MICROBIOLOGICAL, CHEMICAL AND ORGANOLEPTIC EVALUATION OF FRESH FISH AND ITS PRODUCTS IRRADIATED BY GAMMA RAYS

Abstract

The present study evaluated the microbiological, chemical, and organoleptic aspects of irradiated fresh fish and its products to extend their shelf life. Fresh fish and its products were irradiated at three doses (1.5, 3.0, and 4.5 kGy) used for preservation to study the effects of irradiation on their microbiological properties, fatty acid composition, and organoleptic properties. Irradiated fresh bolti fish, smoked herring, and smoked mackerel were evaluated microbiologically, chemically, and organoleptically. Radiation treatment not only reduced the counts of aerobic bacteria, fecal streptococci, molds, and yeasts but also destroyed all the Staphylococcus aureus cells, improving the hygienic quality of the fresh and smoked fish samples. Irradiation increased the peroxide, acid, and thiobarbituric acid values, but they remained within acceptable levels. No new fatty acids or other artifacts due to irradiation were observed. Irradiation of 4.5 kGy greatly reduced the organoleptic quality scores of fresh bolti fish, indicating that the optimum radiation dose for this fish was 3.0 kGy. Smoked herring and mackerel could be irradiated with up to 4.5 kGy without adverse effects on their organoleptic properties.