Quality problems in fish processing

Various problems associated with the quality of the fishery products like spoilage, discolouration, microbiological problems, etc., are outlined. The reasons and remedial measures are discussed. The importance of proper handling, processing and hygiene is stressed

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Not AvailableFresh water fish, Labeo rohita was exposed to sublethal concentrations (0.25, 0.5 and 1.0 mg l-1) of the organophosphorus insecticide, methyl parathion (MP) for 15, 30 and 45 days. Aspartate and alanine amino transferase activity increased with increasing pesticide concentration, suggesting tissue damage and muscular harm due to exposure to methyl parathion. The increase in the activity of alkaline phosphatase suggests an increase in lysosomal mobilization and cell necrosis due to methyl parathion toxicity. The results clearly indicate that the organophosphorus insecticide methyl parathion is toxic at sublethal level and it affects intermediary metabolism of Labeo rohita.Not Availabl

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Not AvailablePesticides and polychlorinated biphenyls (PCBs) are ubiquitous toxic constituents due to their bioaccumulation and specific physicochemical properties. These compounds accumulate in the biota of all levels and the residues are present in all environmental compartments from all geographical areas. Elevated pollutant concentrations are generally the consequence of effluent discharge and agricultural and industrial runoffs. Although majority of these compounds enter the environment through anthropogenic activitiesa, marine algae and invertebrates and natural processes such as forest fire also contribute their share. The development of global quality assurance criteria and the general awareness of the consumer for quality of the food forced a new approach in the quality aspects of food commodities and seafood is no exception to this. In the light of strigent safety measures with respect to seafood imposed by EU and other developed countries, the understanding on pesticides and PCBs assumes significance. Though present in extremely low concentrations, they definitely pose a chronic health hazard. However, the major problem, associated with these chemicals was their method of detection . The advancement of gas chromatographic and HPLC systems has made it possible to quantify these toxic chemicals for the benefit of the mankind. This paper provides an insight into the general aspects of pesticides and PCBs besides highlighting the health hazards, bioaccumulation in sediments, fish and other aquatic biota and their relevance to the quality assurance system of seafood.Not Availabl

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Not AvailableThe effect of exposure to sublethal concentrations of methylparathion on enzyme activities in the liver of rohu, Labeo rohita, was studied during 96 h exposure. Alterations were observed in alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and acid phosphatase (ACP) activities in the liver of L. rohita, of mean size 75 ± 6 g. ALP and ASP activity levels in methylparathion treated fishes were significantly (p<0.05) higher than the control fishes. The LDH activity in the liver of L. rohita after methylparathion exposure was two-fold higher (p<0.05) when compared to control. These results revealed that methylparathion affects the intermediary metabolism of L. rohita and that the assayed enzymes can work as good biomarkers of methylparathion contamination.Not Availabl

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Not AvailableAllergenicity to crustaceans is a global food safety concern in spite of acceptance of delicacies like shrimps, crabs and lobsters. They are also the leading causative of food induced anaphylaxis. Major percentage of allergic reactions are triggered by allergic protein, tropomyosin and the others such as arginine kinase, sarcoplasmic calcium-binding protein, myosin light chain, troponin C, hemocyanin are also involved. Prevalence of crustacean allergenicty, allergens reported in different crustaceans and their cross reactivities are discussed in this reviews. Besides the effect of various thermal and non-thermal processing techniques in managing the crustacean allergen is also discussed. In comparison to the enhanced allergenicity effects reported by thermal techniques, novel non-thermal techniques like high pressure processing, gamma irradiation, enzymic hydrolysis, high intensity ultrasound, pulsed ultraviolet light etc have promising effects on allergenicity reduction by structural modifications in the proteins. The advantages of combined treatments in hurdle technology approaches can make effective mitigation of crustacean allergenicity and can be suitably optimized for hypoallergic food development.Not Availabl

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Not AvailableSeafood industries widely use phosphate dip treatment along with salt to improve the water retention properties of frozen products. Phosphates are GRAS chemical additives with a recommended maximum level of 2,200 mg per Kg in fish and fishery products. Though many combinations are in practise and many researches established different effective combinations, the residue levels were found to be falling out of the limits of regulations. This study optimizes the phosphate dip treatment in Penaeus indicus using Response Surface Methodology to get a safe residue level in the final product. BoxBehnken design with four factors, two levels - phosphate concentration, salt concentration, shrimp to dipping solution volume ratio, and treatment time used to design the experiment. Total phosphorous, weight gain, moisture content, texture and colour properties were investigated as response factors. The suggested models were verified to get a maximum weight gain and safe level of phosphate residue within 7 hrs of treatment. It is concluded that the phosphate residue, within recommended level, is achievable through different combination of initial phosphate concentration, salt concentration, dipping solution volume and treatment time.Not Availabl

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Not AvailableThough myctophids are widely distributed in the Indian oceanic waters and contribute to a large proportion of the deep-sea fish biomass, the information regarding the presence of lipophilic chemical contaminants and heavy metals in these lipid-rich lantern fishes are relatively scanty. Analyses on the occurrence of heavy metals, organochlorine (OCPs) and polychlorobiphenyls (PCBs) in myctophids from Indian waters showed presence of organochlorine pesticides in Diaphus watasei, Diaphus luetkeni and Myctophum obtusirostre. The prominent pesticides detected in the fish tissue include endrin, dieldrin, heptachlor epoxide, α-BHC and heptachlor. Dieldrin and heptachlor epoxide were detected in M. obtusirostre while DDT isomers in D. luetkeni. The total PCB levels followed the order D. luetkeni> D. watasei>M. obtusirostre and 2, 2’, 3’, 4, 5 – pentachlorobiphenyl and 2, 3, 3’, 4’, 6- pentachlorobiphenyl. Trace metals (Fe, Zn, Cu and Mn) Composition is comparable with other fish species reported and followed the order D. luetkeni> M. obtusirostre> D. watasei. Results showed that POPs and heavy metal levels in myctophid species studied were much below the regulatory limits.Not Availabl

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Not AvailableThe physicochemical properties of muscle proteins extracted from two different weight groups (500 and 1500 g) of barracuda (Sphyraena jello) are discussed. Solubility of sarcoplasmic protein (SPP) from groups I and II fishes were 107 and 167.18 mg per g, respectively. The myofibrillar protein (MFP) concentration was significantly higher in group II. The concentration of reactive sulphydryl group and Ca2+ ATPase activity of MFP were higher in group II fishes than in group I fishes. Surface hydrophobicity of MFP was noticeably higher for group I fishes compared to the other group. High emulsion activity index (EAI) was noticed for group I fishes. EAI of SPP increased but that of MFP decreased with increase in protein concentration in both the fishes. MFP from group I fishes showed better emulsion stability (ES) and the ES showed concentration-dependent increase in both groups for both SPP and MFP. Foam expansion was higher in group I fishes, but foam volume stability (FVS) of both the groups did not show any significant difference. Viscosity, water holding capacity (WHC) and gel strength (GS) were higher for group I fishes. Electrophoretogram of SPP and MFP of both the groups show difference in band pattern indicating that proteins expressed during various stages of growth vary.Not Availabl