Plant extracts, spices, and essential oils inactivate Escherichia coli O157:H7 and reduce formation of potentially carcinogenic heterocyclic amines in cooked beef patties

J Agric Food Chem. 2012 Apr 11;60(14):3792-9. doi: 10.1021/jf204062p. Epub 2012 Mar 27.


Meats need to be heated to inactivate foodborne pathogens such as Escherichia coli O157:H7. High-temperature treatment used to prepare well-done meats increases the formation of carcinogenic heterocyclic amines (HCAs). We evaluated the ability of plant extracts, spices, and essential oils to simultaneously inactivate E. coli O157:H7 and suppress HCA formation in heated hamburger patties. Ground beef with added antimicrobials was inoculated with E. coli O157:H7 (10(7) CFU/g). Patties were cooked to reach 45 °C at the geometric center, flipped, and cooked for 5 min. Samples were then taken for microbiological and mass spectrometry analysis of HCAs. Some compounds were inhibitory only against E. coli or HCA formation, while some others inhibited both. Addition of 5% olive or apple skin extracts reduced E. coli O157:H7 populations to below the detection limit and by 1.6 log CFU/g, respectively. Similarly, 1% lemongrass oil reduced E. coli O157:H7 to below detection limits, while clove bud oil reduced the pathogen by 1.6 log CFU/g. The major heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were concurrently reduced with the addition of olive extract by 79.5% and 84.3% and with apple extract by 76.1% and 82.1%, respectively. Similar results were observed with clove bud oil: MeIQx and PhIP were reduced by 35% and 52.1%, respectively. Addition of onion powder decreased formation of PhIP by 94.3%. These results suggest that edible natural plant compounds have the potential to prevent foodborne infections as well as carcinogenesis in humans consuming heat-processed meat products.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Anticarcinogenic Agents / pharmacology
  • Carcinogens / analysis*
  • Carcinogens / chemistry
  • Cattle
  • Clove Oil / pharmacology
  • Escherichia coli O157 / drug effects*
  • Fruit / chemistry
  • Hot Temperature
  • Imidazoles / analysis
  • Malus / chemistry
  • Meat / analysis
  • Meat / microbiology*
  • Oils, Volatile / pharmacology*
  • Olea / chemistry
  • Onions / chemistry
  • Plant Extracts / pharmacology*
  • Quinoxalines / analysis
  • Spices*


  • Anti-Bacterial Agents
  • Anticarcinogenic Agents
  • Carcinogens
  • Clove Oil
  • Imidazoles
  • Oils, Volatile
  • Plant Extracts
  • Quinoxalines
  • 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline
  • 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine