Various problems associated with the quality of the fishery products like spoilage, discolouration, microbiological problems, etc., are outlined. The reasons and remedial measures are discussed. The importance of proper handling, processing and hygiene is stressed

Badonia, R.

Ramachandran, A.

Sankar, T.V.

Aquatic Commons

Journal of the Indian Fisheries Association 
18, 1988. 283-287 
QUALITY PROBLEMS IN FISH PROCESSING 
R.. BADONIA, A. RAMACHANDRAN AND T.V. SANKAR 
Veraval Research Centre of CIFT (Gujarat) 362 265. 
ABSTRACT 
Va'tious problems associated with the quality of the 
fishery products like spoilage, discolouration, microbiological 
problems, etc., have been outlined. The reasons thereof 
and remedial measures are discussed. The importance of 
proper handling, processing and hygiene has been underlined. 
INTRODUCTION 
Seafoods are highly perishable in nature. Unpredictability 
ot catch, uncontrolled harvesting, inadequate handling, processing 
and storage add up to the quality problems. The quality has 
to be maintained although the various stages till fish reaches 
the consumer. The quality problems arise mainly due to poor 
quality of raw material, ice and water, microbiological contami-
nation; presence of heavy metals and storage aspects. In the 
export market the buyers insist on high quality and due to 
Modified Inplant Quality Control (MIPQC) the situation is improv-
ing. But in the domestic market the quality of fresh, dried and 
cured f{sh remain yet to be improved. The important quality 
problems in the field of fish preservation and related aspects 
are discussed in this article .. 
MAINTENANCE OF FRESHNESS 
The intrinisic quality of fish varies with season, age, 
sex, maturity and many other factors. After the catch proper 
handling of fish is very important. The use of refrigerated sea 
water (R.S.W.) or chilled sea water (C.S.W.) is restricted to 
valued items like shrimp. Icing is prevalent for quality fish and 
ratio of ice varies with season and duration of fishing. With 
prop~r use of ice, shelf life of fish can be upto 8-10 days. 
BADONIA. RAMACHANDRAN -AND SANKAR 
Enough care should taken onboard by keeping the deck and 
fishhold clean and keeping the fish in shed. Major contamination 
takes place at the landing centre due to landing on unclean 
beanche, dirty jetty, throwing the fish around, use of bamboo 
backets and fish handlers. Gutting of bigger fishes onboard 
and bleeding will improve the quality. 
BLACK SPOT, PINK/YELLOW DISCOLOURATION 
Melanosis or black spot formation in shrimp and lobster is 
due to oxidative, enzymatic reaction, in which the amino acid 
tyrosine present in the material is oxidised to melanin by the 
enzyme tryorinase. The eating quality is not affected but the 
poor appearance reduces the price. As the enzyme is a concen-
trated in the head, beheading is useful. Keeping the material 
at chilled temperature and removing the oxygen or creating 
inert gas atmosphere control melanosis. Chemicals like ascorbic 
acid, sulphite and cysteine reduce black spot formation. Dip 
treatment for 2 minutes in 3000 ppm sodium or potassium meta 
bisulphite prev.ents black spot formation. Residual level of so2 in muscle should not exceed 100 ppm. 
Pink or yellow discolouration takes place in squid and cuttle 
fish due to processing delays. Immediate icing, gutting, removal 
of ink sac, proper handling. thorough washing and storage in ice 
will reduce discoloura tion. Pomfret and hilsa on frozen storage 
develop yellow discolouration which may be due to o~<idation 
of fat and lipid protein interaction during storage. Proper handling 
onbqard icing, gutting, glazing and antioxidant treatment reduce 
discolouration. 
MAINTENANCE OF QUALITY IN FROZEN FISH 
The quality of the frozen fish mainly depend on the quality 
of raw material, handling processing time and storage conditions. 
Fish must be landed as fresh as possible, with icing. During 
processing also fish should be kept under ice. F ille tting the 
fish in pre-rigor gives higher fillet yield, less dripless and gaping. 
Handling of post-rigor fish is easy and uniform quality is 
maintained. Frozen fish stored for long period shows soft texture, 
loss of flavour and taughness upon cooking. Due to denaturation 
of protein, water holding, emulsifying and lipid binding capacity 
of the muscle is reduced. Drip loss upon thrawing is considerable 
if the raw material used is not fresh. Polyphosphate treatment 
to reduce drip loss is not permitted. To maintain frozen fish 
QUALITY PROBLEMS IN FISH PRESERVATION 285 
quality fresh raw material must be frozen rapidly givmg proper 
glaze and wrapping in poly thene sheet. The storage should be 
at the lowest temperature with constant temperature and humidity 
control. In the frozen products objectionable matter like sand, 
fibers, paper, flies, excess shell and veins and antenne, hair 
and other filth should be removed during processing. Thus general 
quality problems like excess driploss, non-confirmity of grade, 
freezer burn and filth etc., can be avoided by proper care. 
MICROBIOLOGICAL QUALITY 
Fresh fish contains various types of microorganisms which 
are usually harmless to man. Bacteria are present in large numbers 
in fish in the slime, gills and gut. Initially the fish muscle is 
free from bacteria. Fish get contaminated on deck, landing 
centres, processing centres during transportation and storage. 
Bacteria that contaminate fish are mostly of human origin and 
include Esher icha coli 1 Fecal ·streptococci, Coagulase positive 
staphylococci, Salmonella typhi 1 S. paratyphi-i 1 Vibrio cholerae ~· 
etc. Other pathogens that contaminate fish may include 
CJostr idium/botul inumi !Bacillus.: eereu.s, Vibrio parahaemolyticus 1 
Shigella dysenteriae. 8f.ld Listeria monocytogenes, etc. 
E. coli, Fecal streptococci and other coli forms indicate 
fecal contamination. Salmonella contamination make the fish 
unfit for human consumption. These organisms generally do 
not· grow below 0°C. Salmonea is heat sensitive and is destroyed 
at temperature above 60°C. Some detention of frozen sea food 
consignments were done due to salmonella. Presence of V .cho1erae 
have also been detected in sea foods. Crab meat and canned 
product can have C.boty linium tax in, which is quite hazardous. 
Recently Listeria monocytogenes has been detected USFDA 
from prawn and crab meat besides dairy products. This organism 
can survive boiling water temperature from 1-10 minutes and 
causes abortion in human and animals. 
Bacterial contamination can be minimised by observing 
proper care in fish handling and strict hygiene during all the 
stages. Sanitary condition on benches, landing centres and process-
ing units must be improved. Pollution of sea water with untreated 
seawage and effluents must also be prevented. Another problem 
in microbiological analysis is that conventional methods (colony 
counting) take long time~ 
Some rapid methods like spiral plate count, direct epif luores-
cent filter technique (DEFT), enrichment serology and enzyme 
286 BADONIA. RAMACHANDRAN AND SANKAR 
immunoassay have been found to be useful and should be adopted 
in this field. 
PRESENCE OF HEAVY METALS 
Presence of higher concentration of heavy metals like 
mercury, cadmium and copper etc., causeS" serious problems. 
Fortunately higher concentration is mostly in the intesdne 
and in some cases in muscle. Higher quantity of mercury 
in some species of shark and tuna have been reported. Sword 
fish has been- put under automatic detention by USFDA due 
to high mercury in fresh and frozen form. The tolerance limit 
for mercury is 1 ppm. The presence of cadmium upto 300 mg/kg 
was found in the intestine of cuttle fish and squid by the 
authorities of Italian Health Service. The limit for cadmium 
in edible portion is 2 mg/kg. Now the export to Italy is allowed 
after the removal of intestine. The oysters, clams and mussels 
have the tendency to accumulate heavy metals from the polluted 
encirons. The dumping of the untreated industrial waste into 
the sea is the main reason and strict control and moni taring 
is necessary to keep Indian waters free from heavy me tal 
pollutions. 
PROBLEMS IN CURED PRODUCTS 
Quite large quantities of fish is preserved in the form of 
cured products mostly for domestic consumption. Beside traditional 
salted and dried products a new semidried product (Intermediate 
Moisture Product) I.M.P. has become quite popular. This IMP 
has moisture upto 40-50% with good texture and flavour but 
with shorter shelf life of 2-3 months. The main problems in 
this field relate to insect infestation, mites, fungus, presence 
of sand, excess salt, rusting (brown discolouration), pink and 
yellow discolouration etc. These defects lead to the loss of 
quantity and quality of product. The use of 3 ppm sodium 
propionate in salt can improve the quality. Drying. on raised 
platforms,, use of quality salt, avoiding flies, proper packaging 
and fumigation during storage will improve the quality of cured 
products. 
WATER AND ICE QUALITY 
Quality of water and ice used in fish processing is very 
important in maintaining overall quality. The requirement of 
QUALITY PROBLEMS IN FISH PRESERVATION 287 
water to process 1 kg shrimp is 12 litres and 5 litres for fishes. 
The ice requirement is generally 1 : 1. The total plate count 
(TPC) for water and ice should not exceed 100/ml and coliforms 
(MPN) should be less than one 100/ ml, Many times the water 
is not upto this quality and proper chlorination must be done. 
Chemical qualities of water like chloride over 1000 ppm and 
high total hardness also adversely affect the quality of finished 
product. Poor quality water and ice can be potential source 
of secondary contamination. 
CONCLUSION 
For improvement in quality <=;1wareness, training 
and demonstration among fisherman, fish handlers. and others 
associated with trade and industry should be provided. More 
infrastr,uctural faciliUes like ice making b.oth onboard ahfl shore, 
cold storage facilities ana refrigerated tr'ansportation are required. 
the urgent need to update and frame standards for many new 
items in fresh, frozen fish and intermediate moisture products 
(IMP), is felt since long. Balanced induction of machines for 
ice crushing, peeling, grading, etc., will also be helpful. The 
care to protect our seas from poilu tion should be utmost in 
our mind. 


Quality problems in fish processing

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Quality problems in fish processing

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