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SMART PRODUCTI
SMART PRODUCTIONON

• Freezing: Of the many processing methods used to preserve fish, only freezing
can maintain the flavour and quality of fresh fish. Freezing greatly reduces or halts
the biochemical reactions in fish flesh. For instance, in the absence of free water,
enzymes cannot react to soften and degrade the flesh. The three steps for freezing
fish include immediate cooling and holding, rapid freezing, and cold storage. If fish
is frozen improperly, structural integrity may be compromised because of enzymatic
degradation, texture changes, and dehydration.
- Immediate Cooling: The rapid cooling and holding of fish at temperatures
between 2 and -2 °C (36 and 28 °F) takes place immediately after the fish have been
harvested.
- Rapid Freezing: The key to freezing is rapid reduction of the temperature to
between -2 and -7 °C (28 and 20 °F). This temperature range represents the zone
of maximum ice crystal formation in the cells of the flesh. If water in the cells freezes

• Heating: Heat treatment can significantly
alter the quality and nutritional value of fish. Fish
is exposed to heat during both the cooking
process and the canning process.
- Cooking: Fish is cooked in order to produce
changes in the texture and flavour of the product
and to kill pathogenic microorganisms. Heating
fish to an internal temperature above 66 °C or
150 °F is sufficient to kill the most resistant
microorganisms. The cooking time must be
closely regulated in order to prevent excessive
loss of nutrients by heat degradation, oxidation,
or leaching (the loss of water-soluble nutrients
into the cooking liquid).
- Canning: The canning process is a
sterilization technique that kills microorganisms
already present on the fish, prevents further
microbial contamination, and inactivates
degradative enzymes. In this process fish are
hermetically sealed in containers and then heated
to high temperatures for a given amount of time.
However, sterilization does not kill all
microorganisms, and bacterial growth and gas
production may occur if the products are stored
at very high temperatures.
Because the severe thermal conditions of
canning cause the disintegration and discoloration
of the flesh of many species of fish, only a few
types of fish are available as canned products.
The most common types are tuna, salmon,
herring, sardines, and shrimp. The thermal
processing does not have a detrimental effect on
the high-quality protein of the fish. In addition,
these species are often canned with their bones
left intact. The bones become soft and edible,
significantly increasing the level of calcium
present in the fish product. Tuna is an exception;
because of special handling considerations, the
bones of tuna are removed prior to canning. Tuna
is normally caught far offshore and must be frozen
and held for some period of time prior to canning.
During this freezing and holding period
unsaturated fatty acids are oxidized, causing the
tuna to become rancid. The rancidity is removed
by pre-cooking, and the bones are removed at
this time in order to facilitate the cutting and
preparation of the meat for canning.

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