News

26.5.2009 - Report confirms Tauranga shellfish risky to eat

A year-long study of Tauranga Harbour and Waihi Estuary (Little Waihi) has confirmed that shellfish collected in these areas are often contaminated to levels that make them unsafe to eat.

The multi-agency study is the work of Toi Te Ora – Public Health, NZ Food Safety Authority, Environment Bay of Plenty, Tauranga City Council and Western Bay of Plenty District Council. 

Medical Officer of Health Dr Phil Shoemack says Tauranga Harbour is not unique in having contaminated shellfish.  “Shellfish harvested close to urban or significant pastoral farming areas are often contaminated. It is a common problem in New Zealand and also reflects the situation in many harbours around the world. The benefit of this study is we now have direct knowledge of the state of shellfish locally and can let people know of the risks,” he says.

The study showed a direct link between adverse pollution events such as heavy rainfall or sewage overflows and unsafe levels of viruses and bacteria in the gut tissue of shellfish collected at six points in the harbour and Waihi Estuary over a year.   

“By testing shellfish after a significant sewage overflow into the harbour, we found it takes three months for the contamination to reduce in shellfish found within 50m of the source.  For shellfish beyond 50m, it was one month before they were safe to eat,” says Dr Shoemack.

In addition to testing the viral and bacterial levels in the shellfish, NZFSA (NZ Food Safety Authority) scientists have tested cooking methods to determine when viruses are destroyed.  They found steaming or lightly cooking shellfish was not sufficient – boiling shellfish for at least three minutes was the only effective cooking method.

NZSFA  has long advised caution around consuming shellfish collected personally.  Shellfish are a high risk food because they can live in contaminated water and pick up and store any bacteria, viruses, biotoxins or pollution that are present, according to its ‘Food Safety for seafood gatherers guide’. 

The agencies involved in the study are working together to keep people informed of the risks of consuming shellfish collected from local harbours. 

“We will continue to work with the local councils to ensure signage is erected so people are aware of high risk areas and high risk times for collection of shellfish,” says Dr Shoemack.  “Information will be posted on the websites of all the agencies involved and we advise all shellfish gatherers to familiarise themselves with the NZFSA guidelines.  Booklets are available at the council offices and on the NZFSA website, at
http://www.nzfsa.govt.nz/consumers/hunting-collecting-fishing/seafood-gatherers/index.htm?print

Ends

For more information please contact:

Carol Wollaston    
Toi Te Ora Public Health – BOPDHB 
Tel: 07 579 8411                                

Amanda Weatherley
Environment BOP
Tel: 0800 ENV BOP

Marcel Currin    
Tauranga City Council   
Tel: 07 577 7026 or 027 4799 493   

Ruth Woodward
Western BOP District Council
Tel:  07 571 8008

NZFSA
Gary Bowering
Tel: 04 894 2500

< Back