Mussels warning after Coromandel food poisoning outbreak

An outbreak of food poisoning has sparked a warning against eating raw mussels. Photo / File

New Zealanders are being warned not to eat raw mussels after a food poisoning outbreak that has closed a mussel-growing area in the Coromandel.

NZ Food Safety's director of food regulation Paul Dansted says an increase in food poisoning cases caused by the bug Vibrio parahaemolyticus in the past six weeks has been traced to "a single growing area in the Coromandel".

"This growing area has been closed by NZ Food Safety while further investigations continue," he said.

He warned New Zealanders not to eat raw mussels in the meantime.

"The mussels at the centre of the outbreak were all bought in their raw state, in the shell," he said.

"They are not the mussels that can be bought in plastic pottles. Those mussels are cooked and marinated and are not affected.

"Until we have more information, NZ Food Safety is reminding people to take care when handling, preparing, and consuming mussels.

"Cooking temperatures for mussels should be above 65C. This will ensure that any Vibrio parahaemolyticus that is present in mussels will be destroyed."

Vibrio parahaemolyticus is a marine microorganism that occurs naturally throughout the world.

"Not all Vibrio parahaemolyticus strains cause illness in humans and surveys to date of NZ shellfish have found very low levels and incidence of disease-causing strains," Dansted said.

"However, some strains do cause illness in humans. Symptoms are predominantly stomach cramps and watery diarrhoea and sometimes nausea, vomiting and fever.

"Generally people who are sick recover without hospital treatment, however, in severe cases hospitalisation is required.

"Additional testing is being done to confirm the type of Vibrio parahaemolyticus that has caused this illness. It is possible that the strain of Vibrio parahaemolyticus is unusually aggressive which may mean that even low numbers could cause illness.

"Additional testing of mussels and the waters that they are being grown in is also underway to help us understand why this has happened."

Mussel warning

• Don't eat raw or undercooked mussels or other shellfish. Cook them before eating.

• Always wash your hands with soap and water after handing raw shellfish.

• Avoid contaminating cooked shellfish with raw shellfish and its juices.

• If you are pregnant or have low immunity, avoid eating any raw shellfish.