Combined Effect of Gamma Irradiation and Low Temperature Storage on the Microbial and Bio-chemical Quality of Sutchi Cat Fish (Pangasius hypophthalmus)
Mahendra Uikey
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Manjanaik Bojayanaik *
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Jyoti Ganachari
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Darren Jeeth Fernandes
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Srinu Nayak Banavath
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Sagar Naik Chandra Naik
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Sachin Chavan Dnyanoba
Department of Fish Processing Technology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore – 575002, India.
Veena Shetty Alandur
Department of Microbiology, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangalore- 575018, India.
Somashekarappa Hiriyur
Centre for Application of Radioisotopes and Radiation Technology (CARRT), University, Konaje, Mangalore-574199, India.
*Author to whom correspondence should be addressed.
Abstract
Gamma irradiation is known as an effective method to reduce microbial contamination in food products. Its application in seafood food not only enhances safety and quality but also extends shelf life, thereby minimizing post-harvest losses. This study focuses on evaluating the combined effect of low dose gamma irradiation and low-temperature storage on the quality and shelf life of fresh Sutchi Catfish (Pangasius hypophthalmus). The fish samples were subjected to different gamma irradiation doses (0.0 kGy, 1.0 kGy, 3.0 kGy, and 5.0 kGy) and then stored under refrigerated conditions (4°C) and frozen conditions (-18°C). Both non-irradiated and irradiated samples were periodically analyzed for microbial counts, including coliforms (total and fecal), total mesophilic bacteria, Salmonella, E. coli, and Staphylococcus aureus. The biochemical quality indices such as total volatile base nitrogen (TVB-N), pH, peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) were also assessed at regular intervals.
The findings revealed that the gamma irradiation and storage at low temperatures significantly (p < 0.05) reduced microbial populations, with higher irradiation doses resulting in greater reductions. Chemical quality indicators in irradiated samples were notably better maintained compared to the control samples under both storage conditions. The study concluded that combining gamma irradiation with refrigeration or freezing effectively minimized microbial loads and preserved biochemical quality. This approach extended the shelf life of the fish up to 21 days in refrigeration and 90 days under frozen storage conditions.
Keywords: Gamma irradiation, frozen storage, microbial quality, PV, TBARS, Sutchi Cat fish