoning by cooking mussels thoroughly before eating them.

New Zealand Food Safety director of food regulation, Dr Paul Dansted, says Vibrio parahaemolyticus are naturally occurring bacteria that are found in seawater and occur when warmer temperatures during summer are favourable for growth.

'We expect to see an increase in incidence of Vibrio parahaemolyticus in the warmer months.

'However, statistics from ESR show a recent spike in cases, with 22 since the beginning of the year.

'This compares with 14 for the first three months of 2020, and 4 for the same period in 2019.”

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

Dr Dansted says the consequences can be more serious for people with weakened immunity, the young, the elderly and frail, and pregnant women.

'As undercooked mussels can be a risk factor, it's important to take care with their preparation.

'To be safe to eat, thoroughly cook mussels at above 65 degrees C for one minute. This will ensure that any Vibrio parahaemolyticus present in the mussels will be destroyed.”

Dr Dansted says one good way to know when mussels are fully cooked is that their shells pop open when boiled or steamed, and the mussel inside is firm to the touch.

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

'It is raw mussels that we are advising against consuming. They are not the mussels that can be bought in plastic pottles. Those mussels are cooked and marinated and are not affected.”

For more information, visit these websites:

-Food and pregnancy https://www.mpi.govt.nz/food-safety-home/food-pregnancy/

-Food for people with low immunity https://www.mpi.govt.nz/food-safety-home/people-low-immunity/

-Food safety for fishers https://www.mpi.govt.nz/fishing-aquaculture/recreational-fishing/food-safety-for-fishers/