The inhibition mechanism of ε-Polylysine against Bacillus cereus emerging in surimi gel during refrigerated storage.

BACKGROUND

Refrigeration is a common method in the process and storage of surimi products. However, refrigerated surimi products are susceptible to microbial contamination, that lead to deterioration of products and shorten the shelf life. Therefore, the aims of the present study were to evaluate the effects of ε-polylysine (ε-PL) on spoilage bacteria in surimi products, and to investigate the antibacterial mechanism of Bacillus cereus, which is the dominant bacterium in spoilage bacteria.

RESULTS

A high degree of polymerization (20~30K) ε-PL proved able to decrease the total colonies number in surimi products and showed an obvious antibacterial effect against B. cereus. After ε-PL treatments, the distinct broken areas on the bacterial surfaces and the aggregations of cells were observed by scanning electron microscope (SEM). The intracellular materials such as small molecules, soluble proteins and deoxyribonucleic acids in the cells were analyzed, which revealed the destructive effects of ε-PL on bacterial cells. Experiments with propidium iodide (PI) infiltration experiments verified that the permeability of cell membranes was enhanced by ε-PL treatment.

CONCLUSIONS

These results indicated that ε-PL could destroy the cell membranes and change the permeability of B. cereus, and subsequently the cell contents leaked out to achieve antibacterial effects. This article is protected by copyright. All rights reserved.