On the measurement of concentration of blanching brine by electrical conductivity method

Blanching is an important operation in the shrimp canning process, in order to bring down the moisture content of the product to the required level, to allow the proteins to coagulate and to give proper texture, shape and characteristic pink colour to the meat. It has been observed that among other factors responsible for fluctuations in the drained weight in the canned prawns, concentration of brine used for blanching and the duration of blanching are important (Varma, Chaudhury and Pillai 1961). The papers gives details of experiments

Acute toxicity of cadmium to six intertidal invertebrates

Following a static bioassay techniques the acute toxicity of cadmium to six species of intertidal invertebrates was determined. The sensitivity of the animals to cadmium was of the following order: Emerita sp. (burrowing crustacean) Donax spiculum (burrowing bivalve) Perna viridis (sedentary bivalve) Sabellaria clandestinus (tube-dwelling polychaete) Modiolus carvalhoi and Modiolus sp. (sedentary bivalves). The above observation was based on the median lethal concentrations recorded for the different species, Emerita sp. 1.35 p.p.m., Donax spiculum 1.8 p.p.m., Perna viridis 2.5 p.p.m., Sabellaria clandestinus 2.8 p.p.m., Modiolus carvalhoi 5.6 p.p.m. and Modiolus sp. 9.6 p.p.m. The findings throw insight into the toxicity of cadmium to the common intertidal animals which are either suspension or detritus feeders.

Exploring Indonesian aquaculture futures

Aquaculture is the fastest-growing food production sector globally, with production projected to double within the next 15–20 years. Future growth of aquaculture is essential to providing sustainable supplies of fish in national, regional and global fish food systems; creating jobs; and maintaining fish at affordable levels for resource-poor consumers. To ensure that the anticipated growth of aquaculture remains both economically and ecologically sustainable, we need to better understand the likely patterns of growth, as well as the opportunities and challenges, that these trends present. This knowledge will enable us to better prioritize investments that will help ensure the sustainable development of the sector. In Indonesia, WorldFish and partners have applied a unique methodology to evaluate growth trajectories for aquaculture under various scenarios, as well as the opportunities and challenges these represent. Indonesia is currently the fourth largest aquaculture producer globally, and the sector needs to grow to meet future fish demand. The study overlapped economic and environmental models with quantitative and participatory approaches to understand the future of aquaculture in Indonesia. Such analyses, while not definitive, have provided new understanding of the future supply and demand for seafood in Indonesia stretching to 2030. The learning from this research provides a foundation for future interventions in Indonesian fish food systems, as well as a suite of methodologies that can be applied more widely for insightful analyses of aquaculture growth trajectories in other countries or regions.

Studies on the transportation of live clams

Live clams (Villorita cyprinoides) collected from their natural beds were packed in different ways like dry pack, tray pack, in oxygenated water (wet pack) and depurated samples in wet pack. It was found that the packaging in l kg lots in 200 gauge polythene bags with oxygen at a temperature of 20°C could keep them live for 4 days. In tray pack without oxygen and water they can be kept alive for 3 days at 20°C. Temperature seems to be the critical factor in the transportation of live clams. At room temperature both dry and wet pack can be kept for 24 h only. Depuration technique does not appear to be useful in prolonging the storage life of clams in live condition as percentage mortality is more at 48 h both at 20°C and room temperature compared to the non-depurated samples.

High temperature processing of fish sausage 1. - An improved technique

An improved technique for the preparation of fish sausage (Nemipterus japonicus) over the conventional method (90°degree C for 1 h) has been evolved by processing at a temperature of 115.6°degree C (4.5 kg) for 20 min. The overall quality characteristics of fish sausage, particularly its colour, texture and appearance remained unchanged and the product was in good condition up to 9 days at ambient temperature in contrast to the shelf life of 3 days by conventional method. The design of the equipment used for the processing of fish sausage and the method of operation are described. The keeping quality of the product from an organoleptic stand point was also studied

Filtration in some tropical intertidal bivalves exposed to mercury and cadmium mixtures

Three species of intertidal filter feeding bivalves (Modiolus carvalhoi, Modiolus sp. and Donax spiculum) exposed to mercury and cadmium filtered significantly less volume of water under individual metal and metal mixture stress. Mercury and cadmium in mixtures interacted additively and more than additively (Synergism) in depressing the filtration rate of the bivalves.

High temperature processing of fish sausage 2. - Effect of certain preservatives on the shelf life

The effects of preservatives like fat coated sorbic acid (FCSA) and glucono-deltalactone (D-lactone), both separately and in combination, on the shelf life of high temperature (115.6°C for 20 min) processed fish sausage, stored at three different temperatures namely, ambient (28±2° C), cooler storage (2±2°C) and refrigerator (10±2° C) were studied. Whereas the control (without preservative), FCSA, D-lactone and FCSA + D-lactone treated samples could be stored for 9, 11 and 13 days respectively at ambient temperature, those stored at lower temperatures were found to be in acceptable condition for 70 and 80 days respectively. Organoleptic evaluation of taste, flavour the products carried out by panelists revealed that FCSA and FCSA + D-lactone treated samples were unacceptable with regard to the taste, flavour and texture. However, the taste flavour and texture of the control and D-lactone treated samples were in acceptable condition.

Studies on kraft paper used for liners and corrugating media of shipping containers for frozen shrimp

An examination was made of the physical properties of kraft paper used for liners and corrugating media of shrimp shipping containers in India. Findings stress the need for use of virgin grade kraft paper and adequate waxing treatment on both sides for water proofing.

High temperature processing of fish sausage 3. - Studies on some of the storage characteristics

The proximate composition of the high temperature processed fish sausage was found to be 14.56% protein, 4.65% fat, 69.14% moisture, 2.12% ash and 8.12% carbohydrate. The quality of the product during storage was assessed on the basis of the changes observed in the physical, chemical and microbiological parameters. The results of the different tests such as pH, volatile base nitrogen (VBN), trimethyl amine nitrogen (TMA-N) and jelly strength are summarized and discussed. The total bacterial load increased gradually during storage but was not proportional to the initial load.

High temperature processing of fish sausage 4. - Heat penetration study

An examination was made of the rate of penetration of heat into fish sausage during processing at 115.6°C. Findings showed processing for 24 minutes to bring about complete destruction of Clostridium botulinum. A processing time of 30 minutes destroys almost all spoilage-causing organisms, thus prolonging the shelf life of the products.

Bulk packages for storage and transportation of salted and dried fish

The effect of bulk packaging on the storage of salted and dried fish was studied at ambient conditions. Four different packaging systems were tried, among which gusseted type high density polyethylene woven sacks having either circular loom or traditional loom laminated with 100 gauge low density polyethylene were found to be best suited for dry fish packaging as they could withstand the hazards of handling, transportation and storage.

Development and shelf life evaluation of Tilapia (Orechromis spp.) marinades

Tilapia (Oreochromis spp.) consumption is limited due to its strong muddy odour and the difficulty of processing. In addition, consumption of tilapia is minimal in urban areas because of the low availability. There are no processed market products of tilapia available in Sri Lanka. Therefore, this study was designed to develop a new marinade for tilapia and to evaluate the shelf life of the product. Twelve different treatments of varying amounts of vinegar, salt, chili powder, white pepper and garlic powder were applied to filleted tilapia, and three best treatment combinations were selected using a sensory evaluation test. Processed tilapia was stored in the freezer at -4°C. Treated samples were subjected to evaluation of sensory profile: taste, odour, colour, texture and overall acceptability. Analysis of the shelf life was carried out by using the total plate count, faecal coliform test, acidity and pH at weekly intervals. Results revealed that the third treatment (vinegar 75 ml, salt 5 g, chili powder 5 g, white pepper 5 g and garlic powder 5 g) was best in terms of colour, texture, odour, taste and the overall acceptability according to the estimated medians (6, 6, 6 and 6.33 respectively). There was no significant difference between the first and the third treatment in terms of odour and overall acceptability. There was no significant difference between the three vacuum packed treatments for acidity and pH. Acidity and pH of the three treatments were at an acceptable level, which was below pH 5.3 and above 1.95% acidity. Average bacterial count was 10 colonies and 1.33x10 super(6) colonies respectively in vacuum packed treatments and bottled samples after one week. The acceptable level of bacterial colonies is 1.00x10 super(5). Vacuum packed treatments showed a one month shelf life. In conclusion, marinades can be developed from tilapia with a pleasant taste and acceptable texture.

An assessment of handling and processing methods used for the shrimp fishery by-catch in Kalpitiya, Sri Lanka

The by-catch from the shrimp trawl fishery in Kalpitiya is mainly used for the production of dried fish, which provides an additional source of income for fishermen in the area. It has been observed that current handling practices along the value addition chain are responsible for the poor quality and low price of the end product. This study was aimed at identifying the shortcomings in such handling practices by fishermen and dried fish producers and assessing the quality of shrimp fishery by-catch along the processing chain in order to recommend more efficient utilization methods that will improve the quality of the end product. Fresh fish, dried fish and harbour water samples were tested for total coli forms, faecal coliforms, E. coli and Salmonella in order to assess their microbial quality: In addition, standard plate counts (SPC) of fish samples were also carried out. A survey was carried out from July-October 2006 at Kalpitiya, using a pre-tested questionnaire to collect information from individuals who have been engaged in dried fish processing. Average values obtained for freshly landed and dried fish respectively, were, SPC 9.88x10 super(5) CFU/g and 30.43x10 super(5) CFU/g, total coliforms 23.05 and 24.23 MPN/g and fecal coliforms 8.28 and 9.00 MPN/g. These values exceed the recommendations in the SL standards. A quarter of the landed fresh fish and 38% of dried fish from the producers were positive for E. coli and thus failed to show required end product quality. SPC of harbour water was 14.35x10 super(6) CFU/ml and all samples were found to be contaminated with E. coli. None of the fishermen and dried fish producers were satisfied with the quality of the end product. The reasons for poor quality as indicated by them were: limited availability of ice (75%), lack of infrastructure facilities (65%), uncertainty of markets (52%), lack of emphasis on quality (47%) and poor access to available technologies (41%). Respondents to the questionnaire also identified: unavailability of potable water, insulated boxes, good landing jetty, racks for drying fish, poor cold storage facilities and limitations in dried fish storage facilities, as further factors leading to the loss of quality in their products. Results demonstrate that improvements to the infrastructure facilities and conducting of proper awareness programmes on handling practices could lead for improvements in the quality of value added products prepared from the shrimp fishery by-catch at Kalpitiya.