Title: The mechanism of bactericidal action of cinnamaldehyde and Sporan on Escherichia coli and Salmonella Authors
Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2012
Publication Date: April 19, 2012
Citation: Yossa, N., Patel, J.R., Macarisin, D., Millner, P.D., Murphy, C.A., Bauchan, G.R., Lo, M. 2012. The mechanism of bactericidal action of cinnamaldehyde and Sporan on Escherichia coli and Salmonella. BARC Poster Day. #57. Technical Abstract: Foodborne illnesses associated with the consumption of fresh produce have increased in recent years. Escherichia coli O157:H7 and Salmonella have been implicated as pathogens involved in the illnesses. Previous research has indicated limited efficacy of chlorine as a produce wash in removing pathogens from fresh produce. Further, chlorine may also form harmful chlorinated compounds such as chloramines and trihalomethanes in water. Due to these limitations, there is a need for alternative sanitizers in reducing or eliminating pathogens from produce. We evaluated the effect of natural antimicrobials: cinnamaldehyde and Sporan on E. coli O157: H7 and Salmonella. A five strain cocktail of E. coli O157:H7 and Salmonella were inoculated in Luria-Bertoni broth (6 log CFU/ml) containing cinnamaldehyde or Sporan (800 and 1000 ppm) alone or in combination with 200 ppm acetic acid, and incubated at 37°C for up to 6 h. E. coli O157:H7 were undetectable after 1 h in presence of cinnamaldehyde whereas 0.23 log and 0.43 log CFU/ml Salmonella populations were recovered from LB broth containing 800 and 1000 ppm cinnamaldehyde, respectively. A 1000 ppm Sporan significantly reduced E. coli O157:H7 and Salmonella populations by 5.41 and 3.28 log cfu/ml, respectively after 4 h. The synergistic effect of acetic acid was not evident as it did not enhance the bactericidal activity of oils. Scanning and Transmission electron microscopy of oil-treated bacterial cells revealed cell structural damage and leakage of cellular content in E. coli O157:H7 and Salmonella, repsectively.