Effect of Nisin on the Quality Change of Roasted Shrimp with High Water Content during Storage

To investigate the effect of Nisin on the storage of roasted shrimp with high water content at room temperature, different concentrations of Nisin (20, 60 and 100 mg/kg) were added to the rosted shrimp samples. Sensory evaluation combined with the total viable count (TVC), the Bacillus cereus count, the total volatile basic nitrogen (TVB-N) and the pH value were used as indicators, to evaluate the quality of rosted shrimp samples. The results showed that the sensory evaluation scores decreased during storage of samples, and the TVC, the Bacillus cereus count, the TVB-N and the pH value of the samples increased gradually. With the increase of added Nisin, the growth of the TVC, the Bacillus cereus count and the TVB-N slowed down. On the 6th day, the TVC of the control group reached the threshold specified in the Chinese industry standard "Seasoned roasted shrimp" (3×10⁴ CFU/g), while the shelf life of samples with 20, 60 and 100 mg/kg Nisin were extended to 8, 12 and 14 days, respectively. This study showed that Nisin had an inhibitory effect on the growth of microorganisms such as Bacillus cereus in the roasted shrimp with high water content, and it could effectively prolong the shelf life of the product.