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Bivalve shellfish species, such as oysters, mussels and clams, feed by filtering large volumes of water. If the water contains harmful microbiological, chemicals or natural toxins, shellfish will concentrate these contaminants in their gut.
As shellfish are often eaten raw, and without removing the gut, eating these contaminated shellfish can cause foodborne illness.
To protect consumers, the Food Authority restricts when and where shellfish can be commercially harvested. The legal requirements are set out in the NSW Food Regulation 2025, which the Food Authority administers.
How harvest areas are classified
Before shellfish can be commercially harvested, the Food Authority assess all potential pollution sources likely to impact the harvest area. Sample sites are the established and situated to assess pollution impacts from the sources identified.
The Food Authority allocates a unique name to the harvest area and:
- thoroughly assesses all actual and potential pollution sources that could reach the harvest area from the land catchment, boating activity, marine wildlife and marine currents. Possible sources of contamination include wild and domestic animals and birds, sewage pumping stations, on-site sewage management systems (septic tanks) and industrial waste
- examines environmental features that will affect pollution levels in the harvest area, for example, soil types, slope of the land in the catchment area, tidal conditions and weather patterns. The interaction between the pollution sources and the environment means each harvest area has a unique food safety risk profile that will determine the harvest areas classification and harvest area management plan
- samples water and shellfish under a wide range of environmental conditions to verify that during all tides, weather patterns and seasonal activities, the shellfish continue to meet strict food safety standards
- assesses the natural phytoplankton and biotoxins active in local marine waters to identify any human health risk.
All this information is analysed and put into a written report, the Comprehensive Sanitary Survey. This states whether or not the area is suitable for use as a commercial harvest area, and what classification to apply.
Classification types
There are 2 main types of classification for shellfish harvest areas.
Conditionally Approved
Conditionally Approved harvest areas have no or very limited pollution when climatic conditions are fine. Shellfish from these areas can be harvested and eaten raw without the need for any other food safety treatment.
However, under certain known and predictable environmental conditions, pollution levels increase and harvesting must stop. Examples of such conditions include heavy rainfall, high river flows or reduced seawater salinity levels. Shellfish harvest areas have a specific harvest area management plan designed by the Food Authority which clearly identifies the conditions under which the harvest area must close, and the conditions under which it can reopen for harvest.
Conditionally Restricted
Conditionally Restricted areas have some pollution, but at levels low enough to be removed from the shellfish. Shellfish harvested from these areas must be treated in a manner approved by the Food Authority to remove any food safety risks (for example, depuration for 36 hours, or relaying to an Approved harvest area for 14 days).
Steps following classification
Once a harvest area is classified, the Food Authority will work with industry to develop:
- a harvest area management plan specific to the area. This will clearly document when and how to safely harvest shellfish
- a communication system, which can quickly advise all stakeholders of the harvesting status of the area
- a routine sampling plan to monitor microbiological and chemical pollution, and natural marine phytoplankton and biotoxin activity.
The status of each harvest area is published on our Harvest area status page.
Review of classifications
To maintain the classification status the area must be:
- operated in accordance with the local area harvest management plan, Food Regulation 2025 and NSW shellfish industry manual (PDF, 647 KB)
- reviewed annually by the Food Authority to ensure sampling results and environmental conditions in the area have not significantly changed.