Effects of Gamma Radiation on Microbiological Status, Fatty Acid Composition, and Color of Vacuum-Packaged Cold-Stored Fresh Pork Meat
2009
Pork meat samples were inoculated with high or low levels (106 or 103 CFU/g) of Salmonella Enteritidis, vacuum packaged, exposed to γ radiation (1.0, 2.5, and 4.7 kGy), and stored for 1 month at 4 ± 1°C. In highly contaminated samples, the target strain was completely eliminated only by the 4.7 kGy radiation dose, whereas in samples at the lower contamination level, 2.5 kGy was sufficient to eliminate Salmonella Enteritidis. The highest of the applied radiation doses reduced the aerobic microflora and extended the sample's refrigeration shelf life by at least 2 weeks. The fatty acid profile of pork meat was not significantly affected by any of the applied radiation doses. Irradiation increased the proportion of saturated fatty acids (SFA) and decreased the content of the polyunsaturated fatty acids (P < 0.05). Irradiation also affected negatively the proportions of the nutritional indexes ω-6/ω-3, SFA/monounsaturated fatty acids, and SFA/polyunsaturated fatty acids. The proportion of the trans fatty acids C18:1ω-9 t9 and C18:2 t9,t12 in the total fatty acids was nearly doubled (90 and 86%, respectively) in the samples that had been exposed to 4.7 kGy. None of the applied radiation doses changed the lightness (L* value) of the meat, but redness (a*) and yellowness (b*) increased, particularly for the samples treated with 4.7 kGy.
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