Functional and structural characteristics of chocolate flavoured cake incorporated with surimi powder from Nemipterus species.

Surimi is the concentrated myofibrillar protein extracted from fish. In this study, surimi prepared from Nemipterus species of fish was dried by two methods such as freeze drying and oven drying and was pulverized and sieved. The maida to bake chocolate flavoured cakes was replaced at 10% with freeze dried surimi powder (FDS) and oven dried surimi (ODS) powder separately. The aim of the study was to analyse the functional and structural characteristics of chocolate flavoured cake incorporated with surimi powder from Nemipterus Species. The functional characteristics of the ingredients and cakes were analysed by Fourier Transform Infrared Spectroscopy and assignments of the peaks were assigned. The presence of shifts of peak around 1550 cm-1 in cakes as compared to the ingredients suggested a change in protein structure. FTIR spectra of ingredients and cake indicated the changes in protein structure in the cakes, probably due to the exposure of cakes to higher temperature during baking. Scanning electron microscopic images of control cake, cake incorporated with 10% FDS powder and cake incorporated with 10% ODS powder revealed the presence of large number of pores in all the cakes. FDS cakes had higher number of micro-pores than control and ODS cakes. Evenness in structure was higher in control cake than FDS and ODS cakes.

Occurrence of Listeria monocytogenes on the seafood contact surfaces of Tuticorin Coast of India.

Listeria monocytogenes was screened from different seafood contact surfaces in five sampling sites of fishing harbour, fish landing centers, seafood processing plants, fish market, and fish curing yards of Tuticorin Coast of India. 115 swab samples were collected and tested for the occurrence of L. monocytogenes by conventional and molecular methods. Overall, 5.22% of swab samples collected were positive for L. monocytogenes. The fishing harbour had high incidence (10.3%) of L. monocytogenes followed by fish landing centers (5.9%), and seafood processing plants (4.1%). Boat deck, fish transport tricycle were the two seafood contact surfaces in fishing harbour, which had the occurrence of L. monocytogenes. The swab samples from fish market and fish curing yards were negative for L. monocytogenes. All the isolated colonies of L. monocytogenes were confirmed by PCR assay targeting virulent hlyA gene. The DNA of all the isolates yielded a product of 174 bp on PCR amplification in comparison with L. monocytogenes Type culture (MTCC 1143). The results clearly indicated the occurrence of L. monocytogenes in seafood contact surfaces along the Tuticorin Coast of India.

Sensory, biochemical and bacteriological properties of octopus (Cistopus indicus) stored in ice.

Octopus (Cistopus indicus) were examined for the changes in autolytic activity, ammoniacal nitrogen, non-protein nitrogen (NPN), total volatile base nitrogen (TVBN), free fatty acid (FFA) content, aerobic plate count (APC) and sensory quality based on Quality Index Method (QIM) during ice storage. They were sensorily acceptable up to 7 days when QIM score was 10.97 out of 16.00. Autolytic activity increased from the initial value of 174 to 619 nmoles Tyr/g/h within day 3 and later decreased. There was also an increase in NPN (34.88 to 76.16 mg %), ammoniacal nitrogen (0 to 7.30 ppm) and free fatty acid content (0.35 to 1.69 % of oleic acid) during storage. TVBN values did not correlate with the spoilage, as it increased from 28 to 145 mg% within day 5, exceeding the limit of acceptability; although total QIM score was 7.47. Aerobic plate count did not show significant change suggesting that the spoilage in octopus was not microbial. The rapid spoilage in octopus was mainly due to the release of NPN compounds following autolytic activity leading to the formation of ammoniacal nitrogen, rather than microbial spoilage. Hence, ammoniacal nitrogen can be taken as an index for spoilage of ice stored octopus.

Processing and storage of restructured surimi stew product in retortable pouches.

Restructured surimi gel product was prepared using short nosed white tripod (Triacanthus brevirosterus) with egg white as additive at 1 %. Heat setting was done initially at 45 °C for 30 min followed by heat processing 90 °C for 45 min. Restructured surimi gel in stew was standardized using four most popular recipes available in local cuisine based on the sensory acceptance and the Kerala fish stew was considered best. Restructured surimi gel in Kerala fish stew was then heat processed in 4 ply laminated retort pouch of dimension 150× 200 mm, at 15 psi gauge pressure for varying time duration and the Fo values ranged from 13.10 to 22.58 min. Products examined of their organoleptic and microbial qualities showed those processed with Fo value of 13.10 min was acceptable with excellent eating quality with no fishy flavour and was microbial sterile until the storage period of 6 months.

Detection of hemolytic strains of Aeromonas hydrophila and A . sobria along with other Aeromonas spp. from fish and fishery products by multiplex PCR.

Hemolytic strains of Aeromonas spp. from fish and fishery products were detected by multiplex PCR. The selected primers for the amplification of segments of ahh1, asa1 and 16S rRNA gene yielded products with the size of 130 bp, 249 bp and 356 bp, respectively. This assay was found to be highly sensitive, as it could detect 7 and 9 cells of Aeromonas hydrophila and A. sobria with a detection limit of 1 pg of pure genomic DNA. The assay, when screened for 73 commercial fish and fishery product samples consisting of freshwater, marine fish and shellfish, showed 56 % positive for Aeromonas spp., 16 % for Aeromonas hydrophila and 13 % for A. sobria. This assay provides specific and reliable results and can be a powerful tool for the simultaneous detection of hemolytic strains of A. hydrophila A. sobria and other Aeromonas spp. from fish and fishery products.

Quality and safety of fish curry processed by sous vide cook chilled and hot filled technology process during refrigerated storage.

Fish curry, a traditional Indian dish was prepared from farmed fish Cobia (Rachycentron canadum), packaged by two different cook-chill processes namely, sous vide cook chilled and hot filled technology and held at 2 °C. Biochemical composition revealed that fish curry contained 5% protein and 6% fat. Omega-3 fatty acids, eicosapentaenoic acid (EPA) retained 55.44% while docosahexaenoic acid (DHA) retained 29% during cook-chilling process. The major fatty acids in fish curry were C18:2, C12:0, C16:0 and C18:1. Shelf-life of sous vide cook chilled and hot filled technology processed fish curry were 8 and 12 weeks, respectively. Total bacterial counts were detected after 4 weeks and 12 weeks in sous vide cook chilled and hot filled technology processes, respectively. Total staphylococci were detected in sous vide cook chilled and hot filled technology processed cobia fish curry after 4 and 12 weeks, respectively. Total bacilli, anaerobic sulfite reducing clostridia, Salmonella, and lactic acid bacteria were absent. Hot filled technology process was more efficient and could be applied for chilled fish curry preservation for 12 weeks without any safety problems.

Effect of processing treatments on the white spot syndrome virus DNA in farmed shrimps (Penaeus monodon).

AIMS: To investigate the effect of processing treatments on the destruction of white spot syndrome virus (WSSV) DNA in WSSV-infected farmed shrimps (Penaeus monodon). METHODS AND RESULTS: The presence of WSSV was tested by single step and nested polymerase chain reaction (PCR). The primers 1s5 & 1a16 and IK1 & IK2 were used for the single step PCR and primers IK1 & IK2-IK3 & IK4 were used for the nested PCR. Various processing treatments such as icing, freezing, cooking, cooking followed by slow freezing, cooking followed by quick freezing, canning, and cold storage were employed to destroy the WSSV DNA. Of the processing treatments given, cooking followed by quick freezing was efficient in destroying WSSV DNA in WSSV-infected shrimp products. Canning, and cooking followed by slow freezing process had some destructive effect on the WSSV DNA, as WSSV DNA in such processed shrimp products was detected only by nested PCR. Icing, slow freezing, quick freezing, and cooking processes had no effect on the destruction of WSSV DNA. A gradual increase in the destruction of WSSV DNA was observed as the cold storage period increased. CONCLUSION: The results indicated that cooking followed by quick freezing process destroy the WSSV DNA. SIGNIFICANCE AND IMPACT OF THE STUDY: WSSV can be destroyed by cooking followed by quick freezing and this combined process can reduce the disease transmission risks from commodity shrimps to native shrimps.

Stability of chloramphenicol residues in shrimp subjected to heat processing treatments.

The stability of chloramphenicol residues in white shrimp (Penaeus indicus) subjected to cooking (100 degrees C) for 10, 20 and 30 min (C1, C2 and C3) as well as retorting (121 degrees C) for 10 and 15 min (R1 and R2) was studied by a microbial assay method using Photobacterium leiognathi as the test organism. The microbial assay method was found to have a good sensitivity of 1 microg/ml the loss of chloramphenicol in shrimp subjected to cooking for 10, 20 and 30 min was 6%, 12% and 29%, respectively. Similarly, the loss was 9% and 16% from the shrimp subjected to retorting for 10 and 15 min, respectively. The loss of chloramphenicol was found to increase with increase in temperature and duration of heating. This study showed that chloramphenicol is an unstable aquaculture drug that is destroyed or degrades during heat processing treatments.