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The identification, analysis and control of hazards that present a risk of contamination of live shellfish

Although the Safe Food for Canadians Regulations (SFCR) came into force on January 15, 2019, certain requirements may apply in 2020 and 2021 based on food commodity, type of activity and business size. For more information, refer to the SFCR timelines.

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Introduction

The purpose of this document is to provide information on the hazards that can be present in live shellfish and some example control measures that could help prevent or reduce the risk of contamination of the shellfish. This is not intended as an exhaustive list of measures. Always ensure that the control(s) chosen are tailored to the uniqueness of your business and shown to be effective for your situation.

Hazards

Biological hazards

Pathogens can be found in the waters of the shellfish harvest, wet storage or relay areas and can present a risk of contamination of the shellfish. The shellfish can accumulate and become contaminated with the pathogens when filtering the surrounding water to feed. The presence of these pathogens in shellfish consumed in a raw or partially cooked state can present a risk of injury to human health.

The pathogens can be naturally occurring or the result of contamination by human or animal fecal matter. Naturally occurring pathogens include bacteria such as:

Pathogens from human and animal fecal sources include bacteria and viruses such as:

Example sources of pathogens include:

Natural Toxins

Natural toxins can be found in the waters of the shellfish harvest areas and can present a risk of contamination of the shellfish. Most of these toxins are produced by naturally occurring marine algae (phytoplankton). The toxins can accumulate in shellfish when they filter the water to feed on the algae. Natural toxins cannot be reliably eliminated by heat treatment (cooking) so their presence in shellfish consumed in a raw or cooked state can present a risk of injury to human health.

The natural toxins that can be found are:

Environmental Chemical Contaminants and Pesticides

Environmental chemical contaminants and pesticides can be found in waters of the shellfish harvest areas and can present a risk of contamination of the shellfish. Chemical contaminants cannot be eliminated by heat treatment (cooking) so their presence in shellfish consumed in a raw or cooked state can present a risk of injury to human health.

Chemical contaminants include:

Example sources of chemical contaminants include:

Control measures

The hazards that can present a risk of contamination of the shellfish need to be controlled with measures that are shown by evidence to be effective.

Controls at the harvest site

Control measures to prevent the harvesting of shellfish contaminated by pathogens, natural toxins and environmental contaminants are administered by Government authorities. In Canada, the control measures are jointly administered by the Canadian Food Inspection Agency (CFIA), Environment and Climate Change Canada (ECCC) and Fisheries and Oceans Canada (DFO) under the Canadian Shellfish Sanitation Program (CSSP).

Under the CSSP, the water quality in shellfish growing and harvest areas is surveyed to identify actual and potential sources of pollution. The areas are classified as to their suitability for the harvesting of shellfish according to accepted water quality standards and general sanitary conditions in the shellfish area. The levels of natural toxins are monitored to control the harvesting of toxic shellfish. The CSSP provides information about the shellfish areas that are open or closed to shellfish harvesting.

Shellfish can only be harvested in contaminated areas when a license, under the Management of Contaminated Fisheries Regulations, has been issued to harvest the shellfish and the shellfish are decontaminated using an approved depuration or relay operation. Refer to to the document Depuration of bivalve shellfish and section 9.4.2 of the CSSP manual

For areas subject to a conditional management plan, based on the operation of a waste water treatment plant, shellfish can only be harvested inside the response line identified on the classification map.

Control measures to reduce the risk of Vibrio parahaemolyticus in live oysters are discussed in the document Measures to control the risk of Vibrio parahaemolyticus in live oysters.

Control measures applied by an operator

Control measures to prevent harvesting or sourcing of contaminated shellfish should ensure that the shellfish are sourced from:

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