Canning is one type of food safety process.

1. Canning of
commercially
important Finfishes

2. WEST BENGAL UNIVERSITY OF
ANIMAL AND FISHERY SCIENCES
FACULTY OF FISHERY SCIENCES
SUBMITTED TO SUBMITTED BY
Prof. K . C. Dora
Dept of FPT
Shrija Majumder
F/2021/30
SibaprasadMaity
F/2021/31

3. Introduction
The principles behind canning is that application of
sufficient amount of heat to food in an air tight
container in such a way that food is free from spoilage
as well as pathogenic microorganism. This technique is
given by Nicholas Appert, 1809.
The 3 essential maxims of canner as below,
 Container seal integrity
 Adequate thermal process lethality
 Scrupulous post-process hygiene

4. Shapes Involve in canning
01
03 04
 Selection and Preparation of Fish
 Salting/Blanching/Precooking
 Can filling
 Exhausting
 Can Coding
 Can Seaming, Double Seaming
 Can Washing
 Thermal Processing
 Cooling the container& contents,
drying, labelling & storing

5. 20
10
20
13
20
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 Fresh uncontaminated fish should be
used as the raw materialfor canning.
 Dressing needs depend on type of fish &
the type of end productdesired:
 Tuna – Bleeding.
 Small fishes (Sardine) - Beheading,
Gutting, Scaling & Removal of fin &
tails.
Selection and Preparation of Fish

6. 20
20
20
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7. It consists of keeping or immersing
the cut pieces of fishes insaturated salt
solution at required length of time.
 To give a salty taste.
 To make a texture of fish firmer i.e.,
to improve the texture.
 For appearance of the product. It
will clean the blood & slime.
 It also removes the problem of
curd formation in canned product.
It’s purposes-
Salting

8.  Causes sufficient shrinkage of fish to enable adequate filling in the
cans.
 Imparts firm & proper texture to the meat making its handling easy.
 Cleanses the fish meat, reduces bacterial load.
 Inhibits enzymatic action & maintains nutrition value by retarding
browning reactions.
 Sets the natural color & removes the raw flavor of fish.
 Expels the respiratory gases from the tissues thus helping
to improve vacuum in thecan.
 To reduce moisture content (15-30%) of fish (Hot Blanching).
Dressed fish is generally blanched in cold or hot brine or precooked in
steam.
Blanching
Main Functions:-

9. It generally consists of cooking of fish in steam
either after packing into the can or before packing
outside the can.
Precooking
 To improve quality of fish.
 To reduce moisture content (15-30%) of fish.
 To make the texture firmer.
 Helps to pack more quantity of fish.
 Also helps in reducing the curd & thus improving overall
appearance of theproduct.
 Inhibits enzymatic action.
 Expels the respiratory gases from the tissues.
 It’s purposes-

10.  The blanched material is filled in clean cans.
 Then it is covered with a liquid medium like hot brine, oil
orsauce.
 The cans are filled in such a way that a uniform
headspace(6-9mm) & ratio of solid to liquid should be
uniform.
 The can ends are clinched to the can body.
 Double refined deodorised vegetable oil is the principal filling
medium used in fish cans.
 Tomato sauce ( Solid percentage 30%) is an important additives in
canned sardine, mackerel etc.
Can Filling

12. A PICTURE IS WORTH
Filled Cannes

13. Exhausting
Exhausting is the process by which air from the
contents & headspace of a filled can is removed
before seaming the can.
Functions are as below,
 Minimized the strain on the cans & seam
due to expansion of air duringheat
processing.
 Removes oxygen which accelerates internal
corrosion of the can.
 Creates a vacuum when the can is cooled.

15. Can Coding
• It is a statutory requirement
to stamp the can ends with a
code denoting the contents,
date of manufacture & other
details as demanded under
food law.
• For identification of can
manufacture.
• After exhausting can should
be codded in figure & letters
using an embossing machine.

17.  Cans are seams immediately after
exhausting or along with exhausting.
 The objective of can seaming is to get
an air tight seal between cover and the
body.
 A good quality tinplate, adequate
sealing compound and an efficient can
closing machine combine to produce
a strong hermetic double seam.
 Sealed can are also subjected to
pressure testing for checking the
perfection of the seam.
Can Seaming

18. Cross Section of Seam

19. Double Seaming
It is an operation, in which the curl of
the lid and the flange of the canbody are
hooked, rolled and pressed by machine
in two successive operations, so that an
air tight joint is formed.

20. Can Washing
 Cans leaving the seaming machine may have pieces of
fish, sauce or oil adhering to the surface – may
contaminate the retort, clog it & becomes source of
contamination for next batch.
 Fish pieces sticking- when removed after
retorting_ peelinglacquer_ exposing potent
area for corrosion.
 Sealed cans are washed before retorting in
hot detergentsolution_ 1-1.5% sodium
phosphate @ 80˚C.
 Then rinsed in hot water to remove any
detergent residue(corrosion).

22. Heat Processing/ Retorting
 The sealed cans are heated for a predetermined
time-temperature schedule in saturated steam.
 Thermal processing should take care:
 Consumer safety.
 Ensuring non-spoilage under ordinary conditions of storage
anddistribution.
 Proper cooking of the product.
 Retention of organoleptic characteristics.
 Complete sterility is not the aim of heat processing _
may affect wholesomeness & render the product
organoleptic unacceptable.

23. Cont….
• Bacteria, spores forming and non spore former,
can be presentin canned foods and may not
spoiled the contents under the normal condition
of storage.
• The dormancy of the bacteria is
favoured by fat thatencapsulates &
renders them insensitive to heat.
• So as long as the product is free from
pathogens _ can beconsidered hygienically
acceptable.
• This has given rise to the concept of “commercial sterility”
A condition achieved in a canned food by
application of heat that renders the food free of
viable forms of micro-organisms having publichealth
significance as well as any micro-organism having no
public health significance capable of reproducing in
the food under the normal non-refrigerated
conditions of storage & distribution.

24. Factors of thermal processing
 The important consideration in canned fish is preventing the growthof
Clostridiumbotulinum,afood poisoning bacteriathatcan produce a highly
lethal toxin under anaerobic condition.
 Asterilization process whichensuresdestruction of Clostridiumbotulinum
spores will kill most of the organisms which can spoiled can fish under
the normal condition of handling and storage.
 Areductioninthe populationof Clostridiumbotulinumbyafactor of 1012 is
considered essential in canned fish.
 In order to kill Clostridium botulinum spores, the centre of low acid pack
must attain a temperature of 121˚C for a minimum of 2.52 minutes.
 This is the minimum “botulinum cook” necessary to reduce the
probability of spores survival to 1 in 1012 cans.

26. Cooling of Cans
After heat processing, cans are cooled immediately either
in air or more commonly in water to the ambient
temperature. Cooled cans are dried, labeled and stored.

27. Aftercooling anddrying,the labels should be put on the cans. The labels
should display all the informationsuch asname of the product, additives
added,net weightanddrainedweightof contents, dateof manufacture,
batchnumber, licence no, manufacturesaddressetc., All the principles
of labelling should be adheredto the adhesive,non corrosiveandnon
toxic andthe label should be in accordancewithfood laws andother
laws.
Labelling of cans

28. Thelabeled cans arestoredin cool anddry place. Thestorageshould be well
ventilated andtemperaturefluctuations should be minimum. There should not
be any corrosivefumes and gasesentering the storageroom. Normally cansare
storedincasesandcaseswithcansshould be kepton woodenplatforms. The
storedcansshould not be exposed to directsunlight.
Storage of cans

29. Canning of individual category to fish
 Salmon and Salmon like fishes:
There are several species of salmon are commercially
available and the species preferred is based on the
color of the meat and fat content. Some of the
commercially available varieties are as follows.
 King salmon/sock eye salmon/ red salmon: The meat of this fish
is firm with bright red color and it is medium fatty fish.
 Spring salmon: The color of meat is pink to deep pink, has medium
texture, oily flesh.
 Silver salmon: Meat color is pale, oily, firm flesh.
 Pink salmon: Meat color is pink but soft flesh.
 Chum salmon: Yellow flesh.

30. 1. For canning both fresh and frozen raw materials are used and they are
graded before dressing.
2. For dressing salmon, iron chink machines are used which removes head and
tail, splits the belly and removes viscera and fins.
3. After dressing it is transferred to trimming table for removing adhering loose
pieces of flesh, blood remnants and further subjected for water washing.
4. The fish are cut to size depending on the type of container used.
5. The packing of fish is done manually.
6. The filled cans are added with required quantity of powdered crystalline salt
to get good taste and then sealed.
7. This is the simplest procedure with minimum treatment given to raw material.
8. In this style of canning fish retains its original characteristics to a maximum
extent and hence it is called as natural style/pack or salmon style.
9. For this style very fresh fish is required. If very fresh mackerel is available, it
can be packed in natural/ salmon style.
Canning of Salmon

31. Specific problems encountered in salmon canning:
 Curd formation and adhesion.
 Abnormal petroleum odour due to dimethyl sulphide often encountered in
canned chum salmon. This is due to the consumption of “Pteropoda”
(Limacina helicina) plankton. The plankton contains a chemical compound
dimethyl, β propiothetin which is absorbed by the flesh of the fish and gets
converted to dimethyl sulphide during heat processing.

32.  Tuna and tuna like fish
Several varieties of tuna are being canned. Some of the
important varieties are:
 Albacore/long fintuna
 Yellow fin tuna
 Bigeye tuna
 Blue fin
 Skip jack
 Bonito

33. Canning of tuna
For tuna canning, both fresh and frozen material are used. There are
several styles of canned tuna products. The different steps involved in
canning of tuna is by and large same despite differences in variation in the
size of the species, proportion of light and dark meat and the styles of liquid
fillings.
After dressing the fish are semi dressed and precooked. Precooking is done
at 100 to 105oC and time may vary from 1-7 hr depending on the size of fish.
During precooking the centre temperature should attain at least 71oC. After
precooking, it is cooled and partially dried in chilled atmosphere. Separation
of light and dark meat is achieved manually and light meat is used as lions for
packing into the cans.

34. Processing
flowchart
of Canned
Tuna

35. Various styles of packing of tuna meat in
cans
 Solid pack consist of cleaned loins cut in transverse segment suitable for
packing in one layer based on can size without placing any transverse
segment parallel to can ends.
 Chunk style consists of mixture of pieces of tuna in which 50% is the
pressed loins and the rest may be smaller pieces of ½” size or smaller.
 Grated style: Tuna meat is reduced in size using a grinder to uniform
size of less than ½”. The particle must be discrete and should not
become a paste.
 Flakes – small meat chunks which are obtained during grating of tuna
meat.

36. Changes taking place by
precooking and cooling
 Loss in its weight to the extent of 25%.
 Physico-chemical properties of muscle change
 Coagulation of meat proteins
 Firmness in meat due to partial dehydration
 Improvement in nutritional value
 Improvement in taste and appearance.

38.  Canning of Sardine
Mediterraneanmethod: Fish is washed in brine first and then
Nobbed (Nobbing refers to removal of head, gills and entrails).
Nobbing is achieved mechanically. Alternatively, nobbed fish is
then brined. The nobbed fish packed into cans, precooked at
100oC normal atmospheric pressure using steam.The period
precooking varies from 15-30 min depending on the size and fat
content of fish. After precooking, the cans are inverted to drain
liquor comprising water and fat. The precooked fish is filled with
brine / oil prior to seaming.
Norwegianmethod: In this method Nobbing and brining
procedure is similar to Mediterranean method. Then it is hot
smoked and dried (smoking at 80oC for 2 hr) and then packed
into cans. The filling media can be either brine or vegetable oil
and then subjected for seaming and heat processing.

39. Conclusion
The seafood canning had its origin in North America
and later spread to Europe, Japan and other
countries. The technology for the container
development (tin cans) was the key to successful
canning of seafood. The canning of salmon, mackerel,
sardines and mackerel like fishes, tuna are produced
commercially.
Canned fish are rich in protein and many other
essential nutrients and can be a good source of
omega-3 fatty acids.

41. THANK YOU