Improved Storage Stability of Sausage Based on the Dual Effects of Sodium Nitrite on Color Development and Bacterial Inhibition

In this study, ground yak meat was treated with 0, 30, 60, 100, and 150 mg/kg NaNO₂ and stored at 4°C for 96 h. Color, myoglobin redox forms, nitrosylmyoglobin (NOMb), thiobarbituric acid reactive substances (TBARS), protein carbonyls, residual nitrite, pH, and bacterial counts were measured. The results indicated that 30 mg/kg NaNO₂ was sufficient for color development, whereas 100 mg/kg NaNO₂ was required to reduce TBARS, protein carbonyls, and bacterial counts during storage. Subsequently, a fixed total of 100 mg/kg NaNO₂ was selected to investigate its effect on emulsion-type yak sausages by distributing it between the meat batter and the casing at the following ratios: 100/0 (control), 75/25 (PG-1), 50/50 (PG-2), 25/75 (PG-3), and 0/100 (PG-4). The sausages were then stored at 20°C for 8 d. Increasing the amount of NaNO₂ on the casing produced a dose-dependent reduction in bacterial counts, with PG-3 and PG-4 maintaining TVC < 6.0 log CFU/g on day 6. However, PG-4 had a lower a* (9.71) on day 8, and its day 0 residual nitrite was 40.2 mg/kg, exceeding the 30 mg/kg limit. PG-3 maintained a* = 11.19 and TVC = 6.59 log CFU/g on day 8, with residual nitrite ≤ 30 mg/kg. These results indicate that it is an effective way to improve the overall application effect of NaNO₂ in sausages based on the color of the meat batter and the antibacterial effect of sausage casing. PRACTICAL APPLICATIONS: This study provides a practical strategy for reducing the total amount of NaNO₂ used in sausages without compromising product quality. Distributing NaNO₂ between the meat batter and the casing effectively maintained color, enhanced microbial safety, and preserved the antioxidant capacity of sausages.