Investigation on sanitational aspects (microbiological) of prawn processing factories

Absence of regular cleaning has been found to result in heavy bacterial loads on the surfaces of utensils and other equipment used in prawn processing factories and peeling centers. Instance of high faecal contamination is also sometimes met with. Detailed investigations have shown that a cleaning schedule comprising of treatment of these surface with a detergent followed by application of an effective disinfectant like sodium hypochlorite would prevent such bacterial build up.

Bacterial quality and depuration of the green mussel Perna viridis from natural beds

Green mussel (Perna viridis) and sea water from their natural beds on the coastal areas of Porto Novo were studied between April and August 1996 for their bacterial quality. Water samples from the beds were also analysed for their physico-chemical parameters. The total bacterial count of mussels from natural beds as well as bed waters ranged 10³ organisms per gram of mussel meat suspension and per milliliter of sea water. The faecal coliforms were found to be within the permissible limits. Pathogenic bacteria such as Salmonella spp., Streptococcus spp. and Staphylococcus spp. were absent. The variations in pH, temperature, salinity and dissolved oxygen of the seawater samples were insignificant. The mussels were subjected to depuration by different methods among which chlorination was found to be most effective.

Fish-makhana (Euryale salisb) integration: a case study of sustainable aquafarming system in north Bihar

The paper deals with a technique to synchronize two crops, fish and makhana (Euryale ferox Salisb) in a pond. In such eco-friendly integration both crops are mutually benefited. Decomposed plant parts of makhana crop form organic matter that releases nutrients in the water to enhance plankton population. Organic detritus not only acts as food for bottom dwelling fishes (mrigal and common carp) but also provides a suitable substratum for the growth of zooplankton, insect larvae, nematodes and gastropods. Fishes contribute to the control of makhana pests. Their faecal matter acts as organic manure for makhana crop. Plankton population fluctuated between 1260 u/l to 4030 u/l in the control pond and 1630 u/l to 4722 u/l in the experimental pond. During the grand growth period of makhana crop (April to July) the dissolved oxygen content fluctuated between 5.02 mg/l to 6.68 mg/l in the covered areas and 6.04 mg/l to 6.92 mg/l in uncovered areas. Makhana leaves acting as blanket barrier over the water surface brought down the D.O. content in the covered areas of the pond. Free CO sub(2) content showed wider fluctuation in the experimental pond (25.2 mg/l to 30.9 mg/l) than in the control pond (25.1 mg/l to 28.6 mg/l). This could be due to decomposition of plant parts of the presiding crop lying as debris at the pond bottom. Autochthonous supply of nutrients enhanced the content of nitrogen, phosphorous and organic carbon in the soil of experimental pond. The experimental pond covering an area of 0.40 ha yielded 852 kg fish and 200 kg pops whereas the control pond covering the same area produced 777 kg fish only. The net profit per ha came out to be Rs.1,04,700 and Rs. 66,200 in integrated and non-integrated system respectively. Owing to crop diversification, the present integrated system was found to be more viable than the non-integrated system in terms of production and net profit.

A bacteriological study of the natural flora of edible oyster, Crassostrea madrasensis

The total viable bacterial populations in the oysters and the sea water from the edible oyster farm at Tuticorin were in the range of 10 super(3) to 10 super(4) per ml and 1 super(2) to 10 super(3) per ml respectively. The maximum most probable number of faecal coliform recorded during the one year period of study of both the oysters and seawater were 33 per 100 ml. Pathogenic bacteria (Salmonella sp., Vibrio cholerae, coagulase positive staphylococci and faecal streptococci were absent in oysters and farm water. Study of 197 (98 taken from oyster liquid and 99 from oyster farm water) randomly isolated cultures indicated that gram negative asporogenus rod-like bacteria of the Vibrio, Flavobacterium, Achromobacter and Pseudomonas groups were the dominant flora of the oyster liquid as well as seawater.

Evaluation of organoleptic qualities of fish grown in ponds treated with different organic manures

Catla, rohu, silver carp and common carp raised employing different organic manures were subjected to organoleptic evaluation, both in raw and cooked form. The combination treatment of poultry manure and silkworm faecal matter had positive effect on colour and glossiness of skin and colour of flesh in the case of common carp. Though no significant difference was observed in the overall quality, odour of flesh and texture of meat of rohu were found to be better in sewage treated and poultry manure treated ponds respectively. From the results, it can be discerned that treated sewage has no adverse effect on the acceptable qualities of the carps studied.

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.

Studies on the occurrence of enteric bacteria in the estuarine waters along the Mangalore coast

Occurrence of enteric bacteria in water, sediment and shellfishes of Mulki, Pavanje, Gurpur and Netravathi estuaries of the Mangalore coast is reported. 70 water samples, 71 sediment samples and 37 shellfish samples were analysed in 18 months. Total bacterial load in sediment and shellfishes was found to be more than that in water samples. The total bacterial load was not very high. However, enterococci, particularly coliforms in sediments, water and shellfishes were found to be quite high, indicative of faecal pollution. The incidence of Salmonella spp. was recorded in all the estuaries except the Mulki estuary.

Quality of certain ready-to-eat fish products of the domestic trade

Quality of 181 samples of ready-to-eat fish products comprising fried fish, fish curry and fish/prawn pickles collected from Cochin and Calicut were studied. Salmonella was absent in all the samples. V. cholerae was tested in the samples collected at Cochin and was absent in all the cases. Coliforms, E. coli, faecal streptococci and coagulase-positive staphylococci were present in some of the samples studied. The study indicated the necessity to improve the sanitary and hygienic conditions of the hotels engaged in the preparation of these products. The study further indicated that fried fish and fish curry shall not be served after 6 hours of their preparation. Added care is to be exercised in the selection of shrimps and fish for the preparation of pickles.

Quality of fish in retail markets of Bombay

Study carried out on the quality of fresh fish in retail markets of Bombay revealed that only 75% of the samples were of acceptable quality. Incidence of faecal streptococci was generally high, indicating poor sanitary and hygienic practices in handling of fresh fish. Total bacterial counts higher than Indian standard specified limits were observed in more than one third of the samples analysed. 7.5% of the samples were found to be contaminated either with Salmonella or Clostridium perfringens, thus posing a serious potential health hazard to the consumer. The quality of fish in different markets is also discussed. The urgent need for formulation and implementation of quality standards for fresh fish in domestic trade is highlighted.

Impact of species composition and artificial feed on the growth of carps

Two trials conducted to demonstrate the suitability of composite carp culture in a small, seasonal, shallow village pond with varied species composition and stocking density indicated the possibility of obtaining higher production with reduced number of species. During the first trial, the Indian major carps, silver carp, common carp and fringe lipped carp were stocked at a density of 5625 fingerlings/ha in the pond in which the maximum water spread area was 1600m². The fish grown over a period of seven months yielded a production of only 242 kg. However, during the second trial, an increase in production by 60.33% was achieved over the same period in the same pond by stocking only the Indian major carps and common carp at a density of 4687.5 fingerlings/ha and feeding them daily with silkworm faecal matter based artificial feed at about 5% of their body weight. The results indicated that for seasonal, shallow ponds stocking of only three species of carps, namely, catla, rohu and common carp would suffice to get optimum yield.

Quality of commercial frozen boiled clam meat

The bacterial quality and sand content of commercial frozen boiled clam meat are discussed. In general the commercial frozen boiled clam meat belonging to the Villorita cyprinoides sp. collected from Cochin are highly contaminated with faecal indicator and pathogenic organisms than that belonging to the Katelysia opima sp. collected from Quilon. The studies also show that the bacterial quality of frozen boiled clam meat can be improved by enforcing better hygienic and sanitary practices.

Ferrocement buoys for mussel culture

A method is described for culturing mussels (Mytilus smaragdinus) using ferrocement buoys, which may be used in the construction of a raft house or a flotation system for nets and cages.

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.

The potential of Nakivubo swamp (papyrus wetland) in maintaining water quality of inner Murchison bay - Lake Victoria

Nakivubo swamp (papyrus wetland) is located in the south east of the city of Kampala, Uganda. This swamp has been receiving waste water from Nakivubo channel for more than two decades. This investigation was aimed at monitoring the level of pollutants (nutrients and faecal coliforms) as the waste water filtrates through the swamp and the flow patterns of waste water through the swamp. From this preliminary investigation it was found out that the waste water is not evenly distributed over the swamp. Also high levels of pollutants seem to filtrate through the swamp and enter Inner Murchison Bay - Lake Victoria. Further research is under way to investigate in more detail the capacity of Nakivubo swamp to remove nutrients/pollutants from waste water flowing through it and the dominant mechanisms/processes involved.