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July 1, 2012

To: Registered Shellfish Processing Establishments in Atlantic Canada

Subject: Vibrio parahaemolyticus in Bivalve Shellfish - Update

The Canadian Food Inspection Agency (CFIA) is providing the following update and reminder regarding the management of risks associated with the consumption of shellfish contaminated with Vibrio parahaemolyticus. This notice is a continuation of communication with the shellfish industry (see previous notice) and provides additional information based the results of a survey conducted in 2011.

Vibrio parahaemolyticus (Vp) is a bacterium that naturally inhabits coastal waters of Canada and the United States, can be found in higher concentrations during summer as water temperatures rise, and can cause gastrointestinal illness in humans. Vp can be present in any shellfish growing area regardless of the classification established by the Canadian Shellfish Sanitation Program (CSSP).

In response to the four isolated, confirmed Vp illnesses in 2010, the CFIA conducted a survey of 11 sites in NS, NB and PEI in 2011. It was found that, generally, Vp levels begin to rise in July and peak around mid August, coinciding with peak water temperatures. These results are consistent with previous studies conducted by the CFIA in 1998 and 2005. It is important to note that Vp levels in oysters can increase rapidly if appropriate time/temperature controls are not implemented following harvest, thus increasing the risk of Vp illness.

Given that Vp is present in Atlantic Canadian waters during the summer, it is important that harvesters, growers and processors are aware of the potential risks with Vp and implement appropriate controls from June until September, where necessary. Some of the control measures to consider include but are not limited to, the following:

  • Ensuring that shellfish are handled to comply with schedule III and V of the Fish Inspection Regulations by:
    • keeping harvested shellfish submerged or cooled until delivery to the registered processing establishment;
    • avoiding overnight holding of shellfish without refrigeration/icing; and
    • having minimal transit times between the harvest area and registered processing establishment when refrigeration/icing is not practical.
  • Having processors identify, document and implement Quality Management Plan (QMP) Vp controls where necessary by:
    • ensuring prompt refrigeration, wet storage or processing upon receipt at registered processing establishments; and
    • maintaining temperature control through processing steps.

The CFIA will conduct routine compliance verifications at registered processing establishments and will be assessing QMP plans to ensure that appropriate controls are implemented where necessary.

Any questions or comments regarding the above can be directed to your local CFIA Fish Inspection office.


Terence McRae
Fish, Seafood and Production Division

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