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Fish & Shellfish

FSS is required, by European legislation, to undertake an extensive programme of Official Control monitoring of LBMs and marine phytoplankton (algae) from LBM harvesting waters.

Safety and harvesting

Food Standards Scotland is the Competent Authority which is responsible for undertaking Official Controls to determine the safety of marine waters used for the harvesting of live bivalve molluscs (LBMs) in Scotland. LBMs include shellfish such as mussels, oysters, clams, scallops and cockles.

The results of this programme are used to determine whether an area should be open or closed for harvesting depending on the levels of microbiological and chemical contaminants including marine biotoxins. More details of the individual strands of this programme are outlined below.

Sanitary surveys

Sanitary Surveys are required under European legislation relating to official controls on live bivalve molluscs intended for human consumption (EC Regulation 854/2004). The surveys are intended to provide a thorough assessment of microbiological pollution sources, develop the most representative sampling plan and identify appropriate production area boundaries for all new shellfish production areas. The sources and types of microbiological contamination that might affect new and existing shellfish production areas are examined in detail.

More about sanitary surveys

The following information is reviewed and assessed:

  • location and extent of the shellfish production area
  • type of shellfishery (species, method of harvest, seasonality of harvest)
  • location, type and volume of sewage discharges
  • location of river inputs and other potentially contaminated water courses (from OS maps/nautical charts)
  • location of harbours and marinas (from OS maps/nautical charts)
  • hydrographic and hydrometric data
  • existing microbiological data from water quality or shellfish monitoring undertaken in the same area or adjacent areas

Available information is supplemented by a practical shoreline survey.

CEFAS (Centre for Environment, Fisheries & Aquaculture Science) have been undertaking sanitary surveys on our behalf since 2007 and have completed over 100 surveys, for a copy of any of the reports, electronic or CD, please contact

Classification of shellfish harvesting areas and E.coli monitoring

Food Standards Scotland is responsible for ensuring that shellfish from designated harvesting areas meet the health standards laid down in EC Regulation 853/2004. Classifications are awarded according to the FSS Protocol for Classification and Management of E.coli results. Live bivalve molluscs (shellfish) harvesting areas are classified by monitoring the levels of E.coli in shellfish flesh.

Treatment processes are specified according to the classification status of the area.

Shellfish classification categories and permitted levels of E.coli/100g flesh:

Category Classification criteria Action
A 80% of the samples collected during the review period < 230 E.coli/100g of flesh and intravalvular liquid. The remaining 20% of samples < 700 E.Coli/100g of flesh and intravalvular liquid. May go directly for human consumption if end product standard met
B 90% of samples collected during review period < 4600 E.coli/100g of the flesh and intravalvular liquid. The remaining 10% of samples < 46 000 E. Coli/100g of flesh and intravalvular liquid. Must be subject to purification, relaying in Class A area (to meet Category A requirements) or cooked by an approved method
C Samples < 46,000 E.coli/100g of the flesh and intravalvular liquid. Must be subject to relaying for a period of at least 2 months or cooked by an approved method
above 46,000 E.coli/100g of the flesh and intravalvular liquid Prohibited. Harvesting not permitted


In addition, there is a legal requirement for food businesses to ensure the shellfish they harvest from classified waters are safe to eat. Therefore, before placing shellfish on the market, businesses must ensure that they comply with the health standards in Annex III of EC Regulations 853/2004 and the Microbiological Criteria adopted under EC Regulation 2073/2005.

The Classification of Shellfish Harvesting Areas in Scotland document 2016/17 has been finalised following the appeals process which is now complete for this year. The document will provide you with all current classified shellfish harvesting area details.

The classification document is divided by local authority area with the details of each classification area stipulated. Declassified production areas are noted in a separate report at the back of the document.

Each classification area has been provided with a Site Identification Number (SIN). It is essential that this number and a grid reference point (to the accuracy of 10 metres) are used on all laboratory sample submission forms. This is essential for the verification and management of sample results.

If you have any queries regarding the contents of these publications, please contact

Shellfish classification documents







For previous years classification documents (prior to 2011), you can visit The National Archive.

Classification protocol

The E. coli classification protocol outlines the procedure used by Food Standards Scotland to classify shellfish harvesting areas according to the requirements of EC Regulation EC 854/2004.

Use of Harvester's Own Results

Regulation (EC) 854/2004 allows for the results of samples collected by harvester to be taken into account for the purposes of OC decision making. These results will only be considered if taken in accordance with an agreed protocol.

Biotoxin monitoring programme

Marine biotoxins, which are produced by certain types of phytoplankton (marine algae), can accumulate in the tissues of filter feeding live bivalve molluscs (shellfish). The consumption of shellfish which are contaminated with these biotoxins can lead to illness, ranging from sickness and diarrhoea to more serious conditions which could require hospital treatment.

Food Standards Scotland monitors Scotland’s classified harvesting areas for the presence of marine biotoxin producing phytoplankton in waters and marine biotoxins in shellfish flesh. This programme identifies when there is an increased risk of shellfish becoming contaminated with biotoxins and when businesses will need to take appropriate steps to ensure the shellfish they are placing on the market do not contain unsafe levels. When legal limits of biotoxins in shellfish are breached, Food Standards Scotland and Local Authorities take action to ensure the affected areas are closed for harvesting.

The shellfish flesh monitoring programme, involves the sampling of shellfish from fixed monitoring points in inshore classified harvesting areas and additional sampling at commercial processors of wild pectinidae (scallops) which have been harvested from unclassified offshore waters. These samples are tested for three groups of biotoxins:

  • Paralytic Shellfish Poisoning (PSP) Toxins;
  • Amnesic Shellfish Poisoning (ASP) Toxins, and;
  • Lipophillic Shellfish Toxins (LTs), which include the toxins responsible for Diarrhetic Shellfish Poisoning (DSP); and Azaspiracid toxins (AZAs)

For more on the effects of these diseases, see our Foodborne Illness page.

In the phytoplankton monitoring programme, water samples are collected from fixed sites within selected harvesting areas and the composition of marine algae identified and enumerated.

Shellfish flesh monitoring

There are approximately 167 classified shellfish harvesting areas in Scotland. These areas are assigned to ‘pods’, where areas within a pod are thought to be similar hydrographically and environmentally.

For each pod, one of the areas is assigned a Representative Monitoring Point (RMP) status, with the remaining areas being assigned Associated Harvesting Area (AHA) status. For each RMP, a representative shellfish species (usually mussels) is sampled according to a set timetable based on risk assessment. Currently, samples of mollusc are collected from approximately 85 RMPs by shellfish sampling officers and submitted for flesh analysis. These samples are tested for three groups of algal toxins for which maximum permitted levels are set by the EU legislation - amnesic shellfish poisoning toxins (ASP), paralytic shellfish poisoning (PSP) toxins and lipophilic toxins (LTs) which include diarrhetic shellfish poisoning toxins; DSP), pectenotoxins, yessotoxins and azaspiracids.

Biotoxin levels

The maximum permitted levels of biotoxins in shellfish are:

Toxin group

Regulatory level

Paralytic shellfish poisoning (PSP) toxins

800 micrograms (µg) STX equivalents/kg

Amnesic shellfish poisoning (ASP) toxins

20 milligrams (mg) DA/kg

Lipophilic Toxins

Diarrhetic shellfish poisoning (DSP) toxins and Pectenotoxins (PTXs)

160 micrograms (µg) OA equivalents/kg

Yessotoxins (YTXs)

3.75 milligram (mg) YTX equivalents/kg

Azaspiracids (AZAs)

160 micrograms (µg) AZA equivalents/kg

The current frequency for sampling and testing for majority of pods is presented below:

  • PSP: either weekly, fortnightly or monthly, as determined by risk assessment;
  • LTs: weekly March to December, monthly January and February;
  • ASP: either weekly, fortnightly or monthly, as determined by risk assessment

For details of any Temporary Closure Notices and/or Warning Notices please contact your local authority environmental health officer. The absence of results for a harvesting area does not necessarily mean the area is free of biotoxins. Even when areas are open for harvesting, it remains the responsibility of food business operators to ensure that their products comply with all relevant statutory requirements.

Annual reports

For annual reports contact, or further information regarding harvesting or the interpretation of results, please contact your local authority for advice.

Get biotoxin alerts on Twitter or by text:

By text

If you are on the Orange, Vodafone, 02 or 3 networks, text 'follow FSScotBiotoxins' to 86444.

Please check with your mobile provider for information on charges.


If we get natural toxin results OVER the Max Permitted Level (MPL) for biotoxins we will tweet it! Follow FSScotBiotoxins on twitter

Phytoplankton levels

Water samples are collected from classified harvesting areas and analysed by light microscopy for various species of phytoplankton. Alert level phytoplankton concentrations have been set as per the table below and harvesters should take the necessary precautions if wanting to harvest under alert conditions.

Phytoplankton alert levels set by National Reference Laboratory network:

Biotoxin Phytoplankton Alert

PSP (Saxitoxin)


Equal to or greater than 40 cells/litre of Alexandrium


(Okadaic acid)

Dinophysis and Prorocentrum lima

Equal to or greater than 100 cells/litre of Dinophysis


Equal to or greater than 100 cells/litre of P. lima.


(Domoic Acid)


Equal to or greater than to 50,000 cells/litre of Pseudo-nitzschia

During the reporting period, monitoring frequency was set by the FSS as follows:

  • weekly for all sites between March and September;
  • fortnightly in October
  • monthly sampling from November to February in a limited number of selected areas, to reflect the low abundance of phytoplankton in the water column during the winter months.

Annual reports

For annual reports contact, or further information regarding harvesting or the interpretation of results, please contact your local authority for advice.

Scallops monitoring

Wild pectinidae (scallops) monitoring.

Food Standards Scotland controls all functions under EC Regulation 854/2004, which includes the regime for official controls on wild scallops. Enforcement of the regime is the responsibility of Local Authorities.

For more information, see the Official Controls of wild pectinidae for biotoxins implementation of EC regulations 854/2004 and 882/2004.

Chemical contaminants

Bivalve shellfish feed by filtering plankton from the surrounding water that washes through their habitat. This feeding mechanism can lead to the bio-accumulation of environmental pollutants such as dioxins, polychlorinated biphenyls (PCBs), heavy metals and polycyclic aromatic hydrocarbons (PAHs) from the surrounding waters. EU legislation defines legal limits to ensure the control of these contaminants in a range of foods including shellfish. In accordance with EU law, Food Standards Scotland manages the Official Controls chemical contaminants monitoring programme.

In this programme, shellfish flesh samples are collected from classified harvesting areas and analysed for heavy metals, dioxins, PCBs and PAHs. Levels should not exceed those laid out in EC Regulation 1881/2006, as amended.

The maximum permitted levels of chemical contaminants in shellfish:



Maximum level

(Wet weight)




1.0 mg/kg


0.5 mg/kg

Polycyclic Aromatic Hydrocarbons


5.0 µg/kg for Benzo(a)pyrene

30.0 µg/kg for sum of Benzo(a)pyrene, Benzanthacene, Benzo(b)fluoranthene and Chrysene

Dioxins and PCBS


3.5 pg/g sum of dioxins

6.5 pg/g sum of dioxins and dioxin-like PCBs

Annual reports

Annual report 2015

For further information regarding harvesting or the interpretation of results, please contact your local authority or for advice.

Guidance for industry

Our 'End-product testing for shellfish toxins' leaflet provides food business operators (FBOs) with the information they need to ensure appropriate implementation of end-product testing (EPT) for marine biotoxins in bivalve molluscs. The leaflet also explains how the different biotoxin testing methods work, lists their limitations and describes how they should be used as a part of the wider risk assessment process. Additionally, the document supplies detailed information regarding the current regulatory limits, list of other factors that should be taken into consideration in conjunction with the EPT, as well as a number of case studies – real life examples of situations where EPT results helped FBOs to demonstrate compliance with the regulations and to influence the monitoring programme.

Shellfish Toxin End-Product Test (Quick Reference Guide)

End-Product Testing for Shellfish Toxins

Managing Shellfish Toxin Risks: for Harvesters and Processors

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