Fish and Shellfish Safety

Food Safety: Information for First Nations
ISBN: 978-1-100-20095-8
Catalog: H34-246/1-2012
Publication: 120026

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Fish and shellfish are an excellent source of nutrition, and provide an important source of protein, iron, B vitamins and omega-3 fatty acids. They are also high in essential minerals and low in calories, saturated fats and cholesterol.

While fish and shellfish are good for your health, they may be exposed to germs and natural toxins such as biotoxins, which can build up in their flesh. Fish and shellfish living in waters near sewage treatment plants, community sewage pipes that empty into waterways, and those harvested during certain periods or in areas prone to harmful algal blooms are at risk of being contaminated.

Eating contaminated fish and shellfish can make you and your family sick. Potential health risks from eating contaminated fish and shellfish may include:

• Diarrhea
• Paralysis
• Memory loss
• Blurred or double vision
• Occasionally death

Fish can also be a source of exposure to various chemical contaminants such as pesticides, industrial or natural chemicals including dioxins and mercury. These contaminants accumulate in fish through contaminated foods which are present at low levels in fresh waters and oceans. Levels of contaminants are generally highest in the older and larger predatory fish and marine mammals.

Some germs can accumulate in bivalve shellfish (i.e., oysters, clams, and mussels) because they feed by filtering water. As a result, bivalve shellfish can also accumulate certain marine toxins in their tissues. This can cause serious illnesses such as Paralytic Shellfish Poisoning (PSP) in people who consume them.

While cooking may kill bacteria, viruses and parasites that may be present in fish and shellfish, it does not destroy marine toxins found in bivalve shellfish, or other contaminants in fish and shellfish.

Pregnant women, young children, the elderly, and those with a weakened immune system are more likely to experience a severe illness if they get shellfish or fish poisoning. Consult a health care provider or go to a health centre if you think you have shellfish or fish poisoning.

Minimize the Risk – Protect Yourself and Your Family

Here are some simple things to do to make sure that the fish and shellfish you bring home are safe to eat.

Fishing

• Obtain your fish from an approved supplier.
• Do not eat fish from waters known to have high levels of contaminants.
• Follow local, provincial, and territorial sport fish consumption advisories.
• Choose smaller fish, as older and bigger fish tend to accumulate more contaminants.
• Keep fish and shellfish on ice in a cooler until they can be refrigerated or cooked; if not cooled, fish and shellfish should be cooked and eaten within 2 hours of catching.
• Do not mix different types of fish, use plastic bags to separate the different types of fish in the cooler.

Harvesting Shellfish

Bivalve shellfish such as clams, oysters, mussels and cockles are sensitive to the quality of the water. Harvest fish and shellfish only in designated open harvest areas. When in doubt, don't harvest.

• Shellfish should not be harvested within any area designated as "closed" or within 125 metres (400 feet) of a wharf, as these areas are considered to be contaminated.
• Harvest shellfish at least 300 metres (1000 feet) away from sources of pollution, sewage treatment plants or community treatment plants.

Preparing

Fish and shellfish spoil very quickly if they are not handled properly. Here are some things you can do to reduce risks during preparation.

• Wash hands well with soap and warm water to a slow count of 20 before and after handling food, after using the bathroom, changing diapers, and handling money and pets.
• Defrost fish and shellfish in the refrigerator overnight and use within a short period of time (approximately 12 hours).
• Use a separate cutting board for fish/shellfish and another for ready-to-eat foods.
• Trim the fat from fish before cooking.

Storing

• Store cooked and uncooked fish and shellfish at 4°C (40°F) or lower or freeze at -18°C (0°F) or lower.
• Keep live shellfish covered with wet cloths or sacking to retain moisture.
• Separate cooked and uncooked fish and shellfish to avoid cross-contamination.
• Cooked shellfish should be used within 3 days.

Cooking

Fish

• If you eat fish raw, you should freeze it first for at least 7 days at -20°C (-4°F) to kill any parasites that may be present. This will also prevent germs from growing.
• Cook fish using methods that allow the fat to drain, such as broiling, baking, boiling or grilling.
• When you cook fish, the internal temperature should reach at least 63°C (146°F).
• Drain and throw away any excess fat after cooking.

Shellfish

Cook fresh shellfish as soon as possible to recommended temperatures to kill any germs that might be present, and make sure that fresh shellfish are alive prior to cooking (normally the 2 halves of bivalve shellfish should be tightly closed; if they are gaping, discard).

• Boil: Add shellfish to boiling water and keep boiling for an additional 3 to 5 minutes after the shells open.
• Steam: Steam for 4 to 9 minutes in a steamer.
  Note: Boil and steam shellfish in a single layer for even heating.
• Bake: Bake in a preheated oven for at least 10 minutes at 230°C (450°F).

Discard any shellfish that do not open once cooked.

Recommended Storage Times for Fish and Shellfish

Food	Refrigerator (4°C/40°F)	Freezer (-18°C/0°F)
Opened canned fish or seafood	1 day	Not recommended
De-shelled (shucked) clams, mussels, oysters, and scallops	1-2 days	3-4 months
Live mussels and clams	2-3 days	Not recommended
Live oysters	7-10 days	Not recommended
Cooked fish	1-2 days	1 month
Cooked shrimp	3-4 days	3 months
Raw crab	1-2 days	2 months
Cooked crab	3-5 days	2 months
Fatty fish: mullet, ocean and sea perch, char, sea trout, striped bass, salmon, mackerel, and tuna	1-2 days	2-3 month
Fresh lean fish: cod, flounder, haddock, halibut, and perch	1-2 days	4-6 months
Fillets - fresh water fish	1-2 days	6-9 months
Lobster	1-2 days	6-12 months
Salmon steak	1-2 days	2 months
Shrimp	1-2 days	6-12 months
Smoked fish	1-2 weeks	4-5 weeks

Recommended Storage Life for Frozen Fish

Fish	Recommended period for storage
Salmon, char, and trout	3 months
Cod, pike, and fish fillets	6 months
Northern pike, lake trout, and smelt	4 to 6 months
Bluegills, bass, crappies, and sunfish	7 to 9 months
Walleye and yellow perch	9 to 12 months

For more information talk to your local Environmental Health Officer or visit HealthyCanadians.gc.ca/FirstNationsFoodSafety.