Bacteriocidal effects and inhibition of cell separation of cinnamic aldehyde on Bacillus cereus

AIMS: In this study, bacteriocidal effects of cinnamic aldehyde on Bacillus cereus were investigated. METHODS: The bacterial culture or cell suspension in 0.85% NaCl was treated with cinnamic aldehyde at a concentration of 0.3 ml l(-1). Viable cells were counted on a nutrient agar plate. Protein leakage from the cell was determined using a protein dye. Cell morphology was observed using a scanning electron microscope. RESULTS: Bacillus cereus cells were the most sensitive to cinnamic aldehyde among four different food-borne pathogens. When the cells were treated with 0.3 ml l(-1) of cinnamic aldehyde, the viable counts decreased about 6 log cycles after 6 h of incubation. The bacterial cells remained unlysed although they were killed by cinnamic aldehyde. Treatment of cinnamic aldehyde to the exponential phase cells resulted in no significant protein leakage but strong inhibition of cell separation. CONCLUSIONS: The present findings suggest that cinnamic aldehyde exhibits bacteriocidal effects and inhibition of cell separation on B. cereus. SIGNIFICANCE AND IMPACT OF THE STUDY: These data represent an interesting background for a possible mechanism for antibacterial effects of cinnamic aldehyde.