The inhibition mechanism of ϵ‐polylysine against Bacillus cereus emerging in surimi gel during refrigerated storage

Abstract

BACKGROUND Refrigeration is commonly used in the processing and storage of surimi products. However, refrigerated surimi products are susceptible to microbial contamination, which leads to deterioration of the products and shortens their shelf life. The aims of the present study were therefore 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 spoilage bacterium. RESULTS ϵ‐Polylysine with a high degree of polymerization (20–30K) proved able to decrease the total number of colonies 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. CONCLUSION 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. © 2018 Society of Chemical Industry

Self-Reporting and Photothermally Enhanced Rapid Bacterial Killing on a Laser-Induced Graphene Mask

“…coli cells on hydrophilic LIG (red circle in Figure b) are voided with disruption of the outer membrane, whereas that on hydrophobic LIG are shriveled and flattened (red circle in Figure d). Both are the typical morphology of bacteria losing viability. − The E. coli viability on two kinds of LIG was statistically summarized in Figure e.…”

Epsilon-poly-L-lysine: Recent Advances in Biomanufacturing and Applications

“…Multiple reports have described that ε-PL inhibits the growth of various microorganisms by affecting the integrity and permeability of their cell walls and cell membranes ( Hyldgaard et al, 2014 ; Wei M. et al, 2018 ; Lan et al, 2019 ; Su et al, 2019 ; Liu H. et al, 2020 ; Dou et al, 2021 ). For example, in Escherichia coli O157:H7 ( Figure 6A ), the interactions between ε-PL and phospholipid groups result in distorting and shriveling of the cell membrane in a non-specific, carpet-like mechanism, in which the membrane is forced to fold in on itself, contributing to vesicle/micelle and toroidal pore formation ( Hyldgaard et al, 2014 ).…”

Efficacy of epsilon-poly-L-lysine inhibition of postharvest blue mold in apples and potential mechanisms

“…Intracellular ROS and plasma membrane integrity of P. expansum spores were examined as previously described (Su et al, 2018;Li et al, 2017a;Shi et al, 2012). Briefly, conidia of P. expansum were cultured in PDB media amended with various concentration of ε-PL (0, 200, and 400 mg L −1 ) for 9 h at a constant temperature of 25 °C on a rotary shaker set at 150 rpm.…”