6 Ways To Preserve Fish

6 ways to preserve fish

By Dr Anny Manrich (PhD)

Page last updated: 02/04/2023 | Next review date: 02/04/2025

Author bio

Dr Anny March PhD is a food Engineer with expertise in Food Technology, Natural Polymers, Edible Films, Enzymes, and Nanotechnology.

Dr Anny Manrich’s Highlights:

Research and Technology at the Brazilian Agricultural Research Corporation
Dr Anny Manrich (PhD)

View More north_east

In this brief guide, we are going to answer the question “6 ways to preserve fish” and discuss 6 ways to preserve fish along with the benefits and implications of each method.

The U.S. now imports more than 80% of its seafood, mainly from China, Thailand, Canada, Indonesia, Vietnam, and Ecuador (1).

6 common ways to preserve fish are:

Freezing
Vacuum packing and freezing
Smoking
Canning
Brining
Drying

Preserving fish by freezing

Freezing is the most commonly used method to preserve fish. Frozen fish has the best quality and tastes closest to freshly caught fish.

Freezing acts as a preservative by reducing the temperature at which chemical reactions take place and by lowering water activity (aw), which inhibits microbial growth. Freezing is the most popular means of preservation, at 53% of all fish processed for direct human consumption (2).

Fish must always be cleaned and gutted before freezing. Bigger fish are also portioned into a size needed for cooking later one while smaller fish can be frozen whole.

For bulk storage, fish can be placed in a clean container which is topped off with water. The whole container can then be frozen.

It is important to maintain the freezing temperature between – 18 °C to – 22 °C at all times.

The shelf-life of frozen fish depends on the variety of fish. For example fish with a high-fat content such as tuna and salmon have the lowest frozen shelf-life of about 3 months while lean fish would last for about 6 months.

Vacuum packing the fish before freezing will significantly increase its shelf-life. We will discuss vacuum packing next.

Preserving fish by vacuum packing and freezing

Vacuum packing and then freezing is one of the best methods to preserve fish.. The only disadvantage of vacuum packaging is that it requires special equipment.

Vacuum packing works by removing the air around the fish and then sealing it in a vacuum. Once the air is removed there will be a depletion of oxygen for the aerobic microbes that cause spoilage. Reduced oxygen content also lowers the risk of spoilage due to oxidation.

Vacuum packaging, along with cold temperature, have been found as enhanced preservation techniques and could provide improved seafood shelf life and suitable organoleptic quality. However, packaging without oxygen may result in fat oxidative spoilage as well as improved organoleptic properties in fish. The packaging process in the absence of oxygen and in cold storage is a way to prolong the shelf life, thus the oxygen can lead to microorganisms and photolytic activities in packed fish fillet without vacuum (3).

Vacuum packing can be done on any variety of fish. Some fish varieties that preserve well by vacuum packing include salmon, swordfish, halibut, tuna and trout.

Once again, it is important to maintain the freezing temperature between – 18 °C to – 22 °C at all times.

Preserving fish by smoking

Smoking is an efficient and flavourful method of preserving fish. During smoking, fish is directly cooked from the smoke of wood. The wood smoke along with low temperature, and long cooking time imparts a distinct flavor to the fish.

The preservative effect is derived from reduced water activity (enhanced by salting) and the physical barrier represented by the dried fish surface combined with the antimicrobial and antioxidant properties of the phenolic compounds released in the wood smoke (2).

Smoking works by creating an acidic coating on the surface of the fish, which kills bacteria thereby slowing down decomposition and spoilage. Smoking is more effective when the fish has been soaked in brine. Smoking and then vacuum packing preserves fish for about 3 weeks. Smoked, vacuum-packed fish can be frozen for about 3 months.

Fish is sometimes cured with salt before smoking. This prolongs the shelf-life of smoked fish.

Preserving fish by canning

Canning is a high energy thermal process as applied to foods can be divided into three levels of severity depending on the pH of the food. Thermal sterilization is a heat treatment process that completely destroys all the viable microorganisms (yeasts, molds, vegetative bacteria, and spore formers) resulting in a longer period of shelf life (4). Low acid (above pH 5.3) products (including most canned fish products which are canned at about neutral pH) require a full heat treatment and rapid cooling to prevent the germination of surviving spores (2).

Canning is a time consuming and technical yet effective way of preserving fish for long term use. Commercially canned fish has a shelf-life of 2 to 5 years.

Canning fish must always be done using a pressure canner. Salmon, mackerel, trout and tuna are some varieties of fish that are usually canned.

A guide to canning fish at home can be found here.

Preserving fish by brining

Brining is done by immersing fish in a salt solution. The salt will draw out the moisture from the fish, thereby preventing the growth of microbes. Salt will also directly destroy some microbes. Salt can be applied directly to the fish (‘dry’ salting), and the brine formed by extraction of water from the fish (due to osmotic pressure) is allowed to drain off. In the ‘wet’ process the fish is immersed in a brine (pickle) solution (2).

A disadvantage of brining is the high salt content used which has been associated with hypertension. The Dietary Guidelines for Americans, 2020-2025 recommends limiting sodium intake to 2,300 mg per day for people 14 years and older; and even less for those 13 years and younger (4).

There are several different recipes for brining fish. A recipe for brining fish can be found here.

Preserving fish by drying

Drying is a traditional method that has been used to preserve fish for ages. Fish is usually salted before drying. Fish can be either air-dried, sun-dried or even dried with a dehydrator. Drying removes the moisture from fish which in turn prevents the growth of microbes. Fish with a low-fat content such as cod, sardine, pollock, mackerel and tuna preserve longer with drying.

After drying, the fish must be stored in an airtight container or a vacuum-sealed bag to prolong the preservation time. Fish drying can take the form of air- or contact drying where heated air extracts and removes moisture, drying under vacuum at reduced temperature and freeze-drying, where moisture is removed by sublimation from frozen material under vacuum (2).

Dried fish will preserve well for years. Disadvantages of drying fish include the high salt content may make it unsuitable for people with hypertension and the permanent change in texture and flavor of fish.

A detailed method for drying fish can be found here.

Other FAQs about Fish that you may be interested in.

Why do you eat 7 fish on Christmas eve?

Can you eat Jack Crevalle?

Can you eat Oscar fish?

Conclusion

In this brief guide, we answered the question “6 ways to preserve fish”. We discussed 6 methods of fish preservation and looked at the benefits and implications of each method.

If you have any questions or comments, please let us know.