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DGYS/XXX/2016
2016-07-13
DRAFT GUYANA STANDARD
Specification for
Salted Fish and Dried Salted Fish
Guyana National Bureau of Standards
DGYS/XXX/2016
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This document is a Draft Guyana Standard. It is distributed for review and
comment. It is subject to change without notice and may not be referred to as
National Standard. Recipients of this draft are invited to submit, with their
comments, notification of any relevant patent rights of which they are aware
and provide supporting documentation.
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reproduced or utilized otherwise in any form or by any means, electronic or
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without prior written permission. Permission can be requested from the GNBS at the
address below.
Guyana National Bureau of Standards (GNBS)
Flat 15, Sophia Exhibition Complex,
Sophia
Georgetown, Guyana.
Telephone: 592-219-0064 – 66
Fax: 592-219-0070
Email: [email protected]
Website: www.gnbsgy.org
DGYS/XXX/2016
Contents
Page
Foreword
Standard
1.
Scope
1
2.
Definition
1
3.
Description
2
4.
Essential Composition and Quality Factors
8
5.
Food Additives
10
6.
Packaging Materials
10
7.
Hygiene and Handling
11
8.
Labelling
11
9.
Sampling, Examination and Analysis
12
10.
Definition of Defectives
14
11.
Lot Acceptance
15
12.
Appendix A- List of species of Fish used for Salting
16
13.
Appendix B- Sensory and Physical Examination for Fish for Processing
17
14.
Appendix C- Sample Method of Fish
18
15.
Appendix D- Determination of Water Content in Whole Fish by Cross
section Method
19
16.
Appendix E- Determination of Salt Content
23
17.
Appendix F- Moisture in Fish (Air Drying)
25
18.
Appendix G- Determination of Acid Insoluble Ash
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DGYS/XXX/2016
Foreword
This Draft Guyana Standard was adapted by the Guyana National Bureau of Standards
through its Technical Committee- Foods. It stipulates the requirements for Salted Fish
and Dried Salted Fish produced for retail and distribution for human consumption.
In the formulation of this standard, assistance was derived from the following publications:
1. UGANDA STANDARD, US 920:2012, Specification for Dried and Dry-salted Fish
2. CAC/GL 50:2004, Guideline for sampling
3. CAC/RCP 52-2003, Code of Practice for Fish and Fishery Products
4. Practical Methods for Preserving Seafoods, Salting and Drying, South Pacific
Commission, 1997
5. Report of the 6th Session of the Codex Alimentarius Commission, 1993
6. CODEX STAN 167: 1989, Standard for Salted Fish and Dried Salted Fish of the Gadidae
Family of Fishes
DGYS/XXX/2016
Members of the Technical Committee- Foods
Name
Affiliation
Ms. Jewel Sears (Chairperson)
Ministry of Public Health, GA-FDD
Ms. Seraiah Validum
Ministry of Public Health, GA-FDD
Ms. Grace Parris
Guyana School of Agriculture
Mr. Gary Mendonca
University of Guyana, Faculty of
Natural Sciences
Dr. Colin James
Ministry of Public Health, VPHU
Dr. Christina Brijmohan
Ministry of Public Health, VPHU
Mr. Randy Bumbury
Ministry of Agriculture, Fisheries
Dept.
Mr. Martin Poon
New Guyana Marketing
Corporation
Ms. Andrea Mendonca (Technical Secretary)
Guyana National Bureau of
Standards
DGYS/XXX/2016
Specification
for
salted fish and dried salted fish
1
Scope
This standard applies to salted fish and dried salted fish which has been fully
saturated with salt (heavy salted) or to salted fish which has been preserved by
partial saturation to a salt content not less than 12% by weight of the salted fish
which may be offered for consumption without further industrial processing.
2
Definitions
For the purpose of this standard, the following definitions shall apply:
2.1
acceptable quality level (AQL): acceptable quality level for a given sample is the
rate of non-confirming items at which a lot will be rejected with a low probability,
usually 5%.
2.2
acceptable quality: a basic level of quality that is expected for both salted and dried
salted fish.
2.3
dun: a discolouration and a development of the mould Sporendonema epizoum
which affect the fish surface and make it look like peppered. The fish flesh is
unaffected.
2.4
dried salted fish: salted fish which have been dried.
2.5
food additives: additives added to the fish to preserve flavour and enhance its taste
and appearance (refer to Food Additives in Clause 5).
2.6
foreign material: any substance not naturally belonging in/on the fish.
2.7
lot acceptance: amount accepted as required by the standard.
2.8
salted fish: fish which have been treated by either brining, brine injection, drysalting, pickling or wet-salting or a combination of these.
2.9
salt: food grade sodium chloride (which may be iodized).
2.10 safe and wholesome: refers to fish that has been passed as being fit for human
consumption using the criteria that it:
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DGYS/XXX/2016
a) will not cause food borne infection or intoxication when properly handled and
prepared [with respect to the intended use];
b) does not contain residues in excess of established limits [elaborated as maximum
residue limits by the Codex Alimentarius Commission];
c) is free of disease, particularly those of zoonotic or animal health importance;
d) is free of obvious contamination;
e) is free of defects that are generally recognized as objectionable to the consumer;
f) has been produced under adequate hygiene control; and
g) fulfills the expectation of the consumer in regard to composition [and method of
production.]
2.11 wet salted fish: fish that was mixed with suitable food grade salt and stored under
the resultant brine which forms by solution of salt in water extracted from the fish
tissue.
3
Description
3.1
Product definition
Salted Fish is the product obtained from fish
(a) inclusive of the species listed in Appendix A; and
(b) which has been bled, gutted, beheaded, descaled, split or filleted, washed, salted.
Note: Washing shall be carried out with treated water (10floz/ 450gal of water or
295.735ml/ 1703.44L of water)
Dried Salted Fish is salted fish which have been dried.
3.1.1 Preparation of Fish for salting
To salt effectively, fish shall be prepared so that water removal and salt uptake can
take place quickly and easily. The following guidelines shall therefore be followed:
(i)
The thickness of flesh of the fish must not be more than 25 to 30 mm
(about 1 inch);
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DGYS/XXX/2016
(ii)
Small, whole fish need only be gilled and gutted if they are
thinner than this, medium-sized fish should be split through the back,
then gilled and gutted;
(iii)
Large fish can either be filleted, with the skin left on or split and the
flesh scored deeply at 25mm (1 inch) intervals;
(iv)
Very large fish must be filleted and the flesh cut into 25 mm (1 inch)
strips;
It is best to scale the fish, because the removal of water and
penetration of salt will be easier.
(v)
3.2
Process definition
The product shall be prepared by one of the salting processes (defined in 3.2.1) and
one or both of the drying processes (defined in 3.2.2) and according to one type of
presentation (as defined in 3.3.)
3.2.1 Salting
(a) Dry Salting (Kench Curing) is the process of mixing fish with suitable Food
Grade Salt and stacking the fish in such a manner that the excess of the resulting
brine (pickle) drains away.
Dry salting is recommended for Lean fish, e.g., Morocut, Shark. The process for
Dry salting shall be as follows:
1. Separate each layer of fish by layers of salt and place it in a container with
cut out sides, enabling the draining of the juice. First layer being the fleshside up, and the next layer being the flesh-side down. For two (2) parts of
fish, use one (1) part of salt. The final layer shall be salt.
2. Place a lid on top of the stack of fish with sufficient weight to press the
fish down. This allows for faster salt penetration and water removal.
3. The fish shall be restacked, or re-packed, every twenty-four (24) hours,
so that the fish previously on top now end up on the bottom. More salt
shall be added as required. This is done to provide uniform salting and
pressure which helps squeeze water out of the fish. Salting time varies
from three (3) days to a week, depending on the type and size of fish.
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DGYS/XXX/2016
Upon completion of drying, the excess salt shall be brushed off, and place in a
neatly sealed container. It shall be stored in a cool place, away from sunlight.
The fish shall be inspected at regular intervals while in storage. If during
periods of damp weather the dried salted fish show signs of moisture, it shall
be given a few hours of air drying. If signs of rust and mould appear, the fish
shall be scrubbed in light salt brine containing some vinegar, then spread
out to dry in the air for a day or two. The product shall last for many months.
(b) Wet Salting (Pickling) is the process whereby fish is mixed with suitable Food
Grade Salt and stored in watertight containers under the resultant brine (pickle)
which forms by solution of salt in the water extracted from the fish tissue. Brine
may be added to the container. The fish is subsequently removed from the
container and stacked so that the brine drains away.
Fatty fish, for example, Mackerel are best salted using the wet salting. Brining
and Pickle curing are the two methods used for Wet Salting. Identifying the type
of method used shall depend on whether the product will be further processed
by Drying or Smoking, or just preserved with Salting.
Brine Preparation
Mix four (4) parts of clean water and one (1) part salt (for example, 10L (2 gals)
of clean, fresh water to 2.7-3.6 kg (6-8lbs of dry salt) in clean large plastic drum.
Keep adding Salt to the water, until no more Salt will dissolve.
Brining
The process for brining shall be as follows:
1. Remove the head, backbone and scales of the fish before soaking in the
brine. Where the flesh is thick, slashes shall be made to ensure the salted
brine penetrates the flesh; very large fish shall be cut into thin fillets.
2. Keep the fish submerged (below the surface) in the brine. Stir the mixture
every twenty (20) to thirty (30) minutes. Brining will take as little as
thirty (30) minutes for light salting, or up to twenty-four (24) hours for
medium salting. Fish for drying, smoking and canning are usually brined
prior to processing.
Note: Fish shall be prepared according to its size, before it is placed in the brine.
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DGYS/XXX/2016
Pickle Curing
Pickle curing entails preparing the fish according to its size. The fish are then
laid alternately with dry salt in a water-tight container, such as a plastic
container, using a fish-to-salt ratio of one (1) part fish to 0.3 or 0.4 parts salt by
weight. That is, for 10kg of prepared fish, use 3-4kg of clean, dry salt. If less salt
is used, then the fish will spoil. The process for pickle curing shall be as follows:
1. The quantity of fish and salt needed are weighed.
2. A layer of gutted, opened and washed fish pieces shall be placed flat on
the salt, flesh side down; that is, flesh to flesh and skin to skin. After each
layer of
fish a thin layer of salt shall be sprinkled on it until all of the weighed fish
and salt is finished.
3. Finish the process with a layer of fish, skin upwards, and a final layer of
salt.
Note: Water from the fish will quickly start to form. The surrounding salt will
dissolve in this water. This is called the pickle. It is retained inside the
container and will eventually cover all the fish.
4. The fish is submerged until salting is completed. This process shall take
thirty-six (36) to forty (40) hours for small, whole fish and three (3) to
four (4) days for large pieces of fish.
Note: Wet salted fish should be consumed within two (2) months when stored at
ambient Temperature. It will keep for several months if stored in a cool place.
Fatty fish are best salted using the Wet Method. Recommended fish for this process
is Mackerel.
(c) Brine injection is the process of directly injecting brine into the fish flesh and is
permitted as a part of the heavy salting process.
3.2.2
Drying
(a) Natural Drying – the fish is dried by exposure to the open air two (2) to four (4)
days (see Figure 1 and 2); and
(b) Artificial Drying – the fish is dried in mechanically circulated air, the
Temperature (25-40oC) and Humidity (50-65% Rh) of which may be controlled.
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DGYS/XXX/2016
Figure 1 showing the construction of a Polythene Tent Dryer
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Figure 2 showing construction of Racks for natural drying
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DGYS/XXX/2016
3.2.2.1
Measuring the Drying Rate of Fish
When drying unsalted fish, a simple way to check the water loss is to weigh the fish
before and after drying:
 Lean fish such as Shark, should lose 75-76% of their original weight;
 Medium, Fatty fish, such as Tilapia should lose 72-73% of their original
weight;
 Fatty fish, such as Mackerel, should lose 67-68% of their original weight.
If the weight reduction takes longer than 2-3 days, under good drying conditions,
the fish is too thick. If the weight reduction is so low that the fish spoil, the fish will
have to be discarded.
3.3
Presentation
3.3.1 Split Fish – split and with the major length of the anterior of the backbone removed
(about two-thirds).
3.3.2 Split Fish with entire backbone – split with the whole of the backbone not
removed.
3.3.3 Fillet – is cut from the fresh fish, strips of flesh is cut parallel to the central bone of
the fish and from which fins, main bones and sometimes belly flap is removed.
3.3.4 Other Presentation: any other presentation of the product shall be permitted
provided that
(i)
(ii)
(iii)
it is sufficiently distinctive from the other forms of presentation laid down in
this standard
it meets all other requirements of this standard; and
it is adequately described on the label to avoid confusing or misleading the
consumer.
3.3.5 Individual containers shall contain only one form of presentation from only one
species of fish.
4
Essential Composition and Quality Factors
4.1
Fish
Salted Fish should be prepared from safe and wholesome fish, fit for human
consumption.
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DGYS/XXX/2016
4.2
Salt
Salt used to produce salted fish shall be clean, free from foreign matters and foreign
crystals show no visible signs of contamination with dirt, oil, bilge or other
extraneous materials and comply with the requirements laid down in Section 11 of
the Code of Practice for Fish and Fishery Products (CAC/RCP 52-2003).
Salt Requirements
-
-
-
The quality of salt used in salting of fish shall possess an appropriate
composition for the product;
The composition of the salt differs according to the origin. Mine salt and solar
salt of marine origin contain several other salts like Calcium sulphate,
Magnesium sulphate and Chloride as impurities. Vacuum processed and refined
salt is almost pure sodium chloride;
A relatively pure salt is needed for the dry-salting of fatty fish but for some
products the presence of small quantities of calcium salts will give the product a
somewhat superior appearance. Too much calcium may reduce the rate of salt
penetration to an extent that spoilage may occur;
-
Magnesium salts if present at too high a concentration will give rise to
unpleasant bitter flavours and may cause spoilage during the salting operation;
-
Salt produced from marine sources may contain halophilic bacteria and mould
which continue to live in the salt and dry salted fish and could contribute to
spoilage;
-
Salt used in salt fish should be inspected to ensure that it is clean, not used
before, free from foreign matter and foreign crystals, show no visible sign of
contamination with dirt, oil bilge or other extraneous materials;
-
The size of the salt granules used should be carefully considered. The use of very
fine salt granules could result in the formation of clusters which is not
favourable for ensuring the uniform distribution of salt on the fish. The use of
very coarse salt granule could result in damage to the fish flesh during salting
and may reduce the rate of maturation;
-
Small crystals of salt should be used for dry-salting of fatty fish and large crystals
for lean fish;
-
Salt used as an ingredient needs to be of Food Grade and may contain Iodine.
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4.3
Final Product
Products shall meet the requirements of this Standard when lots examined in
accordance with Section 10, comply with the provisions set out in Section 9.
Products shall be examined by the Methods given in Section 8.
5
Food Additives
Only the use of following additives is permitted.
Additives
Preservatives
E200 Sorbic acid
Maximum level in the final product
200 mg/kg, singly or in combination
expressed as sorbic acid
E201 Sodium sorbate
E202 Potassium sorbate
No butylated hydroxytoluene (BHA), butylated hydroxyanisole (BHT) or galate shall be
used in the salting process of fish.
6
Packaging Materials
6.1
Salted Fish and Dried Salted Fish shall be packaged in Food Grade containers which
will safeguard the hygienic, nutritional, technological and organoleptic qualities of
the product.
6.2
Packaging materials shall be made of substances which are safe and suitable for its
intended use, protect the product from substances harmful to health, and
accommodate proper labelling.
6.3
Packaging materials shall be strong enough to protect the fish and not affect the
taste or smell of the fish.
6.4
Suitable containers/ materials are wooden and cardboard boxes with lids or
polythene bags.
Note: Fish stored in plastic or polythene bags shall be stored at reduced
Temperatures.
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7
Hygiene and Handling
7.1
The final product shall be free from any foreign material that poses a threat to
human health.
7.2
When tested by appropriate Methods of Sampling and Examination prescribed by
the Codex Alimentarius Commission, the product:
7.3
(i)
shall be free from microorganisms (e.g. fungus, moulds) or substances (e.g.
slime) originating from microorganisms in amounts which may present a
hazard to health in accordance with standards established by the Codex
Alimentarius Commission;
(ii)
shall not contain any other substance (e.g. dust, bird droppings, insect pests,
parasites) in amounts which may present a hazard to health in accordance
with standards established by the Codex Alimentarius Commission.
It is recommended that the products covered by the provisions of this standard be
prepared and handled in accordance with the appropriate sections of the GCP
32:2010 – Code of Practice for General Principles of Food Hygiene and the
appropriate sections of the Code of Practice for Fish and Fishery Products (CAC/RCP
52-2003).
Handling, Storage and Transport
•
•
•
Procedures shall be in place to:
Sort food and food ingredients to segregate material which is evidently unfit for
human consumption;
Dispose of any rejected material in a hygienic manner, and
Protect food and food ingredients from contamination by pests, or by chemical,
physical or microbiological contaminants or other objectionable substances during
handling, storage and transport.
Care should be taken to prevent, so far as reasonably practicable, deterioration and
spoilage through appropriate measures which may include controlling temperature,
humidity, and/or other controls.
8
Labelling
In addition to the provisions of the GYS 9-9:2013- Specification for Labelling of prepackaged Foods, the following specific provisions apply:
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8.1
The Name of the Food
8.1.1 The name of the food to be declared on the label shall be “Salted Fish”, “Wet Salted
Fish” or “Salted Fillet” “Dried Salted Fish” or “Klippfish” or other designations
according to the law, custom or practice in the country in which the product is to be
distributed. In addition, there shall appear on the label in conjunction with the
name of the product, the name of the species of fish from which the product is
derived.
8.1.2 For forms of presentation other than those described in 3.3.1 “Split Fish”, the form
of presentation shall be declared in conjunction with the name of the product in
accordance with sub-section 3.3.2 as appropriate. If the product is produced in
accordance with sub-section 3.3.3, the label shall contain in close proximity to the
name of the food, such additional words or phrases that will avoid misleading or
confusing the consumer.
8.1.3 The term “Klippfish” can only be used for dried salted fish which has been prepared
from fish which has reached 95% salt saturation prior to drying.
8.1.4 The term “Wet Salted Fish” can only be used for fish fully saturated with salt.
8.2
Labelling of Non-retail Containers
Information specified above shall be given either on the container or in
accompanying documents, except that
 the name of the food,
 lot identification, and
 the name and address of the Manufacturer or Packer shall always appear on
the container.
However, lot identification, and the name and address may be replaced by an
identification mark, provided that such a mark is clearly identifiable with the
accompanying documents.
9
Sampling, Examination and Analysis
9.1
Sampling
(i)
Sampling of lots for examination of the product shall be in accordance with
an appropriate sampling plan with an Acceptable Quality Level (AQL) of 6.5.
A sample unit shall be the primary container or where the product is in bulk,
the individual fish is the sample unit.
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(ii)
9.2
ampling of lots for Net Weight shall be carried out in accordance with the
FAO/WHO Sampling Plans for the Determination of Net Weight (under
elaboration).
Sensory and Physical Examination
Samples taken for Sensory and Physical Examination shall be assessed by persons
trained in such examination and in accordance with procedures elaborated in
Appendix B and in accordance with Guidelines for the Sensory Evaluation of Fish
and Shellfish in Laboratories (CAC/GL 31 – 1999).
9.3
Determination of Net Weight
The net weight (excluding packaging material and excess salt) of each sample unit in
the sample lot shall be determined. Determination should be performed at least in
duplicate.
9.4
Preparation of Fish Sample
1. Before preparation of a sub-sample adhering salt crystal should be removed by
brushing from the surface of the sample without using water.
2. The preparation of Fish samples for the determination of Salt Content (See
Appendix E), and Water Content in order to calculate the % Salt saturation of the
fish shall be carried out according to AOAC 937.07 (See Appendix C). The
analysis should be on the edible portion of the fish.
9.5
9.6
Determination of Water Content
i)
Determination of % Salt saturation as required by the standard, shall be in
accordance to AOAC 950.46B (Air drying (a)). See Appendix F.
ii)
Determination of Water Content in the Whole Fish, when needed in the
commercial trade of Klippfish and Wet Salted Fish, the method of sampling
the fish shall be carried out according to the “Determination of Water
Content in Whole Fish by Cross Section Method” defined in “Appendix D”.
Determination of Salt Content
Determination of Salt content as required by the Standard shall be in accordance
with the procedure outline in Appendix E.
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9.7
Determination of Toxic Heavy Metals
Determination of toxic Heavy Metals as required by the Standard shall be in
accordance with the procedure outline in Appendix F.
9.8
Determination of Acid Insoluble Ash
Determination of Acid Insoluble Ash as required by the Standard shall be in
accordance with the procedure outline in Appendix G.
10
Definition of Defectives
10.1 The sample unit shall be considered defective when it exhibits any of the properties
defined below.
10.1.1 Foreign matter (Salted and Dried)
The presence in the sample unit of any matter (e.g. wood chips, bird droppings)
which has not been derived from fish, does pose a threat to human health, and is
readily recognized without magnification or is present at a level determined by any
method including magnification that indicates non-compliance with good
manufacturing and sanitation practices.
10.1.2 Odour (Salted and Dried)
A fish affected by persistent and distinct objectionable odours indicative of
decomposition (such as sour, putrid, etc) or contamination by foreign substances
(such as fuel oil, cleaning compounds, etc.).
10.1.3 Pink/ Reddening (Salted and Dried)
Any visible colouring due to red halophilic bacteria on the salted fish.
10.1.4 Texture (Dried)
Textural breakdown of the flesh which is characterized by extensive cracks on more
than 2/3 of the surface area or which has been mutilated, torn or broken through to
the extent that the split fish is divided into two or more pieces but still held together
by skin.
10.2 The sample unit shall be considered defective when 30% or more of the fish in the
sample unit are affected by any of the following defects.
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10.2.1 Halophilic Mould (dun) (Salted)
An aggregate area (on more than 1/3 of the total surface area of the face side) of
light brown or fawn spots on the salted fish due to pronounce halophilic mould
clusters.
10.2.2 Liver stains (Salted and Dried)
A pronounced yellow or yellowish orange discolouration caused by the presence of
liver and affecting more than ¼ of the total surface area of the face of the fish.
10.2.3 Intense bruising (Salted and Dried)
Any fish showing more than ½ of the face of the fish with intense bruising.
10.2.4 Severe burning (Dried)
A fish showing more than ½ of the back (skin side) tacky or sticky due to
overheating during drying.
10.3 Heavy metals (Salted and Dried)
The product shall be free from heavy metals in amounts, which may represent a
hazard to human health.
11
Lot Acceptance
A lot shall be considered as meeting the requirements of this standard when:
(i)
the Total Number of defectives as classified according to Clause 9 does not
exceed the acceptance number (c) of an appropriate sampling plan with an
AQL of 6.5;
(ii)
the Average Net Weight of all sample units is not less than the declared
weight , provided no individual container is less than 95% of the declared
weight; and
(iii)
the Total Number of Sample Units not meeting the form of presentation as
defined in Section 3.3 does not exceed the acceptance number (c) of an
appropriate sampling plan with an AQL of 6.5;
(iv)
the Food Additives, Hygiene and Handling and Labelling Requirements of
Clauses 5, 6 and 8 are met.
(v)
Heavy Metals should not exceed:
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HEAVY METALS
Heavy Metal
Mercury
Lead
Arsenic
Cadmium
ppm
0.5
0.3
0.01
0.05
DGYS/XXX/2016
Appendix A
Common Name
Catfish
Cavali
Cuirass
Cuma Cuma
Gill backer
Kukwari
Lou lou
Thomas fish
High water
Houri
Mackerel, King
Mackerel, Serra
spanish
Morocut/
Tambaqui
Pagi
Shark, Blacktip
Shark, Carib
sharp nose
Sharks,
Hammerhead
Snapper, Lane
Snapper,
Southern red
Snapper,
Vermillion
Tilapia
Weakfish,
Acoupa (Grey
snapper)
Weakfish, King
(Bangamary)
Weakfish, Green
(Sea trout)
List of Species of Fish used for Salting
Scientific Name
Unscaled/Scaled Fatty/dark Medium/low
Fish
Fat
Bagre bagre
Unscaled
Caranx hyppos
Unscaled
Arius proops
Unscaled
Arius couma
Unscaled
Arius parkeri
Unscaled
Arius phrygiatus
Unscaled
Arius species
Unscaled
Arius grandicassis
Unscaled
Hypopthalumus
Scaled
edentatus
Hoplias malabaricus
Scaled
Scomberomorous cavalla
Scaled

Scomberomorus
Scaled

brasiliensis
Colossoma macropomum
Scaled
Lean









White
Fish












Lobotes surinamensis
Carcharhinus limbatus
Rhizonoprionodon
porosus
Sphyrnidae
Scaled
Scaled
Scaled






Scaled


Lutjanus synagris
Lutjanus purpureus
Scaled
Scaled




Rhomboplipes aurorubns
Scaled


Oreochromis niloticus
Cynoscion acoupa
Scaled
Scaled




Macrodon ancylodon
Scaled
Cynoscion virescens
Scaled




DGYS/XXX/2016
Appendix B
Sensory and Physical Examination for Fish for Processing
B1
Examine every fish in the sample in its entirety for safeness and wholesomeness.
B2
Examine the product for the form of presentation.
B3
Examine the fish for Foreign Matter, Pink conditions, Halophilic mould, Liver stains,
intense Bruising, severe Burning and Texture.
B4
Assess Odour in accordance with the Guidelines for the Sensory Evaluation of Fish
and Shellfish in Laboratories (CAC/GL 31 – 1999).
B5
Sensory Evaluation
B 5.1 The best way of assessing the freshness/spoilage of fish is by sensory evaluation
techniques. It is recommended that sensory evaluation charts be used to verify the
acceptability of fresh fish and to eliminate fish showing an unacceptable level of
decomposition.
Quality Parameter
General Appearance
Character
Skin
Gills
Stiffness
Belly
Smell
Eyes
Clarity
Shape
Properties
Bright and shining, should not be dull gritty
colours with yellow brown dotting slime.
Should be bright red and free from slime.
None should be present or any abnormal colour,
slime opaque yellow, thick or clotting.
Should not be Stiff, in rigor mortis
Should be Firm not soft or with belly burst.
Should be fresh (fishy but mild), not sour or stale
meat/rancid.
Clear not Cloudy.
Normal not Sunken.
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Appendix C
Sample Preparation of Fish
C1
Precautions for Sample Preparation of Fish
C 1.1 To prevent loss of water during preparations and subsequent handling, use samples
as large as practicable. Keep ground material in container with air-tight cover and
begin all analysis as soon as practicable. If any delay occurs, chill sample to inhibit
decomposition.
C2
Sample Preparation for Fresh Fish
C 2.1 Clean, scale and degut fish.
C 2.2 For small fishes ≤ 15 cm use 5-10 fishes and for large fishes use ≥ 3 fishes (sample
collection). Cut 3 cross-sectional slices 2.5 cm thick, 1 slice from just back of pectoral
fins, 1 slice halfway between first slice and vent and 1 slice just back of vent.
C 2.3 Remove the bones. (For intermediate fishes, discard heads, scales, tails, fins and
inedible bones).
C 2.4 Fillet fish to obtain all flesh and skin from head to tail and from top of back to belly
on both sides. For determination of fat and fat-soluble components, skin must be
included, since many fish store large amounts of fat directly beneath the skin.
C 2.5 Place sample into a high speed blender and blend several minutes stopping blender
frequently to scrape down sides of cup.
C3
Fish packed in Salt or Brine
C 3.1 Drain, discard brine and rinse off adhering salt crystals with sodium chloride
standard solution.
C 3.2 Drain again for 2 minutes and proceed as in C 2.2.
C4
Dried Salted Fish
Proceed as in C 2.2.
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Appendix D
Determination of Water Content in Whole Salted Fish by Cross section Method
D1
Principle
D 1.1 The fish is cut in sections as described in method. The sections are cut in smaller
bits to a collected sample. The water content of the collected sample is determined
by drying. Examinations and experience have shown the water content of this
collected sample is closed to the “true” water content of the fish.
D2
Equipment
-
D3
Soft brush
Basins (steel, glass, porcelain)
Scissors
Band saw
Knife
Balance, 1 g precision
Oven 103-1050C
Desiccator
Preparation of Sample
D 3.1 Salt particles on the surface of the fish are brushed away.
D 3.2 The weight of the fish is determined (to 1g accuracy).
D 3.3 The length of the fish is measured as the distance between the cleft in the tail and a
line drawn between the tips of the earbones.
D4
Procedure
D 4.1 The sampling of the Fish is described in the Figure 3.
D 4.1.1
Wet Salted Fish is sliced in sections by knife
D 4.1.2
Salted and Dried Salted Fish is sliced in sections by Band saw.
D 4.1.2.1
A section of 20 mm measured from a line drawn between the earbones,
dotted line on figure, is cut.
D 4.1.2.2
The next cut is a 40 mm section.
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DGYS/XXX/2016
D 4.1.2.3
A 2 mm section is cut from the front part of the 40 mm section and collected
(see D 4.1.2.7)
D 4.1.2.4
The next cut is a new cut of a 40 mm section.
D 4.1.2.5
A 2 mm section is cut from the front part of the 40 mm section and collected.
D 4.1.2.6
The entire fish is cut in 40 mm sections from which are cut 2 mm sections
(see Figure 3).
D 4.1.2.7
All sections of 2 mm, marked II, IV, VI, and VIIΙ in Figure 2, even numbers, are
collected to a collected sample.
D 4.2 The 2 mm sections in the collected sample are cut with scissors in smaller pieces
directly in tared basins just after the fish is cut.
D 4.3 The basins containing the sample are weighed.
D 4.4 The basins containing the samples are put in the oven at 103 - 1050 C for drying to
constant weight (18 hours over night).
D 4.5 The basins are taken from the oven to a desiccator and cooled.
D 4.6 The basins are reweighed.
D5
Calculation of Results
In the equation of the calculation of results the following symbols are used:
W1 = Weight of Fish and Basins before Drying, g.
W2 = Weight of Fish and Basins after Drying, g.
Ws = Weight of tared Basins, g.
The Water Content in the fish is calculated by using the equation:
Water Content (expressed as g/100g) = 100* W1-W2
W1 – Ws
The result is reported to the nearest gram, together with the length and the weight
of the analysed fish. For example: 15g (50cm, 240g)
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Figure 3 showing Sampling Procedure of the Fish
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D6
Control Analysis of Whole Fish
D 6.1 The determination of Water Content in Whole Fish by Cross section Method appears
to give the closest result compared to Water Content determined by the drying of
the whole fish (ALINORM 03/18, Appendix IX).
D7
Comments
D 7.1 Each sampled fish should be packed and sealed in a plastic bag before analysis. The
samples should be stored under chilled or refrigerated conditions from the time of
sampling to the time of analysis.
D 7.2 The analysis must be performed as soon as possible after the fish has been sampled.
D 7.3 It might be difficult to cut sections of 2 mm when the fish has water content above
50% but the section must be close to 2 mm.
D 7.4 To minimize the loss of water from the 2 mm sections it is important to weigh the
collected sample immediately after the fish is cut in sections.
D 7.5 Determination should be performed at least in duplicate.
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Appendix E
Determination of Salt Content
E1
Principle
The salt is extracted by water from the pre-weighed sample. After the precipitation
of the proteins, the chloride concentration is determined by titration of an aliquot of
the solution with a standard silver nitrate solution (Mohr Method) and calculated as
sodium chloride.
E2
Equipment and Chemicals
-
E3
Brush
Sharp knife or saw
Balance, accurate 0.01g
Calibrated Volumetric Flasks, 250ml
Erlenmeyer Flasks
Electric homogenizer
Magnetic Stirrer
Folded paper filter, quick running
Pipettes
Funnel
Burette
Potassium hexacyano ferrate (II), K4Fe(CN)6.3H2O, 15% w/v (aq)
Zinc sulphate, ZnSO4.6H2O, 30% w/v (aq)
Sodium hydroxide, NaOH, 0.1 N, 0.41% w/v (aq)
Silver nitrate, AgNO3, 0.1 H, 1.6987% w/v (aq), standardized
Potassium chromate, K2CrO4 5% w/v (aq)
Phenolphthalein, 1% in ethanol
Distilled or deionized water
Procedure
E 3.1 5g of Homogenized sub-sample is weighted into a 250ml Volumetric flask and
vigorously shaken with approximately 100 ml water.
E 3.2 5ml of Potassium hexacyano-ferrate solution and 5ml of Zinc sulphate solution are
added, and the Flask is shaken.
E 3.3 Water is added to the graduation mark.
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E 3.4 After shaking again and allowing to stand for precipitation, the Flask content is
filtered through a fluted Paper filter.
E 3.5 An aliquot (10ml) of the clear filtrate is transferred into an Erlenmeyer Flask and
two (2) drops of Phenolphthalein are added. Sodium hydroxide is added drop wise
until the aliquot takes on a faint red colour. The aliquot then diluted with water to
approximately 100 ml.
E 3.6 After addition of approximately 1ml Potassium chromate solution, the diluted
aliquot is titrated under constant stirring, with silver nitrate solution. Endpoint is
indicated by a faint, but distinct, change in colour. This faint Reddish-brown colour
should persist after brisk shaking.
E 3.7 Blank titration of Reagents used should be done.
E 3.8 Endpoint determination can also be made by using instruments like potentiometer
or colorimeter.
E4
Calculation of Results
In the equation of the calculation of results the following symbols are used:
A= Volume of aliquot (ml)
C= Concentration of silver nitrate solution in N
V= Volume of silver nitrate solution in ml used to reach endpoint and corrected
for Blank value
W= Sample Weight (g)
The salt content in the sample is calculated by using the equation:
Salt concentration (assessed as %) = (V x C x 58.45 x 250 x 100) / (A x W x 1000)
Results should be reported with one figure after the decimal point.
E5
Reference Method
E 5.1 As Reference Method should be used which includes the complete ashing of the
sample in a Muffle Furnace at 5500C before Chloride determination according to the
Method described above (leaving out steps (ii) and (iv)).
E6
Comments
E 6.1 By using the given equation all Chloride determined is calculated as Sodium
chloride. However it is impossible to estimate sodium by this methodology, because
other chlorides of the alkali and alkali earth elements are present which form the
counterparts of chlorides.
E 6.2 The presence of natural halogens other than Chloride in fish and salt is negligible.
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6.3 A step, in which proteins are precipitated (ii), is essential to avoid misleading
results.
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Appendix F
Moisture in Fish (Air Drying Method)
F1
Apparatus and Materials
F 1.1
F 1.2
F 1.3
F 1.4
F 1.5
F 1.6
Aluminum dishes: ≥ 50 mm diameter & ≤ 40 mm deep
Air Oven
Desiccator
Analytical Balance
Spatulas
Knives
F2
Procedure
F 2.2 Air Oven Drying Method
F 2.2.1
Weigh 2 g of dry sample into the aluminum dish
F 2.2.2
Heat sample at 100-1020C for 16-18 hrs in the Air Oven
F 2.2.3
Cool in a desiccator and weigh
F 2.2.4
Record reading and report as loss in weight (moisture).
F 2.3 Alternative Air Drying Method
F 2.3.1
Weigh 2 g (± 1mg) of dry sample into the aluminum dish to constant weight
for 2-4 hrs in a gravity oven at 1250C
F 2.3.2
Avoid excessive drying
F 2.3.3
Cover and cool in desiccators and weigh
F 2.3.4
Record reading and report as loss in weight (moisture)
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Appendix G
Determination of Acid Insoluble Ash
G1
Reagent
G 1.1 Dilute Hydrochloric Acid- 1:1, prepared from concentrated hydrochloric acid.
G2
Procedure
G 2.1 Weigh accurately about 2g of the dried material in a tared porcelain, silica or
platinum dish. Ignite with a meker burner for about one (1) hour. Complete the
ignition by keeping in a muffle furnace at 500 0C to 570 0C until grey ash results.
G 2.2 Cool and filter through whatman filter paper No. 42 or its equivalent. Wash the
residue with hot water until the washings are free from chlorides as tested with
silver nitrate solution and return the filter paper and residue to the dish. Keep it in
an electric air oven maintained at 135 ± 2 0C for about three (3) hours. Ignite the
dish again for about thirty (30) minutes, cool and reweigh. Repeat this process till
the difference between two successive weights is less than 1 mg. note the lowest
weight.
G3
Calculation
G 3.1 Acid insoluble ash, per cent by weight
= 100 (M2 – M
M1 - M
Where,
M2 = the lowest weight, in g, of the dish with the acid insoluble ash;
M = weight, in g, of the empty dish; and
M1 = weight, in g, of the dish with the dried product taken for the test.
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