title: Characterization of an extremely heat-resistant Escherichia coli obtained from a beef processing facility.
abstract: OBJECTIVE
  This study aimed to determine the survival of Escherichia coli strains during steam and lactic acid decontamination interventions currently used by the beef-processing industry, and to determine their heat resistance.
  
  
  RESULTS
  Strains were grouped into cocktails of five strains each differing in their RAPD patterns for subsequent identification. Steam and lactic acid treatments on meat reduced cell counts of E. coli strain cocktails by 90-99%. The 20 slaughter plant isolates exhibited only minor variation in their resistance to steam and lactic acid treatments but were more resistant than reference strains (three strains) or isolates from live cattle (seven strains). D(60) values of strains from live cattle, and reference strains ranged from 0·1 to 0·5 min, in keeping with literature data. However, D(60) values of current slaughter plant isolates ranged between 15 for E. coli DM18.3 and 71 min AW 1.7. Cell counts of E. coli AW 1.7 were reduced by <5 log(10) CFU g(-1) in ground beef patties cooked to an internal temperature of 71°C.
  
  
  CONCLUSIONS
  Strains of E. coli that survive cooking of ground beef to the recommended internal temperature of 71°C can be isolated from beef-processing facilities.
  
  
  CONCLUSIONS
  Pathogen interventions in current commercial beef slaughter may select for extremely heat-resistant strains of E. coli.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors.forename: E A
authors.initials: EA
authors.lastname: Dlusskaya
authors.forename: L M
authors.initials: LM
authors.lastname: McMullen
authors.forename: M G
authors.initials: MG
authors.lastname: Gänzle
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D002417:Cattle; D015169:Colony Count, Microbial; D003296:Cooking; D003666:Decontamination / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification / Q000502:physiology*; D005525:Food-Processing Industry / Q000379:methods; D006358:Hot Temperature; D019344:Lactic Acid / Q000494:pharmacology; D008460:Meat / Q000382:microbiology; D050296:Microbial Viability / Q000187:drug effects; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000890:Anti-Infective Agents; D019344:Lactic Acid