Spotlight on Science

Each month, an expert from the Marine Institute will shine a light on their area of work, sharing insights on our ocean knowledge. As the national agency responsible for supporting the sustainable development of our marine resources, the Marine Institute delivers scientific knowledge, expert advice and services to government, industry and a wide range of stakeholders.

Protecting the quality of Irish oysters

Bill Doré, Shellfish Microbiology Team Leader

Irish oysters are recognised globally for their quality and taste. Behind this reputation is a commitment to rigorous scientific testing which ensures they remain among the safest shellfish available on the international market.

One food safety risk associated with oysters is norovirus, also known as the ‘winter vomiting bug’. Oysters can accumulate the virus and occasionally, when eaten raw, outbreaks of norovirus illness can occur.

There are currently no legal limits prescribed in food safety regulation for norovirus in oysters in the EU. However, state agencies and producers in Ireland have been proactive in dealing with this food safety issue.

Since 2018, to support oyster growers in producing the safest oysters possible, the Marine Institute, with funding from Bord Iascaigh Mhara, has provided a norovirus testing service to Irish producers, who export oysters throughout the world.

Since the testing service began, the Marine Institute has analysed approximately 5,000 samples for norovirus. These data enable growers to proactively develop tailored risk management plans and implement mitigation strategies specific to their production areas.

The Marine Institute is the only laboratory on the island of Ireland that is accredited for the use of an internationally recognised standard method for the quantification of norovirus in oysters. This service not only supports oyster producers but also assists competent authorities and the Food Safety Authority of Ireland in investigating food safety incidents.

The impact of Marine Institute’s norovirus testing service is far-reaching. It enables Irish producers to confidently produce the safest possible oysters and supports their efforts to produce an internationally recognised high-quality product for export markets. In 2024, exports of Irish oysters were valued at ~€37 million, supporting businesses and employment opportunities in rural and coastal communities throughout the country.

An oyster related food illness incident can have a devastating impact on individual businesses and on the reputation of Irish oysters. The Marine Institute’s norovirus testing programme provides added food safety security, enhancing customer confidence in Irish oysters and giving Irish oyster producers a competitive edge in international markets.

The norovirus testing programme has also generated highly useful data. The Marine Institute now has the most comprehensive structured dataset for norovirus in Europe. This provides a unique insight into the risk factors leading to norovirus contamination in oysters and the effectiveness of post-harvest treatments.

This information assists decision-making by the competent authorities in Ireland and informs discussions at an EU level on the potential introduction of an acceptable limit for norovirus in oysters into food safety regulations.

In collaboration with BIM and Irish producers the Marine Institute’s norovirus testing programme helps to ensure that Ireland’s oyster industry remains resilient, competitive, and trusted.

The norovirus testing service has been funded by the European Maritime & Fisheries Fund (EMFF) and subsequently, the European Maritime Fisheries & Aquaculture Fund (EMFAF), administered by BIM.

This article first appeared in The Marine Times (October 2025). 

 

ENDS

For more information, please contact:
Kathleen Sweeney  e: kathleen.sweeney@marine.ie | m: +353 (0)87 094 5754
Sinéad Coyne  e: sinead.coyne@marine.ie | m: +353 (0)87 947 7090
Communications Office, Marine Institute  e: communications@marine.ie | t: +353 (0)91 387 200

Marine Institute
The Marine Institute is Ireland’s scientific agency responsible for supporting the sustainable development of the State’s maritime area and resources. The Institute conducts applied research and provides scientific knowledge, advice and services to government, industry and other stakeholders and users. www.marine.ie