Technological aspects of preservation and processing of edible shell fishes III. Factors influencing the keeping quality of crab (Scylla serrata) during freezing and frozen storage

The possible factors leading to the loss of flavour and general quality of crab during freezing and frozen storage have been studied. The preprocess ice storage condition of the raw material was found to be one such important factor while the fresh frozen crab meat remained in good organoleptic condition for about 51 weeks at -23°C, the 7 days iced material held frozen was found to have a shelf life of about 21 weeks. The fall in myofibrillar protein noted during frozen storage together with the loss of myosin ATPase activity correlated well with the loss of organoleptic qualities.

Bacterial aspects of quality of phosphate treated frozen prawns

Changes in physical, organoleptic and biochemical characteristics of phosphate treated prawns and frog legs during storage have been studied in detail by Mathen and Pillai, (1970). Adoption of the recommended method by the industry in the freezing of prawns made it necessary to assess the influence of such treatment on the bacterial quality. This aspect assumes more importance in view of the proposed compulsory bacterial standards for raw frozen prawns. This note gives an account of the results on the influence of phosphate treatment on bacterial quality of raw frozen shrimp meat.

A survey on the quality of Indian fish meal of commerce

Data on proximate composition, total volatile bases, total non-protein nitrogen and bacterial quality of commercial samples of Indian fish meal are presented in this communication. The samples vary very much in quality depending on the type of raw material used and method of processing followed. The data are discussed in relation to the Indian standard Specifications for fish meal as livestock feed.

Oxidation of residual lipids in fish protein concentrates and its effect on the nutritional quality of the protein

The paper reviews the work reported on the changes in the nutritive value of fish protein concentrates (FPC) during, storage, with special emphasis on the effects of the interactions between oxidised residual lipids and proteins of the FPC. Theories on the oxidised lipid-protein interactions are reviewed and the nutritional significance of these reactions is discussed.

Microbiological evaluation and keeping quality of fishes reared in livestock sewage fed ponds without artificial feed

Livestock sewage has been utilized for fish culture. There is lack of information on microbiological evaluation and keeping quality of these fishes. This paper reveals the incidence, types of micro-organisms and keeping quality of fishes reared in livestock sewage fed ponds without artificial feed. These fishes revealed microbial incidence and keeping quality comparable to other fishes. Initial mesophilic and psychrophilic counts varied from 3.38 to 5.56 and 2.47 to 4.74. On an average, the counts reduced by about 40% after evisceration and washing. Whole as well as washed fishes had refrigerated (8 ± 1°C) life of not more than 4 days. The average psychrophilic and mesophilic counts of ice (0 to 1°C) stored whole fishes up to 10th day varied from 3.66 to 4.81, 4.61 to 5.24 and in eviscerated and washed fishes 2.17 to 3.69 and 2.78 to 4.41. Both remained acceptable till the 10th day. Qualitative study of surface slime and gills revealed presence of Aerobacter (Enterobacter), Aeromonas, Alcaligenes, Bacillus, Clostridia, E. coli, Klebsiella, Micrococci, Proteus and Pseudomonas.

Influence of muscle fats on the quality of intermediate moisture fish

Chrysicthys nigrodigitatus with 12.95% fat having an iodine value of 74.8 and a saponification number of 198.48 and Citharinus citherus containing only 3.25% fat with iodine value of 67.8 and a saponification number of 145.86 were studied as examples of fatty and lean fishes respectively. The intermediate moisture (IM) products of both fish types compared with normal cooked samples, were evaluated as of acceptable colour, odour, texure and juiciness but of inferior taste due to the glycerol impact. However, during storage at 30°C the IM products became increasingly less acceptable with the deterioration being greater in the fatty fish than in the lean fish, although the fatty IM fish was superior to the IM lean fish with regard to water retention and juiciness. Overall quality differences were most apparent in colour and odour with the fatty IM fish being worse. The fatty fish had also greater evolution of TEA-reactive carbonyl breakdown products of lipid oxidation which were subsequently used up in non-enzymic browning producing the correspondingly darker fish colour and greater off odour.

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.

Formulation, stability and keeping quality of three pelleted feeds used in carp culture

Three dry pelleted feeds incorporating fish meal, fish silage or a mixture of colocasia leaf powder and fish meal were formulated for use in carp culture. The diets formulated were tested for water stability and also for changes in their quality parameters over storage of three months. The different pellets showed satisfactory water stability. The variations recorded in the proximate composition during the period of storage did not bring about any drastic change in the overall keeping quality of the feeds. Therefore, the three formulated feeds are considered suitable for use in the culture of carps.

Study on the quality of beche-de-mer in trade and shrinkage of specimens during processing

The beche-de-mer industry in India is a cent percent export oriented industry being confined to south east coast in Palk Bay and Gulf of Mannar in Tamil Nadu. Chemical quality of 180 trade samples of beche-de-mer of four sizes collected from the beche-de-mer curing centres of Ramanathapuram district was studied. Moisture ranged from 6.2 to 24.4% and sand content from 0.11 to 20.42% for all grades. Mean values of sand content are for grade 1=3.47%, grade 2=4.50%, grade 3=3.68%, grade 4=6.87%. Sodium chloride was almost constant for all grades at 5.7%. TVBN values ranged from 10 to 78.4 mg%. 44 laboratory samples of different grades were prepared following trade practice and examined for chemical quality. Mean moisture values are for grade 1=13.4%, grade 2=12.44%, grade 3=12.62%, grade 4=12.08% and mean values of sand are for grade 1=0.70%, grade 2=0.90%, grade 3=1.16%, grade 4=2.15%. The percentage of shrinkage of the animals ranged from 56% to 60% for dried beche-de-mer of 7.5 cm size and above.

Assessment of quality of fish landed at the Cochin fisheries harbour

Assessment of quality of fish and shrimps landed at the fish harbour, Cochin, was made over the period January, 1980 to December, 1982. A total of 201 samples were analysed. Nearly 75% of the samples scored between 6-10 in a 10 point hedonic scale and the percentage unacceptability based on sensory assessment was 5. 5%. In 10.1% of the samples, total volatile nitrogen was >30 mg% and in 8.3% of the samples trimethylamine- nitrogen was >10 mg%. Both, the gr Torrymeter and Intellectron Fish Tester VI readings marked significant correlation with sensory scores and chemical indices; but failed to bear any significant correlation with bacterial counts. Of the 5-1 total samples 66.7% had total plate count (TPC) ≥10 super(5) g super(-1) and 8.5% were considered unacceptable based on TPC >5x10 super(5) g super(-1); 63.2% of the samples were free from Escherichia coli; 26.4% had >20 E. coli g super(-1) and 20.4% of the samples contained faecal streptococci >10 super(3) g super(-1). Seven percent of the samples showed coagulase positive staphylococci >100 g super(-1). Salmonella could not be detected in any of the samples examined. Crushed ice samples and the platform of the harbour had high bacterial loads.

Effect of oxidation of dietary fish lipids on the quality of proteins in diet

The paper reports results of a study on the effect of oxidised fish oil in the diet on the quality of dietary fish proteins. With increased oxidation of oil, digestibility and utilization of the protein registered a decrease. Oxidation of fish oil beyond a stage was found to affect the intake of diet itself and rats lost weight rapidly.

Studies on the effect of leaching on the quality of ice-stored fish

A comparative ice storage study of milk fish (Chanos chanos) in direct contact and out of contact (in 200 gauge polyethylene bag) with ice was taken up to assess the effect of leaching on quality of ice-stored fish. It was observed that the leaching effect was more significant on TVN and NPN than that on cc amino nitrogen components while there was very little effect on bacterial load. It is concluded that under similar conditions of icing, fish out of contact with ice will have longer shelf life and more acceptability than the fish preserved in contact with ice.

The effect of washing on the quality of minced catfish during frozen storage

The effect of washing minced catfish in water, sodium chloride solution (1%) and ascorbic acid solution (0.1%) in improving the quality and frozen shelf-life has been studied. Washing improved the colour and reduced the non-protein nitrogen contents and extractable nitrogen. Denaturation was more in samples washed in salt and ascorbic acid solutions. Rancidity as measured by PV and organoleptic studies showed significant reduction in washed samples. The frozen storage life was significantly enhanced by washing.

Quality of fish preparation served in catering establishments of Bombay

The results of the study carried out on the quality of fish preparations served in catering establishments of Bombay revealed that there is no serious potential health hazard to the consumer. Pathogens like Salmonella and Clostridium per were found to be absent. Based on organoleptic, biochemical and bacteriological parameters the quality of fish curry was better than that of fish fry. Overall quality of samples from grade I establishments was better in comparison with grade II and III. However, a few samples of poor quality were also observed in grade I. Extraneous matter like hair and dead housefly were observed in a few samples from grade III indicating poor handling practices. The importance of good hygiene and sanitary practices in catering establishments is discussed.

Quality of cured fish from Tamil Nadu coast

Results of studies of chemical, bacteriological and organoleptic quality of cured fish collected from four major curing centres along the Tamil Nadu coast are reported. Only 32.43% of the samples had moisture level below 35%, 0.9% had salt 25% and above. None of the samples showed acid insoluble ash below 1.5%. The main defects were unhygienic processing, inadequate salting, use of poor quality salt and incomplete drying. Recommendations for improvement of quality are given.