Methods of sensory evaluation of quality and application of statistical methods in sensory evaluation problems with special reference to fishery products

The quality of raw and processed fishery products depend on several factors like physiological conditions at the time of capture, morphological differences, rigor mortis, species, rate of icing and subsequent storage conditions. Sensory evaluation is still the most reliable method for evaluation of the freshness of raw processed fishery products. Sophisticated methods like Intelectron fish tester, cell fragility technique and chemical and bacteriological methods like estimation of trimethylamine, hypoxanthine, carbonyl compounds, volatile acid and total bacterial count have no doubt been developed for accessing the spoilage in fish products.

Freeze drying of fishery products: Part IV - Biochemical changes occurring in prawn muscle during freezing, freeze drying and prolonged storage of the freeze dried product

The changes occurring in water and salt extractable protein and non-protein fractions in prawn muscle of different species during freezing, freeze drying and subsequent prolonged storage have been studied. There is no denaturation of water extractable proteins, whereas salt extractable proteins were rendered insoluble to the extent of 21% due to freeze drying. The freeze dried products remained in good edible condition for 32 months of storage up to which storage characteristics were followed.

Freeze drying of fishery products: Part V - Storage characteristics of ready-to-serve freeze dried foods

Behaviour of freeze dried ready-to-serve fish based food preparations during prolonged storage at room temp has been studied and reported in this paper. Storage life of such products under the conditions employed in this study can be reckoned in years at our ambient temps.

The influence of plating technique and incubation temperature on bacterial count from fish and fishery products

For bacterial sampling of raw unprocessed fish and frozen fishery products, spread plate method is preferable to pour plate method; incubation of plates at 30°C gives a higher count than incubation at 37°C. Analysis of variance of the data shows that sample variation between different types of fishes is highly significant whereas the variations between triplicate plates are not significant at 5 % level.

Ecology of Indian estuaries-XI. A preliminary survey of the fishery resources of the Ashtamudi estuarine system

The fish fauna of the Ashtamudi, the second largest estuarine system in Kerala (8°53'-9°02' N Lat. and 76°31'-76°41' E Long.) is listed. 97 species belonging to 39 families have been recorded, ofwhich69 are commercially important contributing to the fisheries of the Ashtamudi Estuary. Mullets, cichlids and the glassy perchlets are the most abundant groups and contribute appreciably to the landings. Results revealed that the estuarine system supports a good capture fishery which is seasonal. Majority of the fish fauna in the estuary are marine elements recruited from the adjoining Arabian Sea. An inventory of the craft and gear employed is presented and the sources of pollution in the estuarine system are described, aquacultural prospects of this area are discussed.

Quality of cured fishery products from Malabar and Kanara coasts

Results of chemical, bacteriological and organoleptic quality studies of cured fishery products of commerce collected from six major fish curing centres on the west coast of India are presented. 77.12% of the samples had moisture above 35%, 97.18% showed salt content below 25% and all samples had acid insoluble ash above 1.5%. 42.32% gave standard plate counts above 10,000 and 45.77% were contaminated with 'Red' halophiles. The major defects in curing were imperfect cleaning, inadequate salting and unhygienic conditions of processing.

Selection of suitable diluents for bacteriological examination of fishery products

For raw, iced and frozen samples of fish and prawn, significant difference was observed in total plate counts done with various diluents, the significance level ranging from 5% to 0.1%. For raw fish, N-saline, seawater and quarter strength Ringers' solution gave maximum total plate counts. In the case of iced-fish, n-saline yielded highest total plate counts. For frozen samples, however, peptone water and n-saline gave good recoveries. Trials with suitable combinations of diluents showed that though some of them were as good as the control, namely n-saline, none were superior in any way.

Antibiotic sensitivity of Staphylococcus aureus strains isolated from fishery products

During the course of an investigation on the incidence of Staphylococcus aureus contamination in frozen crab meat, frozen prawns and dried fishes from Cochin, 116 strains of S. aureus were isolated. The sensitivity of the isolated strains towards nine antibiotics showed that all the S. aureus strains were sensitive to kanamycin and streptomycin (100%). Sensitivity to other antibiotics like chloramphenicol, polymyxin-B, erythromycin, tetracycline, neomycin, penicillin and ampicillin were shown by 98.28, 93.10, 87.93, 68.10, 67.24, 56.90 and 55.17 percent of the isolates respectively.

Dol net fishery off Nawabunder (Gujarat)

Extimated catch of 6,484.9; 3,505.6 and 4,797.7 t of fishes were landed at Nawabunder in 'dol.' net during 1976-77, 1977-78 and 1978-1979 respectively. There has been an increasing trend in effort and decline in catch and catch rate. The catch rate came down from 174.8 kg in 1976-77 to 84 kg in 1978-79. The detailed studies on the catch composition revealed that the Bombay duck formed about 68.6-77% of the total catch. The other important constituents being Coilia dussumieri 1.5-9.2%, ribbon fish 3.0-6.5%, non-penaeid prawn, namely, Acetus indicus, Nematopalaemon tenuipes and Hippolysmata ensirostris together formed about 6.1-13.7% and penaied prawns 1.5-3.1% of the total dol net landings. In addition, quality fishes such as ghol, warn, pomfret and catfishes were also landed in considerable quantities. The landings of ghol are on the increase from 4.9 t in 1976-77 to 59 t in 1978-79. Large number of juveniles of economically important fishes namely, Harpodon nehereus, Pampus argenteus, Trichiurus lepturus and Ilisha filigera have been observed in the catch particularly during February-May. The destructive nature of the gear has been commented along with the suggestions for regulation of the fishery.

Occurrence of enterotoxigenic staphylococci in frozen fishery products

Sixty six samples of frozen fishery products consisting of frozen crab meat, frozen prawns, frozen cuttlefish and frozen mussel collected from nine cold stores situated in and around Cochin city were examined for coagulase positive staphylococci. Forty eight samples (72.72%) revealed the presence of coagulase positive staphylococci, which were then tested for enterotoxigenity, employing cellophane-over-agar method for toxin production and optimum-sensitivity-plate (OSP) method for toxin detection. Seventy seven out of one hundred and two (75.49%) coagulase positive staphylococcal isolates from the above products produced enterotoxins A, B, C, D and E either singly or in combinations. Enterotoxin A and D were detected more often than others. The occurrence of enterotoxigenic staphylococci in frozen fishery product is reported for the first time in this country.

Stock assessment of the demersal offshore fishery resources off the Karnataka coast

The total biomass of the demersal stocks in the depth range of 30-200m between 12°401 and 15°N latitudes in the Indian Exclusive Economic Zone is estimated to be a:round 1,23,000 metric tons (t). There is scope for doubling the present catch of about 40,000 t from demersal resources by extending exploitation to 50-200m depth zone. About 78% of this increase is expected to come from four species, namely, Nemipterus japonicus, Priacanthus macracanthus, Saurida tumbil and Arius spp.

Incidence and low temperature survival of coagulase positive staphylococci in fishery products

Coagulase-positive staphylococci was found to be absent in all the frozen samples of lobsters, cuttle fish, cat fish, seer fish and red snapper examined. Coagulase-positive staphylococci were present in 38% of the cooked frozen shrimps and only 16% of the samples had staphylococci count more than 100/g. In the case of headless, peeled and deveined, peeled undeveined shrimps, the incidence of the organism was 6, 12 and 16% respectively. The study indicated that the incidence of coagulase-positive staphylococci is not a serious problem in frozen fishery products processed in this country. There was remarkable difference in the rate of destruction of coagulase-positive staphylococci in raw and cooked shrimps during freezing and frozen storage.

Fishery of mud crab, Scylla serrata (Forskal) from Karwar waters

Catch data of Scylla serrata obtained in different gears from Karwar region during December 1983 — November 1984 indicated a sum of 9608 kg of landings of crabs. Majority of the crabs (89.57%) was found to be caught in backwaters by line fishing and cast nets. A considerable (10.43%) quantity of catch was also contributed by gill nets and shore-seines from inshore waters. A maximum of 1207 kg of crabs were landed in December, 1983. The size structure and sex-ratio of S. serrata varied with gear type and period.

Incidence and low temperature survival of Salmonella in fishery products

Salmonella was isolated from 12% of PD shrimps, 10% of HL shrimps, 14% of PUD shrimps, 17% of lobsters, 14% of cuttle fish, 25% of cat fish and 20% of seer fish (all frozen) tested. One percent of the fish meal, 4% of dried non-penaeid prawn and 23% of sea beach sand showed incidence of the organism. Salmonella was also isolated from 2 and 4% of the swab samples of utensil surfaces and the floor surface of the processing hall respectively as well as from 1% of the process water tested. All the serotypes of Salmonella tested were resistant to freezing at -40°C, but during subsequent storage at -20°C, there was some difference between the serotypes with regard to their viability, S. paratyphi B being the most resistant which survived up to 9 months while S. saintpaul the least resistant having survival up to 5 months only.

On the pattern of Salmonella serotypes in fishery products, froglegs and processing environments

Thirty four different serotypes of Salmonella have been isolated from aquatic products. The number of serotypes from frozen froglegs were 22. Only four serotypes were isolated from frozen shrimps. S. weltevreden predominates in frozen shrimps and fish. S. roan and S. larochelle were isolated for the first time in India. Isolation of six rare serotypes of Salmonella has also been reported.