Abstract: The antibacterial activity and mechanism of rhamnolipids (RLs) against Bacillus cereus spores were analyzed from the aspects of appearance, morphology, and cell membrane state. The results showed that minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of RLs were 80.0 and 160.0 mg/L, respectively. Both concentrations of RLs caused severe shrinkage and depression on the surface of spores, and disrupted the integrity and permeability of the spore cell membrane, leading to the leakage of intracellular electrolytes, DNA and proteins. In addition, RLs inhibited and inactivated B. cereus spores by various mechanisms such as decreasing heat resistance, generating oxidative stress, reducing surface adhesion, and binding to and interfering with DNA molecules. The results of this study will contribute to the development and application of RLs in the field of food safety.

Key words: rhamnolipids; Bacillus cereus; spores; antibacterial mechanism