ACKNOWLEDGEMENT
This manual was developed through the support of the
HealthyFoodAfrica (HFA) project, a European Union (EU) Horizon
2020 collaborative research project funded by the European Union,
coordinated by the Institute of Natural Resources, Finland (LUKE)
and carried out at the CSIR-Food Research Institute. We appreciate
the cooperation of the management and directors of the CSIR-Food
Research Institute and the CSIR-Water Research Institute
CONTENT
ACKNOWLEDGEMENT… ................................................. i
INTRODUCTION… ............................................................. 1
GOOD HYGIENIC PRACTICES ......................................... 3
PROCESSING OF SMOKED FISH….................................. 7
CONCLUSION… ................................................................. 22
INTRODUCTION
Smoking is another method of preservation for fish that is often used in
African countries. It accounts for about 70 to 80% of the most common
fish preservation and processing methods in Africa which enables long
storage and trading to other markets. Smoking has been described as the
penetration of volatiles produced from the thermal destruction of wood
into fish products. Wet-hot smoking and dry-hot smoking are the forms
it takes with both taking place at temperatures high enough to cook the
fish. The type of fish, the required storage period, and its intended usage
determine which form to apply. For wet-hot smoking, the fish is smoked
for about 2 hours to a final moisture content of about 40-50% and can be
stored for 3 days. In the dry-hot smoking method, on the other hand, fish
is smoked for about 18 hours and can have 10-15% moisture content.
This gives the fish a longer storage life of up to about 9 months. The heat
is produced from the burning of fuel which includes hardwood, sawdust,
coconut shell, husk and other local sources of fuel. The incomplete
combustion of these fuel sources generates smoke which also contains
gases, chemical and flavour compounds. The smoking is carried out in
indigenous earthen kilns, bricks, and metal/oil drums with single or
multiple platforms above the combustion chamber on which the fish is
loaded. A very popular one is the Chorkor oven from Ghana.
Smoked fish is nutritious and as such its consumption is necessary to
alleviate the micronutrient deficiencies in Africa. The smoking process
improves the sensory attributes of the fish, increases shelf life and
utilization. The high smoking temperatures can inhibit microbial growth
ensuring food safety. Denaturing of protein may also occur and phenolic
compounds slow down oxidation of fish lipids. The degree to which the
fish is coloured and flavoured is correlated with the amount of smoke
intake. Smoking may also lead to the production of carcinogenic
substances like polycyclic aromatic hydrocarbons (PAHs) in the fish.
The Food and Agriculture Organization introduced the FAO-Thiaroye
Technology/FAO-Thiaroye Processing Technique (FTT) oven as an
intervention oven which uses fully-lit charcoal mixed with heat retention
stones for fish smoking. It can mitigate most of the negative effects of
traditional ovens. Low PAH (benzo(a)pyrene (BaP and PAH4) levels are
recorded from fish smoked in this oven meeting the EU regulatory limits.
The Ahotor (comfort) oven was also introduced in Ghana to achieve
similar outcomes as the FTT but has some challenges (including a slow
rate of smoking, and low turnover time) and hence requires further
improvement.
Under the Healthy Food Africa project, some modifications have been
carried out on the Ahoto oven (CSIR FRI/MA/AA/2024-002). The
improvement work focused on increasing the range of adoption by
different end users. The combustion has been modified to include a
chamber for charcoal briquettes as well as a built-in Liquefied Petroleum
Gas (LPG) system, allowing fish processors to use a variety of fuel
alternatives. This is also expected to significantly reduce PAH levels as
cleaner fuel options are provided. Depending on end-user preferences, a
fuel mix option could be used to improve the taste and texture of the final
product. The Chorkor oven was also modified to improve upon the PAH
levels and hygiene. The oven has been redesigned with the introduction
of a fat collecting system aimed at reducing fat drippings in the fire during
smoking. The fat collector introduced is expected to channel all forms of
drippings out of the oven and thereby reduce smoke production and
emissions. Therefore, this document addresses the hygienic handling of
fish, smoking in the modified, improved ovens, and packaging, to
produce fish that is safer and nutritious. The use of these techniques may
enhance the patronage of smoked fish and expand its local and export
markets.
GOOD HYGIENIC PRACTICES
Good hygiene practices (GHPs) are fundamental measures and
conditions applied at any step within the food chain to provide safe and
suitable food (FAO and WHO, 2023). GHPs control numerous food-
related risk sources that have the potential to contaminate food products.
These include workers who handle food during harvest, production, and
preparation; suppliers of raw materials and other ingredients; upkeep and
cleaning of the work area; and storage and even display. While all GHPs
are significant, some are more so in terms of their effect on food safety.
For instance, cleaning walls and ceilings is not as important as cleaning
equipment and surfaces that come into contact with ready-to- eat food.
This is because improper cleaning of surfaces that come into contact with
food can directly contaminate food. Every processor should be conscious
of the risks associated with the work and the key controls needed to
appropriately manage such risks. Some of these key controls include:
a. control of water quality – minimizes the presence of many
potential hazards (e.g. biological, chemical, physical);
b. control of faecal contamination – minimizes the potential for
contam-ination with many foodborne pathogens such as Salmonella,
Campylobacter, Yersinia, pathogenic strains of Escherichia coli;
c. control of food handler practices and hygiene – prevents many
poten-tial communicable diseases that could be foodborne; and
d. control of food contact surfaces by cleaning – removes bacterial
contaminants, including foodborne pathogens, and allergens (FAO and
WHO, 2023).
Some personal hygiene mistakes by processors can cause pathogens or
germs to be transferred to the fish being processed (FAO, 2012-Fish
handling, quality and processing: training and community trainers
manual (https://openknowledge.fao.org/handle/20.500.14283/az083e).
These include:
a. Failure to wear clean, protective clothing;
b. Failure to cover wounds;
c. Failure to wash hands after using the toilet;
d. Failure to wash hands before handling fish;
e. It is improper to spit, cough, or sneeze;
f. It is improper to allow fingernails to grow long;
g. It is improper to smoke;
h. It is improper to eat or drink while handling fish;
i. Fish handling when ill (vomiting, diarrhoea, skin infections) is
improper;
j. Wearing jewellery, such as bracelets, necklaces, earrings, watches, and
rings is improper.
Additionally, the following World Health Organization’s (WHO) 5 Keys
to Safer Foods, which focuses on the five fundamental messages that
explain the principles of good hygiene, offers detailed information on
how food hygiene must be taken into account to improve the quality and
safety of foods including fish and must be applied where applicable
(WHO 2006).
Table 1: WHO 5 Keys to Safer Foods
Keep clean Why?
✔ Wash your hands before handling While most microorganisms do not
food and often during food preparation cause disease, dangerous
✔ Wash your hands after going to the microorganisms are widely found in
toilet soil, water, animals and people.
These microorganisms are carried
✔ Wash and sanitize all surfaces and
on hands, wiping cloths and utensils,
equipment used for food preparation
especially cutting boards, and the
✔ Protect kitchen areas and food from
slightest contact can transfer them to
insects, pests, and other animals food and cause foodborne diseases.
Separate raw and cooked Why?
✔ Separate seafood, raw meat, and Raw food, especially meat, poultry
poultry from other foods and seafood, and their juices, can
✔ Use separate equipment and utensils contain dangerous microorganisms
such as knives and cutting boards for which may be transferred onto other
handling raw foods foods during food preparation and
storage.
✔ Store food in containers to avoid
contact between raw and prepared foods
Cook thoroughly Why?
✔ Cook food thoroughly, especially Proper cooking kills almost all
meat, poultry, eggs and seafood dangerous microorganisms. Studies
✔ Bring foods like soups and stews to have shown that cooking food to a
boiling to make sure that they have temperature of 70°C can help ensure
reached 70°C. Ideally, use a it is safe for consumption.
thermometer
✔ Reheat cooked food thoroughly
Keep food at safe temperatures Why?
✔ Do not leave cooked food at room Microorganisms can multiply very
temperature for more than 2 hours quickly if food is stored at room
temperature. By holding at
✔ Refrigerate promptly all cooked and temperatures below 5°C or above
perishable food (preferably below 5°C) 60°C, the growth of microorganisms
✔ Keep cooked food piping hot (more is slowed down or stopped. Some
than 60°C) prior to serving dangerous microorganisms still
grow below 5°C.
✔ Do not store food too long even in
the refrigerator
✔ Do not thaw frozen food at room
temperature
Use safe water and raw materials Why?
✔ Use safe water or treat it to make it Raw materials, including water and
safe ice, may be contaminated with
✔ Select fresh and wholesome foods dangerous microorganisms and
chemicals. Toxic chemicals may be
✔ Choose foods processed for safety,
formed in damaged and mouldy
such as pasteurized milk
foods. Care in the selection of raw
✔ Wash fruits and vegetables,
materials and simple measures such
especially if eaten raw as washing and peeling may reduce
✔ Do not use food beyond its expiry the risk.
date
(Adapted from CSIR-FRI/MA/AA/2021/001; WHO Permission request
ID: 373210)
6
PROCESSING OF SMOKED FISH
Characteristics of fresh and spoiled fish
A fish processor must know the characteristics of fresh fish and spoiled fish.
The difference between fresh and spoiled fish which the processor or
consumer may use as a guide in buying fish is key. With this guide, the
processor or consumers would be able to decide if the fish displayed for
sale should be accepted or rejected as shown in Table 2.
Table 2: Difference between Fresh and Spoiled Fish
FRESH FISH SPOILED FISH
EYES Bright, bulging, pupil velvet Dull, wrinkled, sunken
black, cornea transparent pupil dull black, cornea
opaque
GILLS Bright red, covered with clear Dull brown or grey, slime
slime; odour under gill covers cloudy; odour under gill
fresh covers sour and offensive
FLESH Firm, body is stiff, an Soft and flabby; an
impression made by fingers do impression made by
not remain; slime present is fingers remains
clear
BELLY Intact Often ruptured; viscera
WALLS protruding
MUSCLE White Pinkish, especially around
TISSUE the backbone
VENT Pink, not protruding Brown, protruding
ODOUR Fresh, fishy odour Stale, sour, or putrid
COLOUR Bright Faded
Adopted from: https://www.fao.org/3/ac061e/AC061E34.htm
7
Steps in the processing of smoked fish
Hands, contact surfaces, utensils and equipment must be washed with soap
and potable water before the start of activities in the facility. Staff must be
appropriately dressed. The steps involved in processing smoked fish are
shown in the flow diagram below.
RECEIVING/ PROCEDURE
STORAGE
When the fish arrives
(CONTROL
in boxes/
POINT)
containers/bowls,
they are
examined to ensure
the raw fish is
infused in ice or iced.
The fish is inspected
as a Control Point
(CP) to make sure it
is free of any
undesired materials.
Then the fish are
sorted based on the
following quality
checks:
1. Bad smell or fish
smell
2. Impaired eye
refractive index i.e.
dull eyes.
PAGE 9
3. Pale or Green
gills, which are
slimy.
4. Softness of the
fish tissue
5. Damaged or
injured fish.
It's then processed
further OR the fish
can be packaged,
labelled, and frozen
until ready to use.
Keep fish from
staying longer than
necessary via the
principle of "first in,
first out." This
storage temperature
is a CP to prevent or
eliminate a food
safety hazard.
Frozen fish can be
thawed at room
PAGE 10
temperature or in the
open for a few hours
hygienically. A
batch code has to be
generated for every
batch received. It
should include the
initial of the supplier,
the date of receipt,
and the time for
processing. It should
be well affixed on
the package.
FIRST The fish must be
WASHING
thoroughly washed
to eliminate the
majority of any
possible waste
materials, dirt, and
bacteria that may
have been associated
with any sand or dirt
that may have been
on its surface. Use
potable water
(potable running
water or stored
potable water) to
wash each fish
separately to ensure
that there is no
foreign material or
sand in its gills and
other parts.
Defrosted fish must
be washed severally
to get rid of any
leftover ice.
GUTTING AND Make an incision
GILLING
directly beneath the
(OPTIONAL)
fish's belly with a
clean, sharp knife to
open it. Physically
remove all the
stomach contents
thoroughly.
PAGE 12
Additionally,
remove all gill
covers by taking
them out of the
operculum with the
knife. Clean the fish
with potable water.
NB: This applies
only to fish types
that require gutting
and gilling.
SCALING AND Take off all of the
BEHEADIN G
fish's scales from
(OPTIONAL)
both sides using a
knife to remove
every last one from
the fish skin into a
bowl. The removal
of the heads from
fish may also be
carried out by
pressing the knife up
against the fish's
PAGE 13
head or gill cover,
the head is then cut
off from the body.
The fins may also be
removed.
NB: This applies
only to fish types
that require the
removal of scales,
head and fins.
2ND Wash the descaled
WASHING
fish in/under potable
water to get rid of all
of the fish skin's
loose scales.
PAGE 14
3RD Use 10% clean edible
WASHING salt water in a
(Control Point) bowl to wash for 3-5
min. This is critical
to prevent biological
pathogens' growth
during smoking/
drying and histamine
Formation (in
histamine-susceptible
species). It can also
prevent and enhance
The texture, flavour
and overall taste.
Dripping and drying
follows immediately
after.
OVEN Prepare the oven for
READINESS
the smoking process
by sprinkling ash on
the fat-collecting
trays.
SMOKING Arrange the fish on
(CRITICAL the trays, set/light
CONTROL the fire and smoke
POINT) for the amount of
time needed to coag-
ulate the proteins.
Insert a probe to
check the
internal temperature
of the fish (it should
be around 80 °C) for
the required duration
based on the fish size
and moisture
content. That is,
about 2 h to a final
moisture content of
PAGE 16
about 40-50% for
wet-hot smoked fish
and 18 h to a final
moisture content of
about 10-15% for
dry-hot smoked fish
or depending on the
specification of the
buyer). The smoking
stage is a Critical
Control Point (CCP).
This is a stage
critical for biological
pathogens' growth to
be prevented or
eliminated. At the
end of smoking,
quench the fuel
source/fire.
NB: There is a need
for moisture and
water activity
monitoring at this
stage.
PAGE 17
COOLING The fish is allowed to
(CRITICAL sufficiently cool on
CONTROL the oven at room
POINT) temperature
depending on the
size (maximum
overnight). Cooling
is critical to prevent
condensation in
packaging materials
which promotes
microbial growth.
Cooling must not be
too long as
pathogens can grow
on them.
PACKAGING Depending on the
AND suitability, fish is wei-
LABELING ghed and packaged
(CRITICAL in food grade clean
CONTROL brown paper-lined
POINT) boxes, baskets or
appropriately
labelled polythene/
PAGE 18
polyethene bags hygi-
enically indicating
the appropriate
temperature for
storage, handling,
and shelf life.
Packaging maintains
the product's
integrity and helps
avoid contamination.
Vacuum packaging
can also be done for
longer shelf life but
Clostridium spp
check may be
required.
NB: Customers feel
more confident when
they see labels on the
product.
PAGE 19
Pathogens can grow
STORAGE
(CONTROL in warm temperatures
POINT)
so must be stored and
transported hygienica-
lly. Wet-hot smoked
fish can be stored e.g
in the freezer while
dry-hot smoked fish
can be stored at room
Temperature.
CP/CCP: essential to prevent or eliminate a food safety hazard or reduce it to an
acceptable level.
Instructions for use
Add the desired quantity of smoked fish to stews and soups.
Heat and use as accompaniment.
Serving size
It contains a significant amount of proteins, but the fat and other nutrient content
can change depending on the fish species. Serving size may differ from person to
person but about 6 ounces cooked for a 160-pound/73 kg adult.
Raw material sources
All raw materials are obtained in the traditional open market and fish landing
sites.
Packaging
Different types of packaging are used for smoked fish in Ghana. The most
common being cane baskets lined with brown paper with nets put around the
PAGE 20
baskets to keep the fish in place. For the formal markets, smoked fish is
packaged in boxes, normally sealed pouches and vacuum packaging. Since
vacuum packing keeps out oxygen, it delays the development of rancidity in
fatty fish. Th packaging material must be of a food grade and clean. The packaging has
a critical role in determining the shelf life of fish. It must limit odour
permeation, minimize bacterial and chemical deterioration, suppress fat
oxidation, and dehydrate the product under normal conditions. Fish that has
cavities, is dehydrated, is discoloured, is rotten, and has some black or red
patches are signs of low quality.
Storage period and condition
Generally, the shelf life of smoked fish products varies based on several
factors, including the fish species, quantity of salt, fuel type, level or duration
of drying/smoking, storage temperature, storage condition, and type of
packaging material. A well dry-hot smoked fish can store for up to 9 months
while a wet-hot smoked fish can store for up to 3 days at room temperature.
They are however expected to last longer in the frozen state.
PAGE 21
CONCLUSION
It is important to maintain the hygienic processing of smoked fish to protect
the public's health as well as the reputation of the fish processing sector. We
can reduce the risk of contamination and maintain the end product's quality and
safety by adhering to good hygienic practices from start to finish of the
production chain. Good hygiene practices must be implemented to prevent the
growth of harmful microorganisms and the formation of toxins. These include
thorough cleaning and disinfecting equipment and facilities, handling and
storing raw materials properly, and routinely checking on key control points.
In addition, it is imperative that staff members engaged in the processing of
smoked fish get continual training and education to establish a culture of food
safety and guarantee adherence. By keeping up with emerging technologies
and best practices, we can reduce the risk of foodborne illness outbreaks.
Finally, prioritizing good hygienic practices during the processing of smoked
fish protects customers, boosts market competitiveness, and fosters trust and
confidence in the products. Maintaining the highest standards of food hygiene
and safety is a shared obligation of all stakeholders in the industry, protecting
the public's health and encouraging the sector's sustainable growth
PAGE 22
