Course:FNH200/2012w Team20 Salmon

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Introduction

In the past, the abundance of salmon in British Columbia has allowed this fish to be a staple in the Aboriginal diet. Aboriginals have long utilized various methods for preserving salmon from salting to smoking. In British Columbia alone, there are five species of salmon. Salmon are preserved to increase shelf life and/or to give the fish flavours. They can be prepared in many ways, and can be enjoyed in sweet or savoury dishes. [1]

History

There is a long history of salmon preservation and processing in British Columbia. There is archaeological evidence that dates back 8,000 years, where fish drying rocks have been recovered from the Fraser River. Aboriginal people have also used salt preservation dating back centuries, as have many other cultures in the world. Processing of salmon on the West Coast began in the late 19th century with the advent of new discoveries and techniques. [1]

Types of Salmon

Salmon is the common name for Salmonidae which is the name of the nine commercially important species in this fish family. Most of the world's salmon live in the North Atlantic and Pacific Oceans. Atlantic salmon types are Atlantic, Chinook, Chum, and Coho salmon. Pacific salmon have the common names of Coho, Pink, Sockeye, Steelhead, and Masu salmon. [1]

  • Masu salmon are only found in Japan, Korea, and Russia in the Western Pacific Ocean.
  • Chinook salmon are the largest of all Pacific salmon and are found in the northern parts of the Pacific Ocean.
  • Chum salmon are found in the Pacific along the California coast to the Sea of Japan and the Mackenzie River in Eastern Canada and Siberia in the West.
  • Coho salmon are native to the waters of Alaska and British Columbia and live as far South as Central California.
  • Pink salmon, the smallest of the Pacific species, are found in the Pacific Ocean near Northern California and off the coast of Korea to Siberia.
  • Sockeye salmon are found in the waters of the Eastern Pacific in California and live as far North as the Canadian Arctic and Siberia. In the Western Pacific, they are found in Japan. [1]
Nomenclature of wild salmon given by Agriculture and Agri-Food Canada
Wild Salmon

There are five species of wild salmon in British Columbia. They are Chinook, Chum, Coho, Sockeye and Pink. [2]

Farmed Salmon

In Canada, the predominate species farmed is Atlantic salmon (Salmo salar). There are two species of farmed Pacific salmon, which are Chinook (Oncorhynchus tshawytcha) and Coho (Oncorhynchus kisutch). [3]

Grades of Salmon

According to Agriculture Canada, there are three grades of salmon: Grade 1, Grade 2, and Commercial Grade. All grades are evaluated based on external appearance, internal appearance, and flesh texture and odours. Four factors that contribute to this evaluation include condition of the fish when caught, handling, storage conditions, and sexual maturity.[2]


  • Grade 1-quality fish have no defects in the edible portion of the fish. The skin colour is required to be typical of the species while the skin itself must not display any reddening. Internally, the fish must be free from belly burns, viscera and blood, and visible bruises. Lastly, the fish must have resilient flesh and not retain any abnormal odours. [2]
  • Grade 2-quality fish are allowed to have some leniency in defects. For example, externally, they are allowed to display some clean cuts, moderate reddening, and moderate to heavy scale loss. Internally, the belly burn may be very evident, but the gut cavity must still be free from all viscera and blood. In terms of flesh texture and odour, flesh is expected to have lost the majority of its resilience. Similar to Grade 1-quality fish, the fish must not retain any abnormal odours. [2]
  • Commercial-Grade quality fish will be fish that fall under Grade 2-quality fish, but still qualify for human consumption. Externally, the fish may have clean cuts or breaks in skin from any source. Qualities that define Commercial-Grade fish include extreme reddening of the belly, heavy to extreme scale loss, and net marks that have indented or punctured flesh. Internally, the fish may have visible bruises along with clean cuts or tears in skin and belly cavity. However, like Grade 1 and Grade 2-quality fish, Commercial Grade fish are required to be free from viscera and blood in the gut cavity and also fairly free from residual blood water. Finally, rather than minimal skin resilience, Commercial Grade fish may emerge as very soft-like with flesh separation very evident in belly cavity. [2]

Types of Salmon Processing

Salted Salmon

Salted salmon

There are many methods of preserving (curing) salmon, one of which has been around for a significant amount of time involving the use of large amounts of salt. This method dates back many centuries ago and has been applied by numerous cultures. [4]

The Hudson’s Bay Company introduced the ancient art of fish salting to the West Coast around 1830 when they began mild-curing salmon in large brine-filled barrels in Fort Langley. The salted fish was mainly for shipping overseas.[1] Presently, salting fish is used commonly as an inexpensive household form of preservation of salmon. Sometimes, an assortment of herbs is used in addition to large amounts of salt and rubbed onto the surface of the salmon. The reason why salt is used is because it has the ability to bind to substantial amounts of water, so when salt is rubbed onto salmon, the amount of free water is decreased significantly in the salmon. This results in less water that is readily available for use by microorganisms, thus controlling and preventing their growth and preserving the food system. Less water activity also substantially decreases the rate of chemical and enzymatic reactions that otherwise happen naturally in salmon. Thus, dehydration of salmon by using salt prevents spoilage and extends its storage life. [4]

How to cure salmon using salt:

  1. First, rinse off the salmon using cool water and pat it dry with a paper towel.
  2. Mix salt, sugar, and liquid (of your choice depending on your desired flavor of salmon, for example, lemon or lime juice) to create a thick rub. Rub the salt cure all over the surface of the salmon by pressing it down and evenly over the fish.
  3. Wrap the fillet in plastic wrap as tightly as you can and place onto a baking dish (skin side down if there is skin). Place a flat dish on top of the fish and place a heavy object on top to place pressure on it.
  4. Refrigerate for 24-48 hours and drain any liquid that has been drawn out from the salmon onto the dish during the refrigeration process. If curing a fillet without skin, then flip it over halfway through the curing process so that each side can be weighed down for an equal amount of time.
  5. After refrigeration, unwrap the fish and rinse off the rub with cold water then pat it dry. [5]

Dried Salmon

Dried salmon

Drying has been used for thousands of years and was likely the first method used to preserve fish. Historically, it gave the Aboriginal people the ability to store the abundant Pacific salmon runs so that they would have a year round food source. To this day, the Aboriginal people still dry their fish.[1]

How to dry salmon in the household:

  1. Firstly, remove all the ribs and bones from the salmon and wash the slime and scales off of it.
  2. Dry the salmon with a paper towel.
  3. After seasoning the fillet with your desired spices of choice, make cuts in the flesh at a 45 degree angle across the fillet. Ensure the skin is not cut through.
  4. Hang the salmon on a rack and store in a cool environment with a fan blowing on the fish. Allow the fish to dry for 5-7 days until it acquires a ‘jerky’ texture.
  5. At this point, the fish can be cut into pieces, bagged, and frozen. [6]

Smoked Salmon

Smoked salmon

Smoking is an ancient technique that is used to preserve and add colour to fish. Smoked salmon is a specialty product in many countries and its small-fish industry has thrived in British Columbia for many years.[1] It is available in cold-smoked and hot-smoked forms. [7]

Cold smoking salmon is a long process. Before the salmon is smoked, it is cured in a salt brine solution of sugar, salt, pepper and spices for two to five days. This process preserves the fish and prevents the growth of microorganisms by lowering the water activity. The brine is also used to enhance and add flavour to the fish. The cured salmon is then drained, rinsed and refrigerated for about 12 hours. After refrigeration, the cured salmon is smoked over a wood fire for about 12 hours at cool temperatures ranging from 21°C to 32°C. The salmon isn’t necessarily cooked, and thus has a shorter refrigerator life compared to hot-smoked salmon. Cold smoking maintains the salmon’s rich colour while slightly firming the flesh, but still providing a silky and appealing texture. The smoky taste depends on the length of smoking and the type of wood use. Cold-smoked salmon is primarily used in cold dishes such as sushi and sandwiches, but can also be paired with cooked dishes such as pasta. [7]

The process of hot smoking is very similar to that of cold smoking, but the timing and temperatures are different. The salmon is cured in a salt brine solution for three days, and then smoked at higher temperatures ranging from 49°C to 82°C for up to 12 hours. The higher temperatures allow the salmon to become fully cooked and have a longer shelf and refrigerator life. As with all smoking processes, the size of the fish and the amount of smoky flavour desired will influence the smoking time and temperature. Hot-smoked salmon can be eaten on its own as a snack, or it can be added to a variety of cooked and uncooked dishes such as pasta, soups and salads. It has a drier, flakier texture and smokier flavour compared to cold-smoked salmon. Hot-smoked salmon is also used as the base for smoked salmon pate. [7] [8]

Candied Salmon

Candied salmon originated on the West Coast of North America. Thin strips, chunks or nuggets of salmon are soaked in a salt-sugar brine and are then hot-smoked at temperatures between 48.9°C to 82.2°C to fully cook the fish. During smoking, the fish is blasted with sweeteners, such as honey, maple syrup, brown sugar syrup or a combination of sweeteners. Some producers separate the smoking and sweetening steps, so the salmon is first partially smoked and then soaked in a sweetener for several hours before completing the smoking process. [9]

Candied salmon is a perishable product that must be refrigerated. Once it is opened from its packaging, it can only be kept in the fridge for up to three days. Candied salmon can be enjoyed as a snack or appetizer, but it can also be used in a variety of cooked and uncooked dishes such as pasta, salad, chowder and quiche. [9]

Frozen Salmon

Frozen salmon

Fish were first frozen artificially in 1861 but it became more large-scaled in the late 19th century with the advent of mechanical refrigeration. In the mid-1930’s the flash freezer was introduced and this process made freezing faster and gave better results.[1]

Freezing is a practice widely used to preserve seafood products. The purpose of doing so is that low temperatures of food storage decrease the rate of enzymatic, chemical, and microbial reactions in food that prolongs storage life. The emphasis should be placed on the fact that freezing only decreases the rate, as a common misconception amongst households is that the content of the frozen food will not be altered during storage at refrigeration. In short, how the food is prepared before frozen storage is crucial to its quality when the food is thawed.[1]

Freezing salmon can be split into two categories: home freezing and commercial freezing. For household freezing, the salmon must be wrapped to ensure that the two most common defects do not occur: the oxidation of tissue lipids that causes unnatural flavors and freezer burns that can be attributed to moisture loss. There are several ways of packaging, including vacuum packaging, plastic wraps, aluminum foil, freezer bags, freezer paper, and waxed paper cartons. The most effective method of packaging is vacuum packaging as it guards best against oxidation and desiccation due to its tight and sealed packaging that completely nullifies air. After wrapping is complete, it is best to freeze the salmon at once since the household freezer can reach temperatures of -12 to -14°C- the temperature (-9.5°C) that microorganisms thrive in. [10] [11]

For commercial freezing, fish are immediately placed in freezers at a temperature below -18°C after being caught to retain freshness. Once fish are frozen and removed from freezers, they undergo either glazing or wrapping (unless they have been packaged before freezing). Glazing is the most widely used approach to protect frozen fish products from dehydration, oxidation and other unwanted changes during cold storage. It is initiated by dipping the frozen product in or spraying the frozen product with potable water. By doing so, a protective coating of ice will form; this process is repeated until the product is fully sheltered in this coating of ice. This technique is very effective against dehydration and freezer burn since glazing isolates the surface of the product from oxygen, reducing the rate of oxidation. However, the drawback includes a higher chance of desiccation since the glaze is so fragile that it can be easily cracked. [12] [13]

Sashimi

Sashimi is food that consists of fillets of marine fish, molluscs, crustaceans, fish roe, or other seafood meant to be consumed in its raw state. The quality of the salmon is directly proportional to how safe it is for raw consumption; therefore, the better the safer. Given that sashimi is a cuisine that does not undergo any cooking processes to eradicate food poisoning bacteria or parasites, there must be a very high standard of hygienic production. According to the FDA, to remove any roundworm or tapeworm larvae, sashimi must initially be frozen at a temperature of at least -20°C for 24 hours. For consumption, sashimi must be thawed in a chiller and then stored at or below 4°C. At this stage, the sashimi can be consumed after being washed and cut into its desired shape. [14] [15] [16]

Canned Salmon

Canned salmon at the Gulf of Georgia Cannery
Canned salmon 2

In 1809, a breakthrough discovery was made when it was discovered that if food was heated long enough and sealed tightly, it would keep for long periods of time. From his invention came the process of canning salmon in 1871 in British Columbia. It allowed for the preservation of the rich salmon resources and shipments to Europe. [1]

The low acidity of fish allows spoilage-causing microorganisms to thrive. In order to kill and prevent the growth of microorganisms in canned salmon products, the canned salmon must be sterilized under high temperatures ranging from 116°C to 130°C. Pressurized cooking methods can achieve these high boiling points. Canning prevents microorganisms from entering the processed salmon as it is sealed in an airtight container. [17]

According to UBC’s report entitled Nutritional Analysis of British Columbia Canned Salmon by the Department of Food Science, it was reaffirmed that BC canned salmon is a good source of nutrition which provides well balanced and easily digestible protein, polyunsaturated fatty acids, omega-3 fatty acids, calcium, potassium, vitamin D, B vitamins, and phosphorus. Omega-3 fatty acids has been associated with positive cardiovascular health and decreased risk of atherosclerosis (clotting of blood vessels by plaque build-up on vessel walls). Much calcium is found in canned salmon due to the edible soft bones (canning softens the bones); calcium contributes to lowered risk of osteoporosis (deterioration of bone with age). A typical 3oz can of canned salmon contains about 200 mg of calcium, which is equivalent to a glass of milk. [18]

A typical production process for canned salmon involves heat processing of the cans of salmon in steam pressure vessels at a minimum temperature of 225 degrees Fahrenheit (about 107.2 degrees Celsius) for a minimum of 18 minutes. After this initial step, the cans are further heat processed to kill disease-causing microorganisms. The cans are cooled to only about 140 degrees Fahrenheit so that sufficient heat remains, preventing the cans from rusting while allowing them to dry. Lastly, the canned salmon is inspected (quality control step), screened (according to criteria set out by the CFIA Screening Protocol to ensure good manufacturing practice standards), labelled, and inspected a final time before shipment. [19]

Other Salmon-based Products

Salmon oil

One product derived from salmon is salmon oil, which is beneficial because it is rich in Omega-3 Fatty Acids. Claims are made that it helps to reduce high blood pressure and is helpful to those suffering from rheumatoid arthritis, relieving joint pain and swelling. It is said to also help in healthy brain and nerve cell function. [20]

Some other by products of salmon include fresh salmon eggs, aquatic plant food, and pink salmon pate which has a smoked taste and is used for canapes. Salmon eggs are used as a substitute for caviar but are quite different than caviar in how they appear, taste, and where they originate. On the international level, salmon by products such as Salmo salar or Atlantic salmon and Oncorhynchus spp or Pacific salmon are exported from countries such as Germany. They are exported as by products in the form of Salmon belly flaps, Salmon tails, cold-smoked Salmon slices and trimmings. [21]

Research is now being done on processing of farmed salmon waste which is rich in marine oils and proteins to replenish the diminishing supply of these important ingredients for conversion into useful products such as salmon hydrolysate and oil. [22]

Preparing Salmon at Home

Sharon’s mother was perhaps one of the ‘original’ full-time working mothers. It was unusual in the 1950’s for a woman to work and have a family. She would prepare a salmon loaf for each and every Saturday for the family to cook on Saturdays while she was at work. It was not only a nutritious meal but an easy meal to prepare beforehand and also relatively inexpensive. As a registered nurse she was very aware of good nutrition and she felt that the salmon loaf was a healthy meal as it was so rich in protein for her growing daughters.


Original Salmon Loaf Recipe
1 tin canned salmon
6 crushed saltine crackers
½ onion chopped
¾ cup milk
1 egg beaten
salt and pepper


Directions
1. Preheat oven to 350 degrees F.
2. In a mixing bowl, combine the salmon, cracker crumbs, milk, egg, salt, pepper, and melted butter. Mix thoroughly.
3. Press the salmon mixture into a lightly greased 9 x 5 loaf pan.
4. Bake in a preheated over for 45 minutes or until done.

Video

Salmon Processing

Conclusion

Some people may prefer salmon made with certain processing methods over others due to personal preference for taste, flavour, texture, and the degree to which the salmon has been processed. In British Columbia, we are lucky to have access to fresh salmon, which are available locally at places such as Fisherman’s Wharf in Richmond, BC. Some people prefer to cook freshly caught salmon at home because they prefer the fish without commercial processing, whereas others prefer canned salmon because of its convenience of little or no at-home preparation and cooking needed. Regardless of which type of processed salmon you eat, you will still receive the same nutritional benefits and delicious taste that salmon features!

Final Exam Question

What kind of processed salmon would you choose to eat? What methods does it take to turn a piece of fresh salmon into the delicious kind of processed salmon you would choose? Choose from the following:

1. Smoked salmon
2. Candied salmon
3. Sashimi
4. Canned salmon


Answers:

1. Smoked salmon (cold or hot)
Cold smoked:

  • Cured in salt brine of sugar, salt, pepper and spices (2-5 days); lowers water activity to prevent growth of microorganisms
  • Drained and rinsed, then refrigerated for 12 hours
  • Smoked over wood fire for 12 hours at cool temperature
  • Not to the point that it is cooked (lower refrigerator life than hot smoked)

Hot smoked:

  • Cured in salt brine of sugar, salt, pepper and spices (3 days); lowers water activity to prevent growth of microorganisms
  • Smoked at high temperature for up to 12 hours
  • Fully cooked (longer refrigerator life)

2. Candied salmon

  • Strips, chunks or nuggets soaked in salt-sugar brine
  • Hot smoked to cook fish
  • During smoking, blasted with sweeteners (honey, maple syrup, brown sugar syrup or a combination)

3. Sashimi

  • Vacuum packaging to protect against oxidation and desiccation; or glazing to protect from dehydration, oxidation and other unwanted changes during cold storage (dipping in or spraying the frozen product with potable water)
  • Frozen to decrease the rate of enzymatic, chemical, and microbial reactions in food that prolongs storage life (-20°C for 24 hours)
  • Thawed in a chiller and then stored at or below 4°C
  • Washed and cut before consumption

4. Canned salmon

  • Salmon sterilized under high temperatures to kill microorganisms
  • Cans are furthered heat processed to kill disease-causing microorganisms
  • Canning prevents microorganisms from entering

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Information was obtained from Steveston Harbour and Gulf of Georgia Cannery National Historic Site from touring the site and from the signs posted within the cannery.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Wild Pacific Salmon Overview. (2002, October 10). Agriculture and Agri-Food Canada. Retrieved March 14, 2013, from http://www.ats-sea.agr.gc.ca/sea-mer/4804-eng.htm
  3. ↑ Salmon. (2012). Canadian Aquaculture Industry Alliance. Retrieved March 16, 2013, from http://www.aquaculture.ca/files/species-salmon.php
  4. ↑ 4.0 4.1 Cured Salmon. (2013, March 11). Wikipedia. Retrieved March 20, 2013, from http://en.wikipedia.org/wiki/Cured_salmon
  5. ↑ How to Cure Salmon. (n.d.). wikiHow. Retrieved March 21, 2013, from http://www.wikihow.com/Cure-Salmon
  6. ↑ Qutekcak Native Tribe, Seward’s Native Pride. (n.d.). Qutekcak Native Tribe. Retrieved March 19, 2013, from http://sewardaknatives.com//
  7. ↑ 7.0 7.1 7.2 Types of Smoked Salmon. (2013). Thrifty Foods. Retrieved March 17, 2013, from http://www.thriftyfoods.com/EN/main/cook/tips-tricks/cooking-tips/seafood/types-of-smoked-salmon-20030820.html
  8. ↑ Smoking Techniques. (2013). Gourmet Food Store. Retrieved March 20, 2013, from http://www.gourmetfoodstore.com/smokedsalmon/smokingtech-smoked-salmon.asp
  9. ↑ 9.0 9.1 What is Candied Salmon?. (2013). Thrifty Foods. Retrieved March 20, 2013, from http://www.thriftyfoods.com/EN/main/cook/tips-tricks/cooking-tips/seafood/what-is-candied-salmon-20060726.html
  10. ↑ Home Freezing of Fish. (1986). University of Alaska Fairbanks. Retrieved March 19, 2013, from http://www.uaf.edu/files/ces/publications-db/catalog/hec/FNH-00222.pdf
  11. ↑ Landforce, A. S. (1972, February). Cutting and Freezing Salmon and Steelhead at Home. Oregon State University. Retrieved March 19, 2013, from http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/18244/183CuttingFish.pdf?sequence=1
  12. ↑ Treatment of Fish After Freezing. (2012). Food and Agriculture Organization. Retrieved March 17, 2013, from http://www.fao.org/docrep/003/v3630e/V3630E07.
  13. ↑ Glazing. (2008, May). Seafish. Retrieved March 19, 2013, from http://www.seafish.org/media/Publications/FS2-05_08-Glazing.pdf
  14. ↑ Safe Production of Sushi, Sashimi and Other Raw Fish Products. (n.d.). Cardiff Caerdydd. Retrieved March 22, 2013, from http://www.google.com/url?q=http%3A%2F%2Fwww.cardiff.gov.uk%2FObjView.asp%3FObject_ID%3D5910&sa=D&sntz=1&usg=AFQjCNE_Sbwm2Pc22n1Z-a24IJ8Ynh147w
  15. ↑ Fish and Fishery Products Hazards and Controls Guidance. (2011, April). Food and Drug Administration. Retrieved March 22, 2013, from http://www.fda.gov/downloads/food/guidancecomplianceregulatoryinformation/guidancedocuments/seafood/ucm251970.pdf
  16. ↑ Sushi & Sashimi in Hong Kong. (2004, April). Food and Environmental Hygiene Department. Retrieved March 23, 2013, from http://www.cfs.gov.hk/english/programme/programme_haccp/files/ss_ras2_eng.pdf
  17. ↑ Canned Salmon. (2013, February 5). Asia Grains Syndicate. Retrieved March 23, 2013, from http://www.parboiledricethailand.com/product/Canned+Salmon/Canned+Salmon+Parboiled+Rice+Thailand+36532.html#.UVKF8RxJOAi
  18. ↑ Vanderstoep J., Weintraub S., and Barber K. (1990), "Nutritional Composition of B.C. Canned Salmon", Canadian Institute of Food Science Technology Journal, Vol. 23, No.2/3, pages 121-124.
  19. ↑ Processing Wild Salmon. (2012). Gold Seal. Retrieved March 24, 2013, from http://www.goldseal.ca/wildsalmon/processing.asp
  20. ↑ Wild Salmon and Fish Oils Omega-3 Complex. (n.d.). Jamieson Natural Sources. Retrieved March 20, 2013, from http://www.jamiesonvitamins.com/2183
  21. ↑ Salmon by-products. (n.d.). Seafood-Express OCEANCOOL. Retrieved March 24, 2013, from http://www.oceancool.seafood-express.de/16.html
  22. ↑ Salmon Byproducts. (2004). Aqua Feeds: Formulation & Beyond. Retrieved March 22, 2013, from http://www.feedware.com/aqua/magazine/v1i1/salmonby.html


Additional References:

  • Photographs were obtained at Steveston Harbour and Gulf of Georgia Cannery National Historic Site with the permission of the cannery. Information was also obtained from touring the site and from the signs posted within the cannery, although there were no pamphlets or other resources available.
  • The video was filmed at Finest at Sea (Vancouver - Granville Island location) with the permission of the plant manager.
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