Influence of physiological cell stages on biofilm formation by Bacillus cereus of dairy origin

The effect of initial physiological stages, i.e., sessile, vegetative, and spore (SP), of Bacillus cereus on its biofilm formation potential was investigated. Enhanced biofilm formation was observed in diluted tryptic soy broth in comparison with milk menstruum. Growth rate constants of the biofilm growth curve (BGC) indicated that SP was the most efficient cell stage to initiate and form a biofilm. Comparative evaluation of the BGC and suspension growth curve revealed that former's lag phase corresponded to latter's log phase (4-16 h). Through being surface adhered and in lag phase, these cells might be more resistant to cleaning. Moreover, the greater SP percentage in spore initiated biofilm than spore initiated suspension presents an obvious food safety threat. These findings suggest a noteworthy effect of initial cell stages on biofilm formation potential of B. cereus and may be helpful in designing/scheduling more efficient interventions to minimize associated health hazards. (C) 2011 Elsevier Ltd. All rights reserved.