by: Marjorie Day
Family Living Agent, Retired
Preserving seafood is serious business whether you are angling Washington's deep waters for prize finfish or harvesting succulent shellfish from tidelands. Extending the enjoyment of your labors becomes important when considering time and financial resources necessary to bring home a catch.
When harvesting shellfish, close attention needs to be paid to beach closures. A number of toxins, bacteria and viruses are associated with shellfish, which when consumed, can cause serious illness, permanent memory loss, and occasionally death. Harvest all seafood from designated safe waters and beaches. In Washington a toll-free hotline provides information on locations closed due to pollution. The number is 1-800-562-5632.
Time is of an essence to assure seafood quality. Once finfish or shellfish leave the marine environment deterioration is rapid. Keep temperatures surrounding fish and shellfish as close to 32°F as possible.
Many long treasured recipes and techniques in use today may not meet the requirements for a safe seafood product. This handout provides procedures to assure a safe and quality product.
Food preservation bulletins pertaining to seafood are available at the Cooperative Extension office in your county. Basic directions and processing details are provided in each bulletin. Some of these bulletins are not preservation bulletins but contain information relating to preparing seafood for table use. Click here to order WSU Food Safety Publications on-line.
Canning Seafood- (PNW 194)
Home Canning Smoked Fish - (PNW 450)
Smoking Fish at Home Safely- (PNW 238)
Freezing Meat, Fish, and Poultry at Home - (EB 1195)
Fish Pickling for Home Use - (PNW 183)
Seafood Safety - National Fisheries Institute
Keep It Cool
When finfish and shellfish are removed from marine waters or beaches they are subject to rapid bacterial growth if not chilled immediately.
Quality fish are those that are eviscerated (gutted) immediately and kept in an ice filled cooler with additional ice placed in the belly cavity. Fish have better flavor if the gills and tail are removed to encourage free bleeding.
Large numbers of bacteria inhabit the intestines of fish in addition to potent digestive enzymes. These enzymes continue to act after the fish dies allowing bacteria access to the belly walls where the flesh becomes red and burned.
Try to limit physical damage while landing fish. Punctures and cuts give bacteria access to inner portions of edible flesh. Do not leave fish exposed to sunlight.
Carry large fish by hooking fingers into the empty gill slit. Handling large fish by the tail can rupture blood vessels allowing them to leak blood into adjacent flesh.
Transport all whole fish, chunks or fillets covered with generous amounts of ice in a cooler. A chest fitted with a bottom rack keeps fish separated from melted water and fish drippings.
Shellfish also benefit from cool temperatures. When transporting, place shellfish in a bucket or other open container and cover with a thick layer of clean, wet, cloths. At home keep them well ventilated, loosely covered and refrigerated. Never store in a sealed or closed plastic bag.
Keep shellfish alive until ready to preserve or consume. Shellfish soon suffocate and die when kept in a bucket of water or closed container. Shells of live clams, mussels and oysters may gape but will close tightly when tapped, indicating they are still alive and safe to consume. Refrigerate live shellfish no longer than five days before consuming.
Preserving the Catch
- Use of a pressure canner is the only safe method for canning seafood. Follow recommended canning times exactly to assure a safe product.
- Use 11# pressure on a dial gauge, 10# pressure on a weighted gauge canner when canning at sea level. Check seafood bulletins for pounds pressure adjustments when canning at altitudes over 1000 feet. Pounds pressure differ for weighted and dial gauge canners.
- Use only pint or half-pint jars for canning seafood. Safe processing times have not been determined for quart jars or metal cans.
- Use special instructions for smoking fish intended for canning. See Home Canning Smoked Fish - PNW 450.
For best quality and longer storage time fish fillets, roasts or whole fish benefit from a glaze of ice. After cleaning and cutting fish to size, lay each portion on a tray allowing enough space between portions so they do not touch. Lining the tray with wax paper or aluminum foil for easy of removal is optional. Set each filled tray into freezer.
When fish is completely frozen, usually several hours, remove from freezer. Dip each piece into cold (34-36° F) water. Return to tray and freeze a second time. Repeat the dipping and freezing process several times more to obtain an impenetrable glaze of ice. Now the fish is ready for a permanent wrap. Aluminum foil, freezer paper, or sealed bags all work well when as much air as possible has been removed. Vacuum sealers are very efficient at air removal from packages.
Under the best of conditions, fish have a very short storage life in the freezer before rancidity affects flavor. Refer to Freezing Meat, Fish and Poultry at Home, EB 1195, for additional information.
Fresh Fish And Shellfish These products require refrigeration for safe keeping. For optimum flavor and eating enjoyment prepare and serve within one or two days of harvest.
Smoked Fish And Shellfish Smoked fish and shellfish must be kept refrigerated or frozen (unless specially heat-processed as described in the following paragraph.) Use refrigerated smoked products within 2 weeks or keep frozen. This recommendation applies to both home-smoked and commercially prepared fish, including smoked fish in heavy plastic vacuum-sealed packages.
Some commercially processed smoked fish can be stored at room temperature. This type of smoked fish is first sealed in a foil pouch that can withstand high heat; then is heated to the same temperature used for canning fish. (In other words, the fish is canned, in the foil pouch rather than in a can or jar.) This process cannot be duplicated in the home kitchen.
These foil packages of smoked fish, which can be stored at room temperature, are more expensive than other smoked fish and are most frequently sold in gift shops or specialty food stores. They will be labeled; "This product does not require refrigeration prior to opening". After opening, keep in the coldest part of the refrigerator and use within 2 weeks.
Pickled Fish Store pickled fish in the refrigerator and use within 2-3 weeks.
The primary purpose of smoking is not to preserve the fish but to add flavor and color. Directions given in Smoking Fish At Home - Safely (PNW 238) explain the importance of preparation of fish prior to smoking, directions for smoking (and cooking phase) and storage of the finished product.
Smoked fish intended for canning is given a lighter smoke than fish meant to be consumed within 1-2 weeks. A lighter smoke leaves more moisture in each piece making it less dense. This allows heat to penetrate all portions of the fish during processing assuring the destruction of the bacteria Clostridium botulinum. These recommendations are given in Home Canning of Smoked Fish, PNW 238.
A certain strain of Clostridium botulinum is associated with marine waters and can be found on seafood, which can then be transferred into the canning jar prior to closure. After processing and the removal of air from the jar, C. botulinum if not destroyed in the heating phase is there to manufacture its deadly toxin.