PROTECTING THE QUALITY OF IRISH OYSTERS

Protecting the quality of Irish oysters

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.

Bill Doré, Shellfish Microbiology Team Leader

Irish oysters are internationally recognised for their exceptional quality and taste. Central to this reputation is a strong commitment to food safety, supported by rigorous scientific testing that ensures Irish oysters remain among the safest shellfish available globally.

One key food safety concern for oysters is norovirus, often referred to as the “winter vomiting bug.” As filter feeders, oysters can accumulate norovirus from their surrounding waters. When consumed raw, this can occasionally lead to illness outbreaks.

While no legal limits for norovirus in oysters currently exist in EU food safety regulations, Ireland has taken proactive steps to address the issue. Since 2018, the Marine Institute, with funding from Bord Iascaigh Mhara (BIM), has provided a dedicated norovirus testing service to support Irish oyster producers, who export their product worldwide.

To date, the Marine Institute has tested approximately 5,000 oyster samples for norovirus. This service enables growers to identify and manage risks specific to their harvesting areas, allowing them to implement targeted mitigation strategies and maintain high safety standards.

The Marine Institute operates the only accredited laboratory on the island of Ireland for the internationally recognised standard method of quantifying norovirus in oysters. This critical infrastructure not only supports the industry but also assists the Food Safety Authority of Ireland and other competent authorities in food safety investigations.

The impact of this testing service is significant. It helps Irish producers maintain the highest safety standards, reinforces consumer confidence, and enhances Ireland’s global reputation for premium shellfish. In 2024 alone, Irish oyster exports were valued at approximately €37 million, supporting jobs and businesses in rural and coastal communities across the country.

A single foodborne illness incident can severely damage both individual businesses and the broader reputation of Irish oysters. The Marine Institute’s testing programme provides a vital layer of protection, giving producers a competitive edge in international markets.

Beyond supporting day-to-day safety, the programme has also generated Europe’s most comprehensive dataset on norovirus in oysters. This unique resource offers insights into contamination risk factors and the effectiveness of post-harvest treatments. These findings not only guide Irish food safety decisions but also contribute to ongoing EU-level discussions around introducing regulatory limits for norovirus in oysters.

In partnership with BIM and Irish oyster producers, the Marine Institute continues to ensure the resilience, competitiveness, and global trust in Ireland’s oyster industry.

This testing programme has been funded by the European Maritime & Fisheries Fund (EMFF) and, more recently, the European Maritime Fisheries & Aquaculture Fund (EMFAF), both administered by BIM.

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

Main Image © Marine Institute