Two people are sick in New Zealand with food poisoning after eating mussels.

New Zealand Food Safety warned consumers to thoroughly cook mussels before eating after the duo became ill in the Nelson-Tasman region.

Vibrio parahaemolyticus is bacteria in mussels that may cause food poisoning if they’re not properly cooked or if they are intentionally eaten raw. People with low immunity, those who are pregnant or elderly should avoid eating raw or undercooked shellfish as illness can be more severe.

Paul Dansted, director of food regulation at New Zealand Food Safety, said: “While the cause has not been established both people who became ill have reported eating mussels and as a precaution we are reminding consumers to cook mussels thoroughly before consumption.

“New Zealand Food Safety is currently working with the Marlborough and Nelson District Health Board, the Marlborough District Council and the Institute of Environmental Science and Research to ensure appropriate public health measures are taken.”

Three times in three years
In 2019, an outbreak of Vibrio parahaemolyticus infection involved 24 people, of which two were hospitalized. It was linked to mussels and was the first such incident since 2009.

In June this past year there were eight confirmed cases of Vibrio Parahaemolyticus associated with eating mussels harvested from two commercial areas in the Coromandel region.

Cooking temperatures for mussels should be above 65 degrees C (149 degrees F) for one minute. This will ensure any Vibrio parahaemolyticus that is present will be destroyed. People are also encouraged to wash their hands with soap and water after handling raw shellfish. One way to know mussels are fully cooked is their shells pop open when boiled or steamed, and the mussel inside is firm to the touch.

Symptoms of infection are predominantly stomach cramps and watery diarrhea and sometimes nausea, vomiting, and fever. They usually occur within 24 hours of eating a contaminated product and last from one to seven days.