Oil sardines in prime condition were subjected to onboard chilling. Two lots were chilled in CSW (samples C and CI), a third lot was chilled in crushed ice (sample I) and a fourth lot left not iced on deck (Sample AI). Upon landing sample AI was iced and sample CI was removed from the CSW and iced. All the four samples were kept in a chilled room for storage studies. The fish chilled and stored in CSW recorded the least, and the fish subjected to delayed icing, the highest values for all the indices of spoilage namely, free amino nitrogen, trimethylamine (TMA) and total volatile base nitrogen (TVBN). The total psychrophilic bacterial number also showed a similar trend. The organoleptic assessment of the cooked samples revealed C I, CI, AI to be the order of preference throughout the storage. This assessment was found to hold good for the rest of the parameters as well. The CSW held fishes were found to be distinctly superior to the iced ones for the first five days of storage. Such a marked prevalence in quality for five days would suffice for the fish to fetch a premium in the  market over other landings of the same fish whether chilled or not chilled. Chilling on board in CSW and icing the same after landings, did not show encouraging results

Hiremath, G.G.

Krishnakumar, S.

Menon, N.R.

Shetty, H.P.C.

Aquatic Commons

Sa.rdinella. longiceps in Iced an C HI 
s I ... C anges 
ce 
u 
an us c 
lar 
n s* 
S. KRISHNAKUMAR, G. G. HIREMATH, N. R. MENON** and H. P. C. SHETTY 
University of Agricultural Sciences, College of Fisheries, Mangalore - 575 002 
Oil sardines in prime condition were subjected to onboard chHling; Two lots were 
chilled in CSW (samples C and Cl), a third lot was chilled in crushed ice (sample I) and a 
fourth lot left uniced on deck (Sample AI). Upon landing sample AI was iced and 
sample CI was removed from the CSW and iced. All the four samples were kept in a 
chilled room for storage studies. The fish chilled and stored in CSW rec?rd~d the 
least, and the fish subjected to delayed icing, the highest values for all the m~1ces of 
spoilage namely, free amino nitrogen, trimethylamine (TMA) and total volat1l~ b?-se 
nitrogen (TVBN). The total psychrophilic bacterial number also showed a s1mtlar 
trend. The organoleptic assessment of the cooked samples revealed C I,CI, AI to be 
the order of preference throughout the storage. This assessment was found tc hold 
good for the rest of the parameters as well. The CSW held fishes were found to be 
distinctly superior to the iced ones for the first five days of storage. Su?h a ~arked pre-
valence in quality for five days would suffice for the fish to fetch a premmm m t~e_ mar-
ket over other landings of the same fish whether chilled or unchilled .. _Chilhngon-
board in CSW and icing the same after landings, did not show encouragmg results. 
· Unlike refrigerated seawater (RSW) 
there is limited literature avajlable on 
chilled seawater (CSW) as a mode of pre-
servation. The potency of CSW. in chill-
ing and preserving freshly caught :fish was 
known as early as 1931. The view that a 
quicker and more effective temperature 
reduction, brought about through RSW/ 
CSW chilling, retards bacterial action there-
by enhancing the she1f-1if e has been exten-
sively supported (Roach et al. 1961; Spen-
cer & Baines, 1964 and Shewan, 1965). 
The effects of RSW/CSW holding on the 
keeping quality -0f temperate species (de-
mersal/pelagic) have been studied in detail. 
However, data on tropfoa1 species is limi-
ted. Information on the pattern of spoilage 
of oil sardine, during CSW holding, is 
lacking and the present paper reports the 
attempt of the authors on ice and CSW 
preservation of oil sardines. 
*Formed part of the M.F.Sc. Thesis (University of 
Agricultural Sciences, Bangalore) of the first author. 
'!'*Present address: School of Marine Sciences, Uni-
versity of Cochin, Cochin-682 016 
Mate.rfals and Methods 
Live oil sardines were procured from the 
net of a purse seiner operating off Manga-
lore. The CSW medium was prepared by 
mixing one part of seawater (of 3.4%
0 
salinity) with 2.5 parts of crushed ice. 
Insulated, galvanised MPEDA fish boxes 
were used for storing the samples. The 
.raw material was divided into four Jots of 
35 kg each. Two lots were chilled in CSW 
in the fish boxes, the ratio of fish to csw 
being 1: l by we1ght. A third lot was pre-
served in ice, in a fish box. To simulate 
purse seine fish liandling practices, a fourth 
lot was heaped on deck, exposed to sun and 
wind, transported in bamboo baskets to 
the laboratory, iced and stored in a fish 
box (4 h after capture). AU the four sam-
ples were p1ced inside a chilled storage 
(1 ± 1 °C) for further storage studies. 
The samples were subjected to treatment as 
follows: 
1. Sample C, chilled in CSW onboard, 
was further stored as such. 
FISHERY TECHNOLOGY 
PRESERVATION OF SARDINES IN ICE AND CHILLED SEAWATER 127 
2. Sample CI, also chilled in CSW on-
board, was removed from the medium 
and iced. 
3. Sample I, iced onboard, was drained 
of meltwater and replenished with 
fresh ice. 
4. Sample AI, held uniced onboard, was 
iced. 
Icing was done in a.lternate layers of fish 
and ice, in the ratio 1 : 1 by weight. Daily 
melting of ice was compensated for with 
fresh ice. 
A daily assessment of the rate of belly 
bursting was made. One hundred fish 
were randomly picked from each sample 
and the percent belly burst determined each 
day. Moisture, protejn nitrogen, non-
protein nitrogen, crude fat and ash content 
in the fish samples were determined by the 
methods described by AOAC (1970). 
Free amino nitrogen was determined by 
the method of Pope & Stevens (1939). 
The colorimetric method of AOAC (1975) 
was followed for trimethylamine (TMA) 
in the muscle. Total volatile base nitrogen 
(TVBN) was determined by Conways' micro-
diffusion method as described by Beatty & 
Gibbons (1937). 
Ten grams of skin and flesh were homo-
genised with 90 ml saline. Serial dilutions 
were made and plated i.n duplicate on nut-
rient agar (fortified with 3% sodium chlo-
ride) by spread plate. The psychrophilic 
bacterial count was determined after in-
cubation at 20°C. 
Representative samples from aH the 
treatments were dressed, deaned and stea-
med for 10 min and then presented to a 
panel of fifteen trained judges. Attributes 
of quality such as appearance, flavour, 
odour and texture were judged on the basis 
of a ten point hedonic scale. The judge-
ment of the panel was valued and average 
scores taken. Data of the . organoleptic 
assessment was subjected to statistical ana-
lysis. 
Results 
The average values of moisutre, protein, 
fat and ash of the fish samples are presented 
VoL 22, 1985 
in Table · l. A gradual decrease in total 
nitrogen was observed for an the samples 
over the storage period. While sample I 
Table 1. Proximate composition of sardine 
muscles (as per cent of meat) 
Moisture Protein Fat Ash 
68.36 19.00 10.30 1.94 
exhibited the m1mmum decrease, sample 
AI recorded the maximum (Table 2). The 
non-protein nitrogen as a percentage of total 
nitrogen exhibited an increasing trend, 
There was no noticeable difference between 
treatments. Free amino nitrogen values 
also recorded an increasing trend. Sample 
C recorded the least increase (Fig. 1 ). The 
total volatile base nitrogen found to increase 
4 o---<> Sample C 
o-·--o Sample· I 
e- - - ... Sample CJ 
........... .., Sample AI 
200 2 3 4 5 6 7 8 9 
Storage penod (Days) 
Fig. 1. Changes in free amino nitrogen content 
of sardine muscle during chilled storage. 
steadily. Sample C showing the least in-
crease and sample AI the highest (Fig.2). 
It is of foterest to note here that sample 
CI recorded a higher rate of increase· of 
TVBN towards the fatter half of the storage 
~ 830 
::::: 
0
-----" Sample C 
o- --<> Sample I 
,._ - - --0 Sample CI 
"····· · ., Sc;mple Al 
o······ ...... . 
•.•.. $' 
... ··· 
120 ..... -·········_,,.,., 
z 
co 
>I 
I-
23456~ 
Sroroga period !Ocys l 
Fig. 2. Changes in volatile base nitrogen content 
:in sardine muscle during chilled storage. 
128 S. KRISHNAKUMAR, G.G.HIREMATH AND N.R.MENON 
Table 2. Change in nitrogenous constituents of sardine muscle during chilled storage in ice and 
csw 
Total nitrogen (g/100 g meat) 
C CI I AI 
3.38 
3.35 
3.30 
3.19 
3.09 
3.38 
3.32 
3.28 
3.15 
3.02 
3.39 
3.35 
3.29 
3.20 
3.12 
3.35 
3.29 
3.20 
3.09 
2.98 
penod. Similar trends were noticed in 
trimethyfamine (Fig.3) as well as total plate 
Storage period {Days J 
Fig. 3. Changes in trimethylamine content in sardine 
muscle during chilled storage. 
count of psychrophilic bacteria (Fig. 4). 
The TMA values did not exceed 10% 
mg in any of the samples. Bacterial count 
exhibited an approximate three-fold 
.mcrease. 
}0 
0 2 3 4 5 6 7 6 9 
Storage period (Days) 
Fig. 4. Changes in bacterial load during chilled 
storage of oil sardine. 
Sardine held in CSW showed a relatively 
very low belly burst percentage upto the 
fifth day (11%), while samples, CI, I and 
AI recorded values over 20% (Table 3). 
By the ninth day while sample AI had 81 % 
fish with torn bellies, the value was as low 
as 55% for the CSW held sardine (sample C). 
Storage NPN (as per cent TN) 
period c CI I AI 
(days) 
0 
2 
5 
7 
9 
9.88 9.88 9.99 10.12 
9.85 9.98 9.90 10.18 
10.12 10.18 10.08 10.33 
10.33 10.43 10.33 10.78 
10.58 10.74 10.69 11.09 
Table 3. Percentage belly burst during 
chilled-storage of sardine in ice 
and CSW 
Storage 
period, Samples 
days c CI I AI 
0 0 0 0 4 
l 0 0 0 8 
2 2 10 4 16 
3 3 15 8 20 
4 5 19 15 26 
5 11 24 20 34 
6 24 39 34 52 
7 34 40 42 63 
8 46 60 51 70 
9 55 70 60 81 
The appearance, odour, -flavour and tex-
ture of sample AI became unacceptable 
after the fifth day, and those of samples 
CI and I after the seventh day. Sample 
C remained acceptable in terms of texture 
APPEARANCE 
DC OCI 01 0 Al 
0 
9 -
E -
"' ~ 7 0 I-
~ 6 
g! 5 0 
a. 4 - - - - L.- - -I- - - ... - ... - -
c ~ 
0 3 
"' ;;: 
2 
I 
2 3 4 5 67 fl9 
Storage period (Days) 
Fig. 5. Acceptability scores (appearance) for cooked 
oil sardine during chilled storage. (Excellent < 10; 
Good < 8; Fair :=;;;: 6; Borderline = 4; Bad > 
2; Putrified > 0 
FISHERY TECHNOLOGY 
PRESERVATION OF SARDINES IN ICE AND CHILLED SEAWATER 129 
Table 5. Analysis of variance for mean panel scores for samples in various treatments 
Sources of Degrees of 
variation freedom 
Between attributes 3 
Between samples 3 
Between days 4 
Interaction between 9 
attributes and samples 
Interaction between 12 
samples and days 
Interaction between 12 
Attributes & days 
Error 36 
Total 79 
*Significant at 5% level 
ODOUR 
0 C 0 CI Cl I 0 AI 
0 
9 -
"' 8 Q) 
0 7 
0 -
"' 6 a; 
§5 
a. 
c4 _,__ ~--- .-1--
0 
~3 
2 
.r 
2 3 45 67 89 
Storage period (Days) 
Fig. 6. Acceptability scores (odour) for cocked oil 
sardine during chilled storage (Excellent < 10; 
Good S 8; Fair :S: 6; Borderline= 4; Bad~ 2; 
Putrified > 0) 
FLAVOUR 
0 C 0 Cl DI 0 Al 
10 
9 
-8 
-
-T- -~7 -§6 -
-
.. 
a; 5 
c g_ 4 - ~ - - -1- - - _,_ - -- ,,.. -- -
-§3 
"' 1 ~2 I 
2 3 4 5 6 7 8 9 
Storage period (Days) 
Fig. 7. Acceptability scores (flavour) for cooked oil 
sardine during chilled storage. (Excellent < 1 O; 
Good< 8; Fair~ 6; Borderline = 4; Bad22 
Putrified > 0) 
VoL 22, 1985 
Sum of Mean sum F-ratio 
squares Oi. squares 
0.327 0.1090 3.2812* 
54.973 18.3243 55L6045* 
364.190 91.0475 2740.7435* 
1.324 0.1471 4.4281 * 
19.787 1.6489 49.6358* 
1.083 0.0903 2.7182* 
1.196 0.03-32 
442.880 5.6061 
and appearance for the ninth day also. 
However, the average odour and flavour 
scores of sample C had declined to the 
border line of acceptability by the ninth 
day (Figs. 5, 6, 7 & 8). Analysis of variance 
of the mean panel scores (Table 4) showed 
significant differences due to samples, attri-
butes, and days and also between their 
interaction. The highest significance was 
TEXTURE 
De OCI Di O·A; 
- -
-
-
-
-
-
-
---
-- --
-- - ;::. -
I 
2 3 4 5 . 6 7 .8 9 
Storage periad !Days) 
Fig. 8. Acceptability scores (texture) for cooked 
oil sardine during chilled storage (Excellent < 10; 
Good < 8; Fiar :::;:: 6; Borderline = 4; Bad-> 2; 
Putrifiect :2:: 0) -
due to days followed by samples and attni-
butes. The highest interaction was noticed 
between samples and days followed by 
attributes and samples. 
Discussion 
The marginal decrease in total nitrogen 
and the increase in non-protein nitrogen 
130 S. KRISHNAKUMAR, G. G. HIREMATH AND N. R. MENON 
(Table 2) after an initial marginal recuction 
can be attributed to proteolysis and bacte-
rial action. A similar trend in total nitro-
gen was observed for sardines held in ice 
(Shenoy & Pillai, 1971). The free amino 
nitrogen did not show an initial decline as 
reported earlier (Govindan, 1971). How-
ever, the increase in free amino nitrogen 
for the first :five days was marginal. Beyond 
the fifth day the rate of increase was no-
ticeably high, though not prnnounced (Fig. 
1 ). Leaching losses could have played a 
significant role in masking the actual rate 
of production of free amino acids. In-
crease in free amino acid content towards 
the later stages of storage can be linked 
with bacterial proteolytic action (Shewan, 
1961). 
Volatile bases increased ~apidly in 
samples AI and CI. This mcrease in 
TVBN for sample AI can be attributed to 
its exposure to a high ambient tempera-
ture before it was iced. This is further 
supported by a very high zero day value for 
samples AI as compared to the other three 
samples (Fig. 2). Holding temperature 
had a direct impact on the TVBN produc-
tion in fish (Hansen et al. 1974). The 
levels of volatile bases recorded for sample 
C throughout the study establishes the 
superiority of CSW as mode of preserva-
tion. Results obtained by Hiremath et al. 
(1980) do corroborate this. A similar 
pattern was established for the trimethyla-
mine values of the four samples. While 
TMA increased rapidly in samples CI and 
AI, the rate of increase m samples I and C 
remamed relatively low, sample C recording 
the least increase (Fig. 3). Although spoi-
lage was sensorily evident by the 5th, 7th 
and 9th days for samples AI, CI and I res-
pectively, the TMA values for no sample 
exceeded 10 mg% . 
Increase in the TMA values can have a 
direct bearing on the viable count of bacte-
ria (Tarr, 1938). An increase in the viable 
count of the bacteria during the present 
study correlates well with the increase in 
TMA. Holding sardines in CSW and ice 
for nine days resulted in an approximate 
three fold increase in their bacterial load 
(Fig. 4). Similar results were obtained 
during holding of sardines in RSW for six 
days (Perigreen et al., 1975). During the 
present study sardines subjected to delayed 
icing showed much higher bacterial load. 
Upto the fourth day bacterial count for 
CSW held sardines was significantly lower 
than that of iced ones. This can be attri-
buted to a faster rate of chilling and a lower 
temperature of storage obtained in CSW 
(Spencer & Baines, 1964) and also due to 
the anaerobic environment in CSW, inhi-
biting the growth of obligate aerobes 
(Shewan, 1965). However, beyond the 
fifth day the bacterial load of the CSW held 
sardine parallels that of the iced one (sample 
I). This may be due to the microflora 
released from the gut of the CSW held 
sardines, as noticed by a peak in the belly 
burst rate after five days. Relatively higher 
bacterial load for samples CI and AI may 
also be attributed to higher belly damage 
rates observed during the same period. 
Holding fish in CSW or RSW has the 
distinct advantages of preventing undue 
pressures on the fish, thereby eliminating 
any physical damage (Eddie & Hopper, 
1974). RSW was found to be a better 
medium in reducing physical damage as 
compared to ice (Perigreen et al., 1975). 
However, very low belly burst rates obser-
ved during the present study (Table 3) as 
compared to values obtained elsewhere, 
may be owing to the fact that chilling of 
the catch was done within 15 min of cap-
ture. Thus there is an emphasis on the 
importance of immediate and rapid onboard 
chilling. 
Analysis of variance for the mean panel 
scores of the cooked samples (Table 4) 
showed significant differences for samples, 
days, attributes and their interactions. 
The results of organoleptic analysis of cooked 
samples (Figs. 5, 6, 7 and 8) reveal that 
immediate chilling by CSW definitely im-
prove the shelf-life of the fish by atleast 
4 to 5 days. The CSW held sardine (sample 
C) showed a shelf-life of 9 days as compared 
to 7 days for sample I. Sample C was 
found to be noticeably superior in appear-
ance and texture based on sensory evalua-
tion 
Compared to sample AI, sample CI ex-
hibited lower values of total psychrophilic 
bacterial count, TVBN and TMA during 
the first 6 days of the experimental period. 
FISHERY TECHNOLOGY 
PRESERVATION OF SARDINES IN ICE AND CHILLED SEAWATER 131 
However, towards the latter half of the 
experiment, the rate of increase of the 
three parameters in sample CI was signi-
ficantly higher as compared to the other 3 
samples. The fact that sample CI was 
handled excessively due to the re-icing pro-
cess could have contributed towards a 
higher contamination of the fish with the 
putre1active types of bacteria. 
Onboard chilling of fatty species, like 
sardine in CSW enhances the shelf-life of 
the fish by 2 to 4 days. The quality of 
CSW held fish during the first 5 days of 
storage, was distinctly superior to the iced 
samples, including the onboard iced sam-
ple. Although there were no distinct ad-
vantages beyond the fifth day, for CSW 
over ice, it is of little significance to fresh 
fish preservation since the :fish is consumed -
processed, retailed or reduced - within a 
day or two of capture. Hence it may be 
of interest to note here that a five day life 
in prime. condition provides ample time 
to transport the fish to even distant markets 
for retailing, thereby creating the possibi-
lity of wider markets and premiums on the 
sale price. 
References 
AOAC (1970) Official Methods of Analysis, 
11th edn. Association of Official Agri-
cultural Chemists, Washington, D.C. 
AOAC (1975) Official Methods of Analysis, 
12th edn. Association of Official Agri-
cultural Chemists, Washington, D.C. 
Beatty, S.A. & Gibbons, N.E. (1937) J. 
Biol. Bd Canada. 3, 77 
Vol. 22, 1985 
Eddie, G.C. & Hopper, A.G. (1974) Fishery 
Products, (Kreuzer, R. Ed.), p. 69, 
Fishing News (Books) Ltd., England 
Govindan, T.K. (1971) Indian Fd Packer 25,27 
Hansen, P., Olson, K.B. & Peterson, T.E. 
(1974) Fishery Products, (Kreuzer, R. 
Ed.) p. 64, Fishing News (Books) Ltd., 
England 
Hiremath, G.G., Teutscher, P. & Nordheium, 
A. (1980) FAO Technical Report, FAO-
DANIDA Workshop on Handling of 
Small Fish in the Arabian Sea, Manga-
lore, India 
Perigreen, P.A., Pillai, A.S., Surendran, 
P.K. & Govindan, T.K. (1975) Fish. 
Tec!mol. 12, 105 
Pope, C.G. & Stevens, M.F. (1939) Bio-
chem. J. 33, 1070 
Roach, S.W~, Harrison, J.S.M. & Tarr, 
H.L.A. (1961) Bull. Fish. Res. Bd. 
Canada, 126 
Shenoy, A.V. & Pillai, V.K. (1971) Fish. 
Technol. 8, 37 
Shewan, J.M. (1961) Fish as Food, Vol. 1. 
(Borgstrom, G Ed.), p. 484, A~:oi<lemic 
Press New York 
Shewan, J.M. (1965) Fish Handling and Pre-
servation, p. 95 O.E.C.D., Paris 
Spencer, R. & Baines, C.R. (1964) Fd. Te-
chnol. 18, 175 
Tarr, H.L.A. (1938) Nature. 142, 1078 


Preservation of Sardinella longiceps in iced and chilled seawater. Part 1 - Changes during storage with particular reference to bacterial load and nitrogenous compounds

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Preservation of Sardinella longiceps in iced and chilled seawater. Part 1 - Changes during storage with particular reference to bacterial load and nitrogenous compounds

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