Effect of trans-Cinnamaldehyde on Inhibition and Inactivation of Cronobacter sakazakii Biofilm on Abiotic Surfaces

The efficacy of trans-cinnamaldehyde (TC), an ingredient in cinnamon oil, for inhibiting biofilm synthesis (560 and 750 mu M TC) and inactivating mature biofilms (23 and 38 mM TC) of Cronobacter sakazakii was investigated at 24 and 12 degrees C in the presence and absence of reconstituted infant formula on polystyrene plates, stainless steel coupons, feeding bottle coupons, and enteral feeding tube coupons. Additionally, TC's effect on the expression of genes critical for biofilm formation in C. sakazakii was determined by reverse transcription quantitative PCR. TC inhibited and inactivated C. sakazakii biofilms on all matrices tested at both temperatures. C. sakazakii was reduced by >4.0 and 3.0 log CFU/ml after 96 h of exposure to 38 mM and 750 mu M TC, respectively. Reverse transcription quantitative PCR results revealed that TC significantly (P <= 0.05) down-regulated biofilm-associated genes in C. sakazakii. TC could potentially be used to control C. sakazakii biofilms on infant formula feeding equipment and preparatory areas.