Optimization of nisin concentration in fermented beef sausage to decrease sodium nitrite concentration in the final product

Bacteriocins such as nisin produced by lactic acid bacteria exhibit antimicrobial activity at very low concentrations without side effects. The aim of the present study was to optimize nisin content in fermented beef to achieve optimum pH and microbial community as well as reduction of nitrite concentration in the final product. In this experimental laboratory research, fermented beef was prepared using Lactobacillus plantarum and Lactobacillus sakei. Then, optimization of nisin and sodium nitrite concentrations were done by response surface methodology based on the pH decrease and spoilage causing microbial count in fermented product. Among treatments, 3 treatments with respectively 80 and 100 ppm sodium nistrit and nisin, 128.28 and 140 ppm sodium nitrite and nisin and 180 and 196 ppm sodium nistrit and nisin showed the best results based on pH and spoilage causing microbial count reduction. The residual nitrite contents in these three treatments reduced to 5.7 to 8.47 ppm, which were lower than the limited amount. Clostridium was absent in all three beef products after one mount storage at 4 °C. Addition of nisin to fermented beef significantly decreased the nitrite concentration. Therefore, the usage of nisin is recommended as a preservative in beef sausage industries in Iran.