The study was designed to investigate the effect of low temperature preservation on the chemical and microbial profile of fish muscle (Labeo rohita) stored for a period of twenty one days. The proximate composition and microbiological analyses were carried out at 7 days interval on muscle of fish during frozen storage. It was found that the protein, lipid, moisture and ash contents decreased significantly (P < 0.05) during the entire storage period. In fresh (unfrozen) samples, protein(15.93±0.04%), fat (3.86±0.04% ), moisture (84.74±0.1%.),and ash content (1.79±0.01%) were found to be the highest ,where as the total percent decrease in frozen samples on 21 st day of frozen storage was (12.99% ), (22.27%) , ( 4.60% ) and (24.02% ) for protein, fat, moisture and ash respectively. The microbial count increased gradually during the period of storage. The Total Plate Count in fresh fish muscle on day zero was rather low i.e. 2.44±0.2 log cfu/g as compared to the values found on the 21 st day i.e. 5.10±0.02 log cfu/g. The Coliform Count also followed the same trend during the storage. On day zero, a few colonies were found and the CC was 1.50±0.15 log cfu/g where as it increased up to 3.08±0.07 log cfu/g on last day of storage. Similarly Psychrophillic count increased from 2.15±0.2 log cfu/g on day zero to 5.06±0.05 log cfu/g on 21 st day. Thus, a significant quality loss was observed in fish during storage. However, the present frozen conditions retained the fish under acceptable microbial conditions for human consumption up to 14 th day beyond which it became unfit for human consumption.

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Change In Proximate Composition And Microbial Count By Low Temperaturepreservation In Fish Muscle Of Labeo Rohita(Ham- Buch)

Both the worldwide demand for fish and aquaculture production have increased. Nevertheless, an extensive amount of fish production is destined for animal feed. Fish represents a rich source of nutrients necessary for good health, but it is highly perishable. This review contains descriptions of the relevance of the use of mechanically separated fish meat, which is considered a waste processing, for the manufacturing of semi- and ready-to-eat (RTE) products for human consumption and an evaluation of their chemical stability. Currently, consumers request nontraditional foods without risk to their health. Therefore, the development of innovative and healthy foods has been a challenge, mainly due to lack of knowledge and technology transfer to the industry.

https://www.tandfonline.com/doi/pdf/10.1080/19476337.2015.1087050

Ready-to-eat products elaborated with mechanically separated fish meat from waste processing: challenges and chemical quality

Large quantities of commercially important juvenile fishes are fished as bycatches and were discarded as waste. For food control this was utilized for the development of edible fish powder and their quality, shelf life and it was incorporated with normal food items and their consumer acceptance were assessed to eradicate malnutrition.

Utilization of Trash Fishes as Edible Fish Powder and its Quality Characteristics and Consumer Acceptance

Microbiological analysis of Tilapia guineensis was assessed at two ice stored temperatures, -18 and 4°C, for 4 weeks. Bacteria and fungi counts decreased from 7.9 × 103 to 5.4 × 101 cfu/g for bacteria and 6.2 × 103 to 3.2 × 102 cfu/g for fungi in the samples stored at -18°C, while for the samples stored at 4°C, an increase was shown in counts from 7.9 × 103 to 7.6 × 107 cfu/g for bacteria and 6.2 × 103 to 6.8 × 104 cfu/g for fungi. Pseudomonas, Staphylococcus, Bacillus,Proteus, Micrococcus and Aeromonas sp. were the bacteria species isolated before cold storage, while only Pseudomonas, Staphylococcus, Bacillus andProteus sp. were isolated from samples stored at -18°C. The same organisms isolated before cold storage were also isolated for samples stored at 4°C. Fungal species isolated before cold storage include: Cladiosporium, Aspergillus andFusarium sp. All these fungi species were also isolated from samples stored at -18°C. Cladiosporium, Pichia, Aspergillus and Fusarium sp. were isolated from samples stored at 4°C. The level of bacteria and fungal growth in fish stored at 4°C temperature exceeded the acceptable microbiological limits (102/g for moulds and 103/g for bacteria). However, the pH of fish was found to increase in the two stored temperatures. It was within the alkaline range in the -18°C stored samples, but within the acidic range in the 4°C stored samples. There were significant differences (P<0.05) in the microbiological composition of the ice stored Tilapia guineensis within the same temperature and between the two temperatures. The quality of the 4°C stored sample deteriorated faster than that of the -18°C. Thus, storage temperature and duration have effects on the quality of stored fish.

	 

	Key words: Tilapia guineensis, fish, sample, bacteria.

Microbiological assessment of stored Tilapia guineensis

The present study assessed the effect of hot smoke using wood and charcoal dry heat on keeping quality of Trachurus trachurus fish fillet, skin, head and bones (SHB) T trachurus was smoked using the altona kiln at 80 to 105°C for eight hours, placed in cain woven baskets to cool off, packaged in sealed transparent polythene bags and left on shelf for 7 days at ambient temperature (32 ± 2°C) Biochemical indexes assayed were: pH, total volatile nitrogen (TVBN), peroxide value (PV) and total viable count (TVC) pH of raw T trachurus fillet was 685 ± 000 but significantly reduced with wood smoke at day 0 to 670 ± 002, while TVBN in raw T trachurusfillet was 2717 ± 161 mgN/100 g After smoking, TVBN of T trachurus fillet at day 0 was 2183 ± 038 mgN/100 g (wood) and 2305 ± 136 mgN/100 g (charcoal) pH of raw T Trachurus SHB was 587 ± 003 and increased (p<005) with smoking, that is, 643 ± 021 (wood) and 643 ± 000 (charcoal) TVBN in the raw T Trachurus SHB was 2812 ± 217 mgN/100 g, and after smoking on day 0, it was 3190 ± 03 mgN/100 g (wood smoked) and 2444 ± 190 mgN/100 g (coal smoked) The PV was highest in charcoal smoked SHB (CSHB) of T trachurus at day 5(10840±3680) and TVC was highest in the CSHB on day 5 (348 logcfu/g) The overall study showed that T trachurus fish samples (fillet and SHB) prepared via charcoal smoking method had the lowest (p<005) storage time amongst the smoked fish samples, when compared with those that were processed via wood smoke

	 

	Key words: Trachurus trachurus, ambient temperature, smoked fish and seafood quality

https://africaneditors.org/journal/AJBR/full-text-pdf/77966-107143

Stability study of smoked fish, horse mackerel (Trachurus trachurus) by different methods and storage at room temperature

Nile perch, the most important commercial fish species from the Lake Victoria fishery, contributes about 67% of Kenya’s total annual fish export earnings. Despite the Nile perch being an important foreign exchange earner, little information is available on its nutritional composition and shelf life on ice, information that is necessary for the development of methods to maintain its freshness, especially in view of the occasional rejection of exports of Nile perch products by the European Union. This study was, therefore, conducted using a set of physicochemical parameters to follow its deterioration profile in order to estimate its shelf life and freshness in the course of storage. These sensory parameters were correlated with selected biochemical and microbiological parameters to assess the suitability of the quality index scheme developed to determine the quality and shelf life of the iced Nile perch in the course of storage. The protein, lipid, moisture and ash contents were determined. The pH, total volatile basic nitrogen (TVBN), TMAO and free fatty acids (FFA) contents were the biochemical parameters studied, while total viable counts (TVC) and hydrogen sulphide producing bacterial counts were the microbiological parameters studied at the various stages of storage. The results showed that protein in the edible tissue of the Nile perch varied significantly (p storage time (p>0.05). The sensory characteristics selected for the quality index scheme increased from 3.3 demerit points to 18.1 points (out of 20) at the point of rejection by a sensory panel. The TVBN increased from 8.4±0.7 mgN/100g to 26.0±0.9 mgN/ 100g at the point of rejection. No TMAO was detected. The %FFA increased from 1.9 to 2.7% at the point of rejection, while the TVC and hydrogen sulphide producing bacterial counts increased from 6.6 log cfu/g to 8.0 log cfu/g and 4.3 log cfu/g to 7.3 log cfu/g, respectively. The study established that the ungutted iced Nile perch handled under normal conditions in this fishery with a delay of 3-4 hours before icing, had shelf life of 22 days, while the control which was iced on board had a shelf life of 28 days. The study is significant in designing programmes for reducing post harvest losses of this fish in the Lake Victoria fishery.

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Nutritional Composition And Shelflife Of The Lake Victoria Nile Perch (Lates Niloticus ) Stored In Ice

Currently, the Kenya fisheries industry does not have an official grading scheme for fresh fish. Due to lack of an appropriate and locally developed grading scheme, this study used the Quality Index Method to develop a grading scheme for iced Rabbitfish and White snapper through a shelf life study. The two fish were bought from fishermen at the landing beach after delayed icing of 4-6 hr. The two fish were placed into gutted and ungutted lots. Both lots were layered with ice and stored in insulated boxes. Three iced fish from each batch were sampled on days 4, 8, 12, 16, 20, 24 and 30 for ungutted lots but up to 34 days for the gutted fish. Sensory attributes of the fish including appearance of skin, color of slime, color and odor of gills were selected for development of a quality index scheme by a trained sensory panel. Total viable counts (TVC) were determined at 22 and 37 o C as well as hydrogen sulphide-producing bacterial counts at 22 o C. Free fatty acid level, pH and total volatile basic nitrogen were also determined on experimental fish over the storage period. The shelf life of gutted Rabbitfish and White snapper was 32 and 28 days, respectively; ungutted Rabbitfish and White snapper, had shelf lives of 28 and 24 days, respectively. The TVC and hydrogen sulphide-producing bacterial log was 6.1±0.21 and 5.8±0.55 CFU/g at the point of rejection of ungutted Rabbitfish and log 6.3±0.24 and 5.8±0.28 CFU/g for ungutted White snapper. For gutted Rabbitfish and White snapper, TVC and hydrogen sulphide-producing bacterial log were 5.9±0.19 and 5.3±0.11 CFU/g and log 5.9±0.22 and 5.4±0.21 CFU/g, respectively at point of rejection by the taste panel. Gutting the two fish species increased shelf life by about 4 days. The quality index scheme developed in this work was appropriate for creating commercial grades of the two marine fish. The select sensory parameters and QI are suitable, while TVBN, FFA, pH, TVC and hydrogen sulphide-producing bacterial count are not appropriate for rapid commercial grading of fresh, ice-stored White snapper and Rabbitfish. Key words: Grading, White snapper, Rabbitfish, ice, quality index

G. O. Okeyo

Papers

Nutritional Composition And Shelflife Of The Lake Victoria Nile Perch (Lates Niloticus ) Stored In Ice

Creating a grading scheme for fresh ice-stored White snapper (Lutjanidae spp.) and Rabbit fish (Siganus sutor) using quality indices