Purpose: The aim of this work was to evaluate the antimicrobial effect of nisin incorporated in cellulose casing on the population of lactic acid bacteria and total aerobic count in bologna sausage storage in vacuum packaging at 25°C.
Methods: Bologna sausages were produced in a pilot plant. The mixture of ingredients was stuffed into pretreated cellulose casings and the products were heat processed. After cooling the sausages were vacuum packaged and stored at 25.0°C. Cellulose casings were treated with nisin (1.0 g·l-1 Nisaplin®), at 40°C for 40 minutes, prepared in the following solutions: 1) potassium phosphate buffer (pH 6.0); 2) 0.1 % phosphoric acid (pH 2.0). As control, cellulose casings were also treated in the same solutions but without nisin. The population of lactic acid bacteria (LAB) and total aerobic count in bologna sausages were determinate during storage. The experiments were repeated three times and results analyzed using ANOVA.
Results: The treatment of cellulose casing with nisin solution (pH 6.0) reduced significantly (P < 0.05) the population of LAB and total aerobic count in bologna sausage by 1.7 log and 1.9 log at day 30 of storage and by 3.5 log and 3.7 log at the 50th day, respectively. However no inhibitory effect (P > 0.05) was observed when cellulose casings were treated with nisin solution in phosphoric acid (pH 2.0).
Significance: The results demonstrate that nisin (1.0 g·l-1) in potassium phosphate buffer solution (pH 6.0) can be incorporated in cellulose casing to reduce total aerobic count and lactic acid bacteria in vacuum packaged bologna sausage.