Inactivation of Escherichia coli O157:H7 by essential oil from Cinnamomum zeylanicum

ABSTRACT

Escherichia coli O157H7 is a pathogen strain, which causes hemorrhagic colitis, hemolytic uremic syndrome and thrombotic thrombocytopenic purpura in humans. The control of bacterial cells in foods is an important factor to reduce foodborne diseases due to E. coli O157H7. Assays to inactivate E. coli O157H7 were carried out by using the cinnamon oil obtained by steam distillation for 6 hours. When E. coli O157H7 cells were incubated at 37°C for 2 hours in the presence of 0.025 percent of the essential oil from cinnamon, a dramatic decrease was observed in the viable counts (from 10(7) to 3.10(4) CFU/mL-1). In the presence of 0.05 percent of the oil, most of cells were killed after 30 min, suggesting that the antimicrobial activity of essential oil is bactericidal against E. coli. The minimal inhibitory concentration of the essential oil from cinnamon was around 625 ppm against E. coli O157H7 and E. coli ATCC 25921, around 1250 ppm against E. coli ATCC25922 and around 2500 ppm against E. coli ATCC11105.