IMPROVING THE QUALITY OF READY-TO-EAT MEALS BY GAMMA IRRADIATION 1- COOKED MEAT BALLS AND MASHED POTATOES

摘要

The possibility of using gamma irradiation for improving the quality of ready-to-eat cooked meat balls and mashed potatoes was studied. The prepared samples of meat balls and mashed potatoes were subjected to gamma irradiation at doses of 0, 1.5, 3 and 4.5 KGy followed by cold storage (4 ± 1℃). The effects of irradiation and cold storage on the microbiological aspects, chemical and organoleptic properties of samples were studied. The results showed that irradiation of the prepared meal components decreased their microbial counts (total bacteria, total psychrophilic bacteria and total yeast and molds), proportionally to the applied dose and prolonged their refrigerated shelf-life. Moreover, irradiation at 1.5 KGy reduced the counts of Enterobacteriaceae, Staphylococcus aureus and Enterococcus faecalis, while 3 KGy dose completely eliminated the presence of Enterobacteriaceae and Staphylococcus aureus and greatly reduced the counts of Enterococcus faecalis in samples. Salmonella was not detected in all irradiated and non-irradiated samples. On the other hand, gamma irradiation had no effects on the chemical composition and pH of meal components but increased the thiobarbituric acid (TBA) values of cooked meat balls. However, cold storage gradually increased the values of TBA in irradiated and non-irradiated cooked meat balls. Moreover, cold storage induced slight and gradual decreases in the pH of control and 1.5 KGy irradiated meat balls as well as all samples of mashed potatoes. Irradiation treatments had no effects on the sensory properties (appearance, odor and taste) of all meal samples and extended their time of sensory preference. Finally, 3 KGy dose of gamma irradiation appeared to be an optimum dose for improving the quality of ready-to-eat cooked meat balls and mashed potatoes.