title: Effects of Plant-Derived Extracts, Other Antimicrobials, and Their Combinations against Escherichia coli O157:H7 in Beef Systems.
abstract: The antimicrobial effects of thyme oil (TO), grapefruit seed extract (GSE), and basil essential oil, alone or in combination with cetylpyridinium chloride (CPC), sodium diacetate, or lactic acid, were evaluated against Escherichia coli O157:H7 in a moisture-enhanced beef model system. The model system was composed of a nonsterile beef homogenate to which NaCl (0.5%) and sodium tripolyphosphate (0.25%) were added, together with the tested antimicrobial ingredients. Beef homogenate treatments were inoculated (ca. 3 log CFU/ml) with rifampin-resistant E. coli O157:H7 (eight-strain mixture) and incubated at 15 °C (48 h). The most effective individual treatments were TO (0.25 or 0.5%) and GSE (0.5 or 1.0%), which immediately reduced (P < 0.05) pathogen levels by ≥ 3.4 log CFU/ml. Additionally, CPC (0.04%) reduced initial E. coli O157:H7 counts by 2.7 log CFU/ml. Most combinations of the tested plant-derived extracts with CPC (0.02 or 0.04%) and sodium diacetate (0.25%) had an additive effect with respect to antibacterial activity. In a second study, antimicrobial interventions were evaluated for their efficacy in reducing surface contamination of E. coli O157:H7 on beef cuts and to determine the effect of these surface treatments on subsequent internalization of the pathogen during blade tenderization. Beef cuts (10 by 8 by 3.5 cm) were inoculated (ca. 4 log CFU/g) on one side with the rifampin-resistant E. coli O157:H7 strain mixture and were then spray treated (20 lb/in(2), 10 s) with water, GSE (5 and 10%), lactic acid (5%), or CPC (5%). Untreated (control) and spray-treated surfaces were then subjected to double-pass blade tenderization. Surface contamination (4.4 log CFU/g) of E. coli O157:H7 was reduced (P < 0.05) to 3.4 (5% CPC) to 4.1 (water or 5% GSE) log CFU/g following spray treatment. The highest and lowest transfer rates of pathogen cells from the surface to deeper tissues of blade-tenderized sections were obtained in the untreated control and CPC-treated samples, respectively.
authors.affiliation: Center for Meat Safety & Quality, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA; Division of Food Additives and Packaging, Department of Food Safety Evaluation, Ministry of Food Drug Safety, Chungju-si, Chungbuk 363-700, Korea.
authors.forename: Kyung Yuk
authors.initials: KY
authors.lastname: Ko
authors.affiliation: Center for Meat Safety & Quality, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA.
authors.forename: Ifigenia
authors.initials: I
authors.lastname: Geornaras
authors.affiliation: Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 143-701, Korea.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Paik
authors.affiliation: Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 143-701, Korea.
authors.forename: Kee-Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Center for Meat Safety & Quality, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA. john.sofos@colostate.edu.
authors.forename: John N
authors.initials: JN
authors.lastname: Sofos
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002417:Cattle; D002594:Cetylpyridinium / Q000494:pharmacology; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000187:drug effects*; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D056604:Grape Seed Extract / Q000494:pharmacology; D019344:Lactic Acid / Q000494:pharmacology; D031339:Ocimum; D009822:Oils, Volatile / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology; D000069466:Red Meat / Q000382:microbiology*; D046930:Thymus Plant
chemical_list: D000890:Anti-Infective Agents; D056604:Grape Seed Extract; D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils; D019344:Lactic Acid; D002594:Cetylpyridinium; C051168:basil oil