title: Plant extracts, spices, and essential oils inactivate Escherichia coli O157:H7 and reduce formation of potentially carcinogenic heterocyclic amines in cooked beef patties.
abstract: 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.
authors.affiliation: Department of Veterinary Science and Microbiology, University of Arizona, Tucson, Arizona 85721, United States.
authors.forename: Liliana
authors.initials: L
authors.lastname: Rounds
authors.forename: Cody M
authors.initials: CM
authors.lastname: Havens
authors.forename: Yelena
authors.initials: Y
authors.lastname: Feinstein
authors.forename: Mendel
authors.initials: M
authors.lastname: Friedman
authors.forename: Sadhana
authors.initials: S
authors.lastname: Ravishankar
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D002273:Carcinogens / Q000032:analysis* / Q000737:chemistry; D002417:Cattle; D045783:Clove Oil / Q000494:pharmacology; D019453:Escherichia coli O157 / Q000187:drug effects*; D005638:Fruit / Q000737:chemistry; D006358:Hot Temperature; D007093:Imidazoles / Q000032:analysis; D027845:Malus / Q000737:chemistry; D008460:Meat / Q000032:analysis / Q000382:microbiology*; D009822:Oils, Volatile / Q000494:pharmacology*; D031658:Olea / Q000737:chemistry; D019697:Onions / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology*; D011810:Quinoxalines / Q000032:analysis; D017365:Spices
chemical_list: D000900:Anti-Bacterial Agents; D016588:Anticarcinogenic Agents; D002273:Carcinogens; D045783:Clove Oil; D007093:Imidazoles; D009822:Oils, Volatile; D010936:Plant Extracts; D011810:Quinoxalines; C036990:2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine