Combined Effect of Aging and Irradiation on Physicochemical Quality of Pork Shoulder

The effect of combined electron-beam irradiation and aging temperature of pork on microbiological and physicochemical properties was investigated. The samples from pork shoulder were irradiated with 0 or 2 kGy, vacuum-packaged, and assigned randomly to an aging temperature ($2^{\circ}C$, $10^{\circ}C$, or $25^{\circ}C$) during 8 d. On 4 d of aging at $25^{\circ}C$, total aerobic bacteria of non-irradiated ones reached 7 Log CFU/g which is no salable levels. Shear force values of irradiated meat after aging for 2 and 4 d at $25^{\circ}C$ was lower than those aged at $2^{\circ}C$. Irradiated samples at $2^{\circ}C$ had lower cooking loss after 2 and 8 d of aging, compared with other aging temperatures. Irradiation did not accelerate 2-thiobarbituric acid reactive substance (TBARS) value when aged up to 4 d. Irradiated samples aged at $10^{\circ}C$ and $25^{\circ}C$ for 8 d scored significantly higher TBARS values. With an increased aging period, $a^*$ and $b^*$ in irradiated samples at $2^{\circ}C$ slightly increased, but irradiation caused negligible changes in meat color. The highest contents of a desirable nucleotide flavor compounds (inosine-5-phosphate) were observed in pork at $2^{\circ}C$ when aged for 4 and 8 d, while the lowest contents were observed at $25^{\circ}C$. Aging in irradiated pork for 8 d at $2^{\circ}C$ resulted in optimal condition with improved meat quality and minimal microbiologically negative defect.