Wet storage of bivalve shellfish

On this page

• Introduction
• Definitions
• Source of shellfish for wet storage
• Onshore wet storage systems
• Outdoor wet storage systems
• Nearshore wet storage
• Record keeping

Introduction

This document provides information for licenced operators that are conducting wet storage. It covers recommended considerations and practices when developing and implementing a preventive control plan for this activity. Further guidance can be found in The identification, analysis and control of hazards that present a risk of contamination of live shellfish.

Definitions

Please refer to the Canadian Shellfish Sanitation Program manual for definitions.

Source of shellfish for wet storage

Shellfish for wet storage are harvested from approved or conditionally approved shellfish harvest areas (hereafter referred to as areas) in open status.

Onshore wet storage systems

Shellfish is wet stored in systems with continuous flowing water. Avoid storage in standing water.

Water quality

• When wet tanks are set up and operated as a re-circulating system, the water is treated.
• When synthetic seawater is used, it is manufactured from water meeting the requirement of ≤ 2 coliforms/100 mL. Salt added shall be food grade.
• When wet storage tanks are set up and operated as a flow-through system, the source water:
  • is from an area that is classified as approved or conditionally approved and in open status, or
  • meets the bacteriological water quality criteria of an approved area as demonstrated by the proponent upon start up, and on a regular basis - if the source water is from an unclassified shellfish area.
  • is treated - if the water originates from an area classified as restricted, or conditionally restricted, or does not meet the criteria outlined above,
  • is not from a prohibited area.
• Water is not used in an onshore flow-through wet storage system if the source area is in closed status unless:
  • a validated treatment/filtration system is in place to eliminate or reduce microbiological or biotoxins hazards to an acceptable level, and
  • the source area is not in closed status as a result of a wastewater treatment system malfunction or bypass.

Water treatment and filtration systems

As part of operating validated water treatment and filtration systems, the ongoing monitoring and verification of the effectiveness of each system should consider the following. This is not intended to be an exhaustive list of control measures.

• For systems using UV treatment, UV intensity, turbidity and water flow rate meet the manufacturer's specifications for treatment.
• For water receiving UV or ozone disinfection, the turbidity meets the manufacturer's specifications. In the absence of manufacturer specifications, turbidity is not greater than 20 Nephelometric Turbidity Units.
• For systems using ozone treatment, there is no free ozone in water that comes into contact with shellfish
• Ozone is used under good manufacturing practices to avoid hazardous compound formation such as bromate.
• Post-treated water is verified on a regular basis to be ≤ 2 coliforms/100 mL.

Shellfish handling

• Shellfish are washed and culled to remove dead, broken, or cracked shellfish prior to wet storage in tanks. Culling of mussels may be done after wet storage due to the adverse effects of culling on mussel physiology.
• Shellfish lot identity is maintained. Shellfish from different harvest lots are not commingled during wet storage in tanks.
• Bivalve shellfish are not stored with other non-bivalve species in the same tank.
• Where multiple tank systems use a common water supply system for bivalve shellfish and other non-bivalve species, the water is:
  • treated prior to being used to fill tanks containing the bivalve shellfish, or
  • supplied to the tanks containing the bivalve shellfish first.

Tanks and plumbing

In addition to minimum requirements for establishments and equipment found in the Safe Food for Canadians Regulations (Part 4 - Preventive Control Measures) tanks and plumbing are:

• constructed so as to be easily accessible for cleaning and inspection,
• self-draining or equivalent (e.g. an alarm installed or a backup system).

Outdoor wet storage systems

All wet storage tanks are covered and the covers:

• are designed to prevent entry and contamination by birds, animals or vermin,
• remain closed while the system is in operation except for periods of tank loading and unloading, cleaning, or monitoring and verification activities.

Nearshore wet storage

• The location of the storage site is in an area classified as approved or conditionally approved.
• Shellfish are only removed from a nearshore wet storage site when the area is in open status.
• If shellfish are stored in containers, the containers are constructed and loaded to ensure the free flow of water to all shellstock.

Record keeping

There is a clear indication of the harvest and wet storage history of the product in the records maintained by the licenced operator.