Characterization of emetic Bacillus cereus biofilm formation and cereulide production in biofilm

[Display omitted] •Dynamic processes of biofilm formation and cereulide production under four different conditions.•The substrate has an impact on the formation of biofilms and cereulide of Bacillus cereus.•The cereulide levels in biofilms formed in BHI medium are mostly higher than those formed in UHT milk. Bacillus cereus is a well-known foodborne pathogen that can cause human diseases, including vomiting caused by emetic toxin, cereulide, requiring 105-108 cells per gram to cause the disease. The bacterial cells may be eliminated during processing, but cereulide can survive in most processing techniques due to its resistance to high temperatures, extreme pH and proteolytic enzymes. Herein, we reported dynamic processes of biofilm formation of four different types and cereulide production within the biofilm. Confocal laser scanning microscopy (CLSM) images revealed that biofilms of the four different types reach each stage at different time points. Among the extracellular polymeric substances (EPS) components of the four biofilms formed by the emetic B. cereus F4810/72 strain, proteins account for the majority. In addition, there are significant differences (p