Antibacterial and antibiofilm properties of cinnamon essential oil on Pseudomonas tolaasii and application of potato starch/CEO active pads in preservation of mushroom (Agaricus bisporus)

Abstract

Pseudomonas tolaasii (P. tolaasii) is considered to be the main pathogen of brown spot disease in mushrooms. Cinnamon essential oil (CEO), a natural bacteriostatic agent, has potential application prospects in the field of food preservation. The purpose of this study was to explore the antibacterial mechanism of CEO on P. tolaasii, and to prepare an active pad to study the preservation effect of mushroom, so as to provide a basis for the development of natural antibacterial agents. P. tolaasii was isolated from browning mushroom and identified by 16S rRNA gene sequencing. The antibacterial and antibiofilm activities of cinnamon essential oil (CEO) on P. tolaasii and its application in mushrooms were investigated. The results indicated that CEO had a significant inhibitory effect on P. tolaasii. After the CEO treatment, the surface of P. tolaasii cells was damaged, and significant leakage of entocyte was observed. In addition, CEO could effectively induce oxidative stress and lipid peroxidation in P. tolaasii cells, and cause irreversible damage to cell membranes, leading to energy and respiratory metabolism disorders. The activity of ROS defense enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were significantly inhibited (P < 0.05), aggravating the oxidative damage to P. tolaasii. The crystal violet staining assay and scanning electron microscopy revealed that CEO treatment not only inhibited biofilm formation, but also effectively eradicated mature biofilm. The application effects displayed that the active pads packing containing CEO had excellent antibacterial effect and maintain the quality of mushroom (Agaricus bisporus). The results of this study will provide references for further research and application of natural food antibacterial agents.