Effects of low-level gamma irradiation on the characteristics of fermented pork sausage during storage

Abstract

The effect of gamma irradiation (0.5, 1, 2, and 4kGy) on the quality of vacuum-packaged dry fermented sausages during refrigerated storage was evaluated. At Day 0 of irradiation, the pH, redness (CIE a⁎), yellowness (CIE b⁎), 2-thiobarbituric acid-reactive substances (TBARS) and volatile basic nitrogen (VBN) values of samples irradiated at 2 and 4kGy were higher (p<0.05), but the CIE L⁎ values (lightness) were lower than those of the non-irradiated control (p<0.05). At<1kGy irradiation, however, the pH, CIE L⁎, CIE a⁎ and CIE b⁎-value of samples were not significantly influenced by irradiation. The CIE a⁎, and CIE b⁎-values of samples irradiated at 2 and 4kGy decreased with the increase of storage time. The VBN, TBARS, and CIE L⁎-values of samples irradiated at 4kGy were not changed significantly during refrigerated storage for 90 days (p>0.05). The total plate counts (TPC) and lactic acid bacteria (LAB) in the samples irradiated at 4kGy were significantly lower (p<0.01) than those with lower irradiation doses. At the end of storage, the TPC, coliform, and LAB in the samples were not increased after irradiation at 1, 0.5 and 1kGy, respectively. TPC and LAB were not detected in samples irradiated at 4kGy at Day 90. In addition, no coliform bacteria were found in samples irradiated at 1kGy during refrigerated storage. Sensory evaluation indicated that the rancid flavor of samples irradiated at 4kGy was significantly higher, but aroma and taste scores were lower than those of the control at Day 3 of storage. Irradiation of dry fermented sausages at 2kGy was the best conditions to prolong the shelf-life and decrease the rancid flavor without significant quality deterioration.