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CHAPTER 10 - POLICY AND PROCEDURES FOR CONTROLLED RELAYING AND DEPURATION

(Please see Section 1 - Introduction for Adobe download file)

10.2 Depuration Facility Protocol

All companies planning to develop a depuration system or presently engaged in depuration must conform to the requirements of the QMP and the criteria contained in the following sections.

10.2.1 Harvest Areas

Overlay waters must have median or geometric mean faecal coliform counts not exceeding 88 MPN/100 mL, not more than 10% of samples exceeding 260 MPN/100 mL, based on Environment Canada surveys and recommendations (see Chapter 2, Section 2.3.3.1).

10.2.2 Processing Water and Facility Requirements

The following are intended as guidelines. Any deviations from the following may be made only after discussion with CFIA and when their efficacy has been proven through verification.

a) Water

Processing water is required to meet or exceed the following minimum requirements:

1. the water must be from a source approved by CFIA;
2. water from sources vulnerable to contamination must undergo bactericidal treatment resulting in an absence of total coliforms/100 mL (defined as <2 total coliforms/100 mL). Protected sources, i.e., drilled wells, that consistently meet the standard need not be treated;
3. the oxygen* content shall be at least 5 ppm or 50% saturation;
4. the salinity* shall be ± 20 % of the median salinity regime of the area where the bivalve molluscs are harvested, unless salinities outside this range are established as a result of the scheduled depuration process evaluation;
5. the turbidity* shall be less than 20 Jackson Turbidity Units (or equivalent Nepholometar turbidity units);
6. the temperature* shall be adequate to permit normal metabolic activity of bivalve molluscs, the limits to be determined by process evaluation;
7. for closed or recirculating systems, the ammonia level of process water must remain below 0.9 ppm;
8. there shall be no undesirable chemicals or other substances which may affect pumping of bivalve molluscs; and
9. marine biotoxin contamination in shellfish during depuration must not exceed the levels identified in Chapter 11.

Note: The criteria marked * may be naturally variable at different locations.

b) Facility

All facilities must meet the following minimum requirements:

1. all buildings (including storage) must conform to sections of the Fish Inspection Regulations (FIR) including, but not limited to, sections 6(1), 14(1), 15(1), 16, 20 - 23 and Schedules I and II;
2. storage facilities must be designed to maintain physical separation between shellstock to be depurated and other shellstock (depurated and approved area harvests); and
3. adequate washing and culling facilities must be present.

c) Off-site Storage

Note: Prior to depuration, pre-process shellstock may be held in wet storage (in near-shore intertidal/subtidal areas). Such wet storage helps provide sufficient inventory for the depuration facility and also allows the shellfish to acclimate to the local seawater conditions in which they will be depurated.

If wet storage of pre-process shellstock is carried out off site (separate location from the main registered establishment), the operators must ensure that:

1. control and oversight is maintained over such storage locations, that all potential hazards associated with storage are considered, and that these are incorporated into the QMP of a registered establishment;
2. vehicles and equipment used to transport shellfish from the storage facility to the main establishment meet the requirements of Schedule III and Schedule V of the FIR;
3. restricted access to stored shellfish is maintained; and
4. records are maintained at the registered establishment which permit CFIA officials to identify lots at the storage area.

Refer to sections 10.2.5 (c) and (d) for further storage considerations.

d) Tanks

Tanks shall be:

1. constructed of corrosion resistant, non-toxic, non-absorbent, and easily cleaned material;
2. self-draining to facilitate cleaning;
3. easily accessible for cleaning and inspection;
4. maintained in good repair;
5. able to maintain a minimum flow rate of 107 litres per minute per cubic metre of shellstock. The above criteria are equivalent to 1 U.S. gallon per minute per U.S. bushel (1.24 cubic feet);
6. constructed so as to provide adequate water flow throughout the tank (so that shellstock has adequate access to incoming clean water);
7. constructed to ensure they contain water and shellstock at a minimum volume ratio of 4:1 (equivalent to 142 litres of water per 35.24 litres shellstock, or 5 cubic feet of water per U.S. bushel) for soft clam, and water and shellstock at a minimum volume ratio of 6.4:1 (equivalent to 227 litres of water per 35.24 litres shellstock, or 8 cubic feet per U.S. bushel) for hard clams (Manila and littleneck) and oysters. Limits for other species would be determined with CFIA during scheduled process evaluation); and
8. constructed such that there is sufficient volume to permit a minimum of 7.6 centimetres (3 inches) of water clearance around each container. This spacing is necessary to provide for uniform water flow through and around processing containers.

e) Processing containers

Processing containers shall be:

i) constructed of corrosion resistant, non-toxic, non-absorbent, easily cleanable material; and

ii) of a suitable size and shape to permit:

1. a mid-cycle washing of shellfish;
2. an adequate flow of water to all shellfish;
3. a maximum depth of Manila and littleneck clams of 10 cm (4 inches);
4. a maximum depth of soft-shelled clams in containers of 20 cm (8 inches); and
5. a maximum depth of 30 cm (12 inches) in Pacific oysters, 10 cm (4 inches) in Atlantic oysters and hard-shelled clams.

The loading criteria for other species would have to be determined by experimentation.

Note: Deviations from these criteria may be allowed only if process verification studies (see 10.2.7) show that the depuration process consistently yields bacteriologically acceptable product.

f) Water treatment

A water system is installed to provide an adequate quantity and quality of water for the controlled purification process. Any treatment must not leave residues that may interfere with the process. The quality of the incoming water prior to any disinfection shall meet or exceed the requirements for restricted areas for controlled purification (see 10.2.1). In North America an ultraviolet light (UV) system is the most common method of marine water treatment. Other methods may include chlorination/dechlorination or ozonation/deozonation.

Ultraviolet tubes must be regularly checked for intensity and must be replaced as prescribed by the manufacturer.

If, prior to UV treatment, water turbidity exceeds limits [see 10.2.2 a)v)], sand filters or the equivalent may be used as a pre-treatment. The requirements of the UV system for pre-treatment must be checked at the time of installation. The manufacturer of sand filters should be consulted for proper maintenance and the turbidity checked regularly (validation data are required).

An automatic shut off is required (which may be connected to a UV sensor to ensure light efficiency) before or after the ultraviolet system or other means to ensure that untreated water does not enter the tanks in the event of power or ultraviolet system failure. If the shut down was significant and/or the water level drops below the level of any shellstock in the tank, in a self-draining system, then the cycle must restart at the beginning of that 24-hour cycle. The time for a shut down to be significant is determined on a system-by-system basis and must be documented in an establishment’s QMP.

(WARNING: It is dangerous to look directly at ultraviolet bulbs without eye protection. Signs stating this danger should be prominently displayed.)

Biological filters are also common equipment in recirculating systems. They are needed to reduce ammonia to acceptable levels and to remove waste metabolites. The manufacturer of biofilters should be consulted for proper maintenance.

10.2.3 Shellstock Separation Requirements

The handling and wet storage of approved area bivalve molluscs is permitted at a depuration facility if the control for separation in time and space of depurated and approved area bivalve molluscs is documented and controlled so that there is no chance of mixing.

10.2.4 Laboratory

Any laboratory used to perform the necessary analyses is required to be approved by a Lab Evaluation Officer.

The requirements that microbiology and bioassay laboratories must meet are described in checklists found in Appendix I (Annex I - CSSP Microbiology laboratory evaluation checklist; Annex II - CSSP Bioassay laboratory evaluation checklist [to be issued at a later date]).

10.2.5 Operational Controls

a) Harvesting Controls

i) Harvesting areas will be designated and/or assigned by the appropriate DFO office.

ii) A harvesting plan must be submitted to the appropriate DFO office and approved prior to the harvest. It shall contain:

1. the names of all harvesters;
2. the exact location in which they will be digging; and
3. the exact date of each harvest.

iii) Each lot of shellfish must be identified and maintained physically separate.

iv) At the time of harvesting, all containers of shellfish in a lot must be properly identified and the records shall show:

1. the date of harvest;
2. the area of harvest;
3. the harvester's name;
4. the quantity harvested by each harvester; and
5. the harvest license number

These records must be maintained and available for review.

v) A designated "Master Harvester" will be responsible for supervising the harvesting and maintaining the identity of the lot to the storage facility or depurator.

b) Transport

The shellfish must be transported from the harvest area to the storage area and/or to the depuration facility in a manner approved by CFIA and meet the requirements of Schedule V of the Fish Inspection Regulations (FIR). At no time shall product destined for depuration or relay be transported with product from Approved areas.

c) Dry Storage at a Registered Facility

i) It is recommended that as short a time as possible elapse between the time of harvesting and the onset of depuration. In no case shall pre-process dry storage of shellfish exceed three days from the date and time of harvest to the date and time of the start of the depuration process. Water spray or mist over shellstock in dry storage is permitted. The system must be designed to prevent contamination to the shellstock.

ii) Storage temperature of bivalve molluscs prior to depuration shall not be:

1. greater than the temperature of the process water; and/or
2. more than 3 degree C below the process water temperature.

iii) Post-process storage temperature shall not exceed 4 degree C.

d) Wet Storage Off-Site

Bivalve molluscs may be held for up to 21 days in wet storage prior to depuration, providing:

1. the storage area meets the growing area classification for depuration (10.2.1);
2. the location is designated in the harvest license and is under constant supervision to prevent theft; and
3. the system is not in the verification phase.

d) Handling

1. Shellfish shall be washed and culled prior to depuration. During this procedure, shellfish shall not be mishandled or subjected to thermal shock. The quantity of culled shellfish and the method of disposal shall be recorded.
2. A tank shall not contain more than one harvest lot of bivalve molluscs.

e) Container Sanitation

1. Between depuration cycles, containers and depuration tanks shall be scrubbed clean, disinfected (with approved disinfectant), and rinsed to ensure no residue remains.
2. Tanks of bivalve molluscs shall be thoroughly hosed down at the end of each 18-24 hour period in the depuration cycle, in a manner which will not contaminate the shellstock.

10.2.6 Records

Up-to-date QMP records must be maintained at all times and must be available for QMP Compliance Verification. A listing of record types may be found in Annex 10A.

All forms used to record data must be included in the depuration protocol for approval before being used (examples of some forms are included in Annex 10B).

10.2.7 Process Verification

The facility must prove with a minimum of 20 lots that the depuration process is consistently cleansing the shellfish. In this assessment, each lot used must have 0 hr. results greater than or equal to a geometric mean of 230 faecal coliform/100 g, with no sample < 100. The number and location of samples to be drawn at zero, twenty-four, and forty-eight hours will be approved by CFIA. These samples may be taken over a number of tanks if these tanks are identical in all characteristics such as flow and dimensions. The services of an independent statistician may be used. The intent of these samples is to determine that all locations in the tank facilitate depuration.

The maximum zero hour limit for depuration of not less than 48 hours will be 2,300 faecal coliforms/100 g. If the system can consistently cleanse shellfish with higher zero hour faecal coliform counts, an approved Modified Schedule of not less than 72 hours may be used. CFIA will establish a depuration cycle time and maximum faecal coliform level for each individual system, based on facility performance. Sampling plans to adjust these parameters post-process verification must be approved by CFIA.

The depuration system will be considered to be working satisfactorily under defined processing parameters when faecal coliform analyses of samples of depurated bivalve molluscs meet the criteria as listed in Table 10.1. All sample locations in the tank must be shown to be equally effective in depurating shellstock.

Table 10.1 End Product Standards For Overall Depuration
Facility Performance Evaluation
(Faecal coliforms/100 g)

* Upper 10 percent level is where no more than 10 percent of the samples’ results used in the evaluation may exceed the value established as the upper 10 percent level for each species.

During the evaluation period the product may be released, by CFIA, to the market upon receipt of acceptable final hour bacteriological results as indicated in Table 10.2. Product that underwent a Modified Schedule will not be released to market during the evaluation phase, and may be relayed to a closed area. All shellstock must be clearly identified as a depurated product at all stages of marketing. It is the processor’s responsibility to ensure that buyers are aware of conditions for marketing depurated products (labelling and repacking restrictions).

Any final hour failures during the verification phase should be examined for cause and any proposed changes to the process or protocol as corrective action must be reviewed with CFIA. Product must be disposed of as per 10.2.10.

Changes to existing depuration facilities or the defined process parameters may require a complete re-evaluation of the system (examples are changed water flow, tank size, and density loading). The addition of identical tanks and systems in existing facilities with an approved process do not require re-evaluation on approval from CFIA.

A written report with all data and parameters from the verification must be prepared and a copy sent to CFIA. An additional copy shall be retained by the establishment.

10.2.8 Routine QMP Monitoring (Post-Verification) - Requirements

The processor must meet the following requirements:

a) Shellstock samples for bacteriological analysis must be taken from every lot at zero hour and at the final hour of depuration. Lots must meet the zero hour requirement (less than or equal to 2300 faecal coliform/100 g or more for a modified schedule as validated at 10.2.7) and final hour limits stated in Table 10.2.

b) The minimum number of samples to be analysed from each lot at 0 hours and 48 hours (or at completion of depuration) can be determined by the history of the performance of the depuration process, size of the lots depurated, the variation of the harvest area or areas, whether spatial or seasonal, and the initial levels of contamination.

A depuration facility which has high overall depuration performance and beaches with consistently low zero hour results, and is processing relatively small lots may, with CFIA approval have the number of zero and/or final (48-hour) samples reduced to 1. If such a facility were to find higher levels of initial faecal coliforms, experience deviations in final product results, or receive product from a new area, 5 zero hour samples would be required.

A facility which consistently shows initial faecal coliform counts of greater than or equal to 1000, receives product from diverse harvest areas, receives product from areas which experience wide fluctuations in contamination over time, would be required to analyse five (5) 48- hour samples.

If a modified schedule (72 hours) is used, five (5) final hour samples must be analysed.

Table 10.2 End Product Standards for Each Process
Batch of Shellfish (Faecal coliforms/100 g)

c) Samples of depuration water for bacteriological analysis must be taken at a frequency of at least one per day.

The depuration facility must keep records of all bacteriological results.

10.2.9 Process Deviations

Any process batch which shows a final hour faecal coliform count greater than 170/100 g for softshell clams or 100/100 g for all other shellfish will be considered as a BATCH DEVIATION. If two consecutive process batches have counts greater than 130/100 g for softshell clams or 70/100 g for all other shellfish, this will indicate a PROCESS DEVIATION. In either case, all information pertaining to the deviation shall be placed in a deviation file. The establishment must notify the CFIA Inspection Office immediately upon discovery of the deviation, and must initiate investigative action to determine the cause(s).

For lots that do not meet the zero hour requirement (less than or equal to 2300 faecal coliforms/100 g or as approved during process verification) or final hour limits (Table 10.2), the following options are available:

a) depurate using an approved Modified Schedule:

1. Lots with any zero hour result > 2300 may be purified using an approved Modified Schedule of not less than 72 hours. The lot shall be detained until the results of bacteriological analysis are complete. The lot will be released if the final hour results do not exceed the species limits in Table 10.2. If results exceed the species limit, the lot may be re-depurated using an approved Modified Schedule.
2. Lots with final hour results which exceed limits in Table 10.2 may be purified by using an approved Modified Schedule of not less than 72 hours in addition to the original depuration cycle. The lot shall be detained until the results of bacteriological analysis are complete. The lot will be released if the final hour results do not exceed the species limits in Table 10.2. If results exceed the species limits, the lot will not be re-depurated, unless it is first returned to a closed area for at least 14 days;

b) heat process (e.g., canning) the bivalve molluscs if the faecal coliforms are < 4000/100 g;

c) return to a closed area meeting the requirements of section 10.2.1. Product may not be re-harvested for depuration for at least 14 days;

d) have shellstock disposed of for other than human consumption.

Establishments are required to include overall depuration facility performance as evaluated using Table 10.1 in their Quality Management Plan self-verification.

Note: The end products of depuration operations must meet the guidelines as listed in Appendix II.

10.2.10 Product Release

Product that meets the final hour limits in Table 10.2 may be released to market. Product shall remain under the control of the establishment until released. During process verification, the product may be released, by CFIA, to the market upon receipt of acceptable final hour bacteriological results as indicated in Table 10.2. Product that underwent a Modified Schedule will not be released to market during the process verification, and should be returned to a closed area.

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