ARS | Publication request: Concentration-dependent inhibition of Escherichia coli O157:H7 and potentially carcinogenic heterocyclic amines in heated ground beef patties by apple,olive,and onion powders and clove bud oil

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 7, 2012
Publication Date: March 7, 2012
Citation: Rounds, L., Havens, C.M., Feinstein, Y., Friedman, M., Ravishankar, S. 2012. Concentration-dependent inhibition of Escherichia coli O157:H7 and potentially carcinogenic heterocyclic amines in heated ground beef patties by apple,olive,and onion powders and clove bud oil. Journal of Agricultural and Food Chemistry. 60:3792-3799. doi: 10.1021/jf204062p.

Interpretive Summary: The objective of this collaborative study with the University of Arizona, supported by the American Cancer Society through the Arizona Cancer Center, is to improve microbial food safety and human health. In the present study, we have shown that increased concentrations of a commercial olive extract prepared from organic olive juice and a commercial onion powder were highly effective in reducing both E. coli O157:H7 and the formation of two potentially carcinogenic heterocyclic amines, MeIQx and PhIP, in grilled beef patties (hamburgers). These formulations were more effective than an apple polyphenol extract or clove bud essential oil. These natural and safe plant-derived formulations can potentially be used for their dual beneficial antimicrobial and anti-heterocyclic amine effects in grilled meats.

Technical Abstract: We determined the effects of plant compounds on Escherichia coli O157:H7 and two major carcinogenic heterocyclic amines (HCAs), 2-amino-3,8-dimethylamidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5b]pyridine (PhIP) in grilled ground beef patties. Ground beef with added apple and olive extracts, onion powder, and clove bud oil at three concentrations was inoculated with E. coli (107 CFU/g. The beef was made into patties and then cooked to reach 45 °C at the geometric center, flipped and cooked for a further 5 min. Cooled samples were taken for microbiological and HCA analyses using mass spectrometry. Olive extract at 1% had no effect, whereas at 3% and 5% it reduced E. coli below detection limits. Reductions of 0.7, 1.0 and 1.9 logs were observed with 1, 3 and 5% apple extract, respectively. Clove bud oil was less effective at 0.1 and 0.3%. At 3 and 5%, olive or apple extracts reduced MeIQx by 49.1 and 50.9 % and PhIP by 50.6 and 65.2%, respectively. Onion powder at 3% reduced PhIP by 80.7%. Clove bud oil at 0.3 and 0.5% induced the formation of MeIQx by 19.7 and 61.5%, respectively. The results show that inactivation of E. coli O157:H7 and suppression of HCA formation in grilled meats was achieved through addition of optimized amounts of selected compounds.