title: Antimicrobial effect of herb extracts against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella typhimurium associated with beef.
abstract: The effects of plant extracts against pathogenic bacteria in vitro are well known, yet few studies have addressed the effects of these compounds against pathogens associated with muscle foods. A series of experiments was conducted to determine the effectiveness of a commercially available, generally recognized as safe, herb extract dispersed in sodium citrate (Protecta One) or sodium chloride (Protecta Two) against Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes associated with beef. In the first experiment, E. coli O157:H7, Salmonella typhimurium, and L. monocytogenes inoculated onto beef and subjected to surface spray treatments with 2.5% solutions of Protecta One or Protecta Two were not affected by immediate application (day 0) of the herbal extracts. However, after 7 days of storage at 4 degrees C, E. coli O157:H7 was reduced by >1.3 log10 CFU/cm2 by Protecta Two; L. monocytogenes was reduced by 1.8 and 1.9 log10 CFU/cm2 by Protecta One and Protecta Two, respectively; Salmonella typhimurium was not reduced >0.3 log10 CFU/cm2 by either extract by day 7. In the second experiment, 2.5% Protecta Two (wt/vol or wt/wt) added to inoculated lean and adipose beef trim, processed, and packaged as ground beef chubs (80% lean, 20% adipose), did not reduce pathogen populations >0.5 log10 CFU/g up to 14 days at 4 degrees C. In the third experiment, surface spray treatments of beef with 2.5% lactic acid or 2.5% solutions of Protecta One or Protecta Two, vacuum packaged, and stored up to 35 days at 4 degrees C did reduce E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium slightly. These studies suggest that the use of herb extracts may afford some reductions of pathogens on beef surfaces; however, the antimicrobial activity may be diminished in ground beef by adipose components.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA. cnc3@psu.edu
authors.forename: C N
authors.initials: CN
authors.lastname: Cutter
mesh_terms: D000818:Animals; D002417:Cattle; D019453:Escherichia coli O157 / Q000187:drug effects*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D008089:Listeria monocytogenes / Q000187:drug effects*; D019684:Magnoliopsida; D008461:Meat Products / Q000382:microbiology*; D010936:Plant Extracts / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects*; D013499:Surface Properties
chemical_list: D010936:Plant Extracts